4. Method Statement 20110321

ROAD DEVELOPMENT AUTHORITY MINISTRY OF HIGHWAYS & ROAD DEVELOPMENT THE DEMOCRATIC SOCIALIST REPUBLIC OF SRI LANKA

GREATER COLOMBO URBAN TRANSPORT DEVELOPMENT PROJECT

OUTER CIRCULAR HIGHWAY (OCH) TO THE CITY OF COLOMBO PROJECT – NORTHERN SECTION-1

SCHEDULE VIII Method Statements (Rev.1)

21 March 2011

Prepared by

TAISEI CORPORATION

Greater Colombo Urban Transport Development Project OCH to the City of Colombo Project – Northern Section-1

SCHEDULE VIII Table of Contents

Table of Contents

1. PART 1: CONDITIONS FOR CONSTRUCTION METHODS_____________________________ 1 1.1

1.2

TECHNICAL PREREQUISITES FOR CONSTRUCTION __________________________ 1 1.1.1

Work Programme _____________________________________________________ 1

1.1.2

Temporary access roads ________________________________________________ 2

1.1.3

Additional points to be emphasized _______________________________________ 2

PROJECT DESCRIPTION ___________________________________________________ 5 1.2.1

Introduction __________________________________________________________ 5

1.2.2

Location and objectives _________________________________________________ 5

1.2.3

Major features of Northern Section-1 _____________________________________ 5

1.2.4

Construction schedule __________________________________________________ 7

1.2.4.1 General _____________________________________________________________ 7 1.2.4.2 Preparing and maintaining firm and stable working formation __________________ 7 1.2.4.3 Timely implementation of preliminary works _______________________________ 9 1.2.4.4 Implementation of embankment works in appropriate execution speed __________ 11

1.3

1.2.5

Environmental Management Plan (EMP) _________________________________ 11

1.2.6

Safety and public relations _____________________________________________ 14

PROCESS CONDITIONS ___________________________________________________ 16 1.3.1

Workable days _______________________________________________________ 16

1.3.1.1 Working conditions based on type of work and precipitation __________________ 16 1.3.1.2 Holidays in Sri Lanka ________________________________________________ 16 1.3.1.3 Workable days and operating rate _______________________________________ 16 1.3.2

Material conversion factors ____________________________________________ 18

1.3.3

Production rates______________________________________________________ 18

1.3.3.1 Earthworks _________________________________________________________ 19 1.3.3.2 Paving works _______________________________________________________ 19 1.3.3.3 Bridgeworks ________________________________________________________ 20 1.4

DESCRIPTION OF CRITICAL PATH WORKS _________________________________ 21

1.5

PARTICULAR CONCERNS _________________________________________________ 24 1.5.1

Handover procedure __________________________________________________ 24

1.5.2

Defects liabilities _____________________________________________________ 26

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2. PART 2: CONSTRUCTION METHODS WITH CONSTRUCTION RESOURCES __________ 28 2.1

GENERAL ________________________________________________________________ 28

2.2

OVERALL WORKFLOW ____________________________________________________ 28

2.3

COMMON WORK ITEMS ___________________________________________________ 32 2.3.1

Temporary works ____________________________________________________ 32

2.3.2

Utility relocation works ________________________________________________ 35

2.3.3

Excavation, embankment and hauling works ______________________________ 36

2.3.4

Drainage works ______________________________________________________ 37

2.3.5

Paving works ________________________________________________________ 41

2.4

ENVIRONMENTAL PROTECTION IN THE OCH PROJECT _____________________ 46

2.5

TRAFFIC MANAGEMENT AT NATIONAL ROADS A1, AB10 AND B214 ___________ 50

2.6

SOFT GROUND TREATMENT ______________________________________________ 51

2.7

2.8

2.6.1

General _____________________________________________________________ 51

2.6.2

Proposed disposal locations ____________________________________________ 65

2.6.3

Surcharge ___________________________________________________________ 65

2.6.4

Preloading __________________________________________________________ 66

2.6.5

Monitoring __________________________________________________________ 66

BORROW MATERIALS AND AGGREGATE QUARRIES _________________________ 67 2.7.1

General _____________________________________________________________ 67

2.7.2

Planning and transportation____________________________________________ 67

CONSTRUCTION METHOD OF BRIDGES AND VIADUCTS _____________________ 70 2.8.1

Summary ___________________________________________________________ 70

2.8.2

Workflow ___________________________________________________________ 72

2.8.3

Working hours _______________________________________________________ 73

2.8.4

Piling works _________________________________________________________ 73

2.8.5

Substructure _________________________________________________________ 78

2.8.6

Superstructure _______________________________________________________ 80

2.8.6.1 PC I-girder bridges ___________________________________________________ 80 2.9

CONSTRUCTION METHOD OF KELANI RIVER BRIDGES (STA.16+300) _________ 94

2.10 THERMAL CONTROL FOR STRUCTURAL MASS CONCRETE __________________ 97

3. PART 3: CONTRACTOR’S QUALITY MANAGEMENT PLAN _________________________ 98 3.1

SCOPE AND PURPOSE OF PROJECT QUALITY MANAGEMENT PLAN __________ 98

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3.2

QUALITY OBJECTIVES OF THE PROJECT ___________________________________ 98

3.3

PROJECT QUALITY MANAGEMENT SYSTEM ________________________________ 99

3.4

3.3.1

Engineering/Design Quality Management & Control _______________________ 99

3.3.2

Procurement Quality Management & Control ____________________________ 100

3.3.3

Construction Quality Management & Control ____________________________ 100

INSPECTIONS AND TESTS PLAN __________________________________________ 102

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List of Figures

Fig. 1.2.4.2.1 Example of a plan of working formation around bridge piers __________________ 8 Fig. 1.2.4.2.2 Typical section of working formation ______________________________________ 9 Fig. 1.2.5.1 Example of temporary staging for flood ____________________________________ 13 Fig. 1.2.5.2 Disposal of peat into hollow and covering it by topsoil _________________________ 14 Fig. 1.4.1 Work Programme – Critical Path Activities ___________________________________ 23 Fig. 1.5.1.1 Handover procedure ____________________________________________________ 25 Fig. 1.5.2.1 Remedy work during the defect liability period _______________________________ 27 Fig. 2.2.1 Overall project plan ______________________________________________________ 29 Fig. 2.2.2 Work division into working sections _________________________________________ 30 Fig. 2.2.3 Overall workflow ________________________________________________________ 31 Fig. 2.3.1.1 Example of temporary road outside ROW (box culvert) ________________________ 33 Fig. 2.3.1.2 Example of temporary road outside ROW (overpass bridge) ____________________ 34 Fig. 2.3.4.1 Typical section of pipe culverts and construction sequence _____________________ 38 Fig. 2.3.4.2 Typical section of ditches and construction sequence __________________________ 39 Fig. 2.3.4.3 Typical section of catch basins and construction sequence _____________________ 40 Fig. 2.3.5.1 Pavement structure (subbase course)_______________________________________ 42 Fig. 2.3.5.2 Pavement structure (aggregate road base) __________________________________ 43 Fig. 2.3.5.3 Asphalt pavement structure ______________________________________________ 44 Fig. 2.6.1.1 Soft ground treatment Type-A ____________________________________________ 52 Fig. 2.6.1.2 Soft ground treatment Type-B ____________________________________________ 52 Fig. 2.6.1.3 Sequence of works for soft ground treatment Type-A and Type-B ________________ 53 Fig. 2.6.1.4 Soft ground treatment Type-C ____________________________________________ 54 Fig. 2.6.1.5 Sequence of works for soft ground treatment Type-C __________________________ 56 Fig. 2.6.1.6 Soft ground treatment Type-D ____________________________________________ 56 Fig. 2.6.1.7 Sequence of works for soft ground treatment Type-D and Type-G _______________ 58 Fig. 2.6.1.8 Soft ground treatment Type-E ____________________________________________ 59 Fig. 2.6.1.9 Soft ground treatment Type-F ____________________________________________ 60 Fig. 2.6.1.10 Sequence of works for soft ground treatment Type-E and Type-F _______________ 62 Fig. 2.6.1.11 Soft ground treatment Type-G ___________________________________________ 63 Fig. 2.6.1.12 Soft ground treatment Type-H ___________________________________________ 63 Fig. 2.6.1.13 Sequence of work for soft ground treatment Type-H _________________________ 65 Fig. 2.7.2.1 Locations of supply and disposal plan ______________________________________ 69 Fig. 2.8.2.1 Workflow of bridgeworks ________________________________________________ 72 Fig. 2.8.4.1 Reverse circulation method (RCD) ________________________________________ 76 iv



Fig. 2.8.4.2 All casing method (AC) _________________________________________________ 77 Fig. 2.8.5.1 Steel support system for overhanging column head of viaduct___________________ 79 Fig. 2.8.6.1.1 General arrangement of temporary facility) ________________________________ 81 Fig. 2.8.6.1.2 Precast yard outline ___________________________________________________ 82 Fig. 2.8.6.1.3 Rebar jig detail _______________________________________________________ 83 Fig. 2.8.6.1.4 Rebar cage lifting frame _______________________________________________ 84 Fig. 2.8.6.1.5 Typical section of formwork system ______________________________________ 85 Fig. 2.8.6.1.6 Sequence of PC I-girder fabrication ______________________________________ 86 Fig. 2.8.6.1.7 Workflow for PC I-girder bridges ________________________________________ 87 Fig. 2.8.6.1.8 Direct setting method __________________________________________________ 88 Fig. 2.8.6.1.9 Election Sequence by TEG (1) __________________________________________ 89 Fig. 2.8.6.1.10 Election Sequence by TEG (2) _________________________________________ 90 Fig. 2.8.6.1.11 Election Sequence by TEG (3) _________________________________________ 90 Fig. 2.8.6.1.12 Election Sequence by TEG (4) _________________________________________ 91 Fig. 2.8.6.1.13 Election Sequence by TEG (5) _________________________________________ 91 Fig. 2.8.6.1.14 Election Sequence by TEG (6) _________________________________________ 92 Fig. 2.8.6.1.15 Support system for cross beam works ____________________________________ 93 Fig. 2.9.1 Workflow for Kelani River bridges __________________________________________ 94 Fig. 2.9.2 Construction of temporary bridge and platform ________________________________ 95 Fig. 2.9.3 General section of double sheet pile cofferdam ________________________________ 96

List of Tables

Table 1.3.1.1.1 Working conditions based on type of work and precipitation (p) ______________ 16 Table 1.3.1.3.1 Workable days and operating rate ______________________________________ 17 Table 1.3.2.1 Material conversion factors _____________________________________________ 18 Table 1.3.3.1.1 Production rates for earthworks ________________________________________ 19 Table 1.3.3.2.1 Production rates for paving works ______________________________________ 19 Table 1.3.3.3.1 Production rates for structural works ___________________________________ 20 Table 1.4.1 Critical path activities for the Project based on 48-month schedule _______________ 22 Table 2.6.1.1 Grading requirement for gravel mat and GCP material_______________________ 51 Table 2.7.2.1 Details of quarry areas _________________________________________________ 67 Table 2.7.2.2 Details of borrow pits __________________________________________________ 68 Table 2.7.2.3 Details of dumping sites ________________________________________________ 68 Table 2.8.1.1 List of bridges ________________________________________________________ 71

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SCHEDULE VIII Part 1

1. PART 1: CONDITIONS FOR CONSTRUCTION METHODS

1.1 TECHNICAL PREREQUISITES FOR CONSTRUCTION The construction plan described here in Schedule VIII: Method Statement has been based on the technical prerequisites set forth herein. These technical prerequisites arise from the absolute necessity to carry out the Works as shown below. Without the fulfillment of these technical prerequisites the Contractor cannot physically carry out the Works within the scope of the Contract and to the satisfaction of the Employer. Our financial proposal is also contingent on the fulfillment of these technical prerequisites. We urge the Employer not to treat these prerequisites as a “conditional offer” as per Clause 18.1 of Part 2, Vol. I: Instructions to Bidders. Instead, the Employer’s attention is drawn to the fact that these prerequisites are an absolute must from technical point of view in order to enable the physical possibility of carrying out the Works as supported by technical evidence. 1.1.1

WORK PROGRAMME Location in Contract

Time for Completion

Document Part 4-2: Appendix to Bid –

1,092 days

Time for Completion, Vol. I Please refer to Schedule VI: Work Programme for Bid, and to the present Schedule VIII: Method Statement – Section 1.4 “Description of Critical Path Works”. We have prepared our Work Programme by giving priority to the requirements of Vol. III: Technical Specifications in order to achieve the required quality of the Works. In these Technical Specifications, there are many requirements of Waiting Periods after the completion of certain works such as: a. 1 to 3 months after Gravel Compaction Pile (GCP) b. More than 1 month for preload c. More than 6 months in principle for consolidation settlement by surcharge. Some of the above works are carried out in the same area, which means overlapping of these

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respective waiting periods. In addition, the site handover periods and all other technical requirements of each work item as described in our Method Statement are taken into account in the preparation of the Work Programme. As a result, Type-H soft ground treatment shall be adopted instead of soft ground treatment by “Additional Gravel Compaction Pile” where designated box culvert, abutment and retaining wall in order to avoid above mentioned waiting period and achieves the completion time within 1,092 days. Therefore, our Construction schedule is programmed adopting Type-H treatment but not “Additional Gravel Compaction”.

1.1.2

TEMPORARY ACCESS ROADS

Location in Contract

Presently

Requested Changes

As per right of way (ROW)

As per Schedule VIII: Method

Document Construction Drawings

Statement – Section 2.3.1

The temporary access roads areas given by the Employer as specified in the drawings at some areas are too narrow to allow traffic by heavy construction equipment, namely at the areas of construction of overpass bridges and box culverts. In such places, the Contractor needs additional widths and areas to carry out temporary road construction, otherwise it will be physically impossible to carry out the work. Please refer to the examples in the drawings of this Method Statement – Section 2.3.1 “Temporary works”. 1.1.3

ADDITIONAL POINTS TO BE EMPHASIZED

The following points are clearly set forth in the Contract Documents provided by the Employer. However, these items have great impact on the Work Programme and the proper delivery of the Works. Thus, we would like to highlight them here to emphasize our understanding and reach a mutual agreement with the Employer on them. The Work Programme was compiled based on our understanding of these items as necessary and indispensable prerequisites to enable us to adhere to the construction schedule.

Emphasis Point 1: Handing-over of site dates

TAISEI CORPORATION

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In reference to Part 4-2: Appendix to Bid – Time for granting possession of site, Vol. I: Instructions to Bidders, which was amended by the Addendum dated 21st February 2011 and received by us on 22nd February 2011 (“the Addendum”), the schedule for handing-over of the Site to Taisei has been determined as follows: (a) first section (13+000 – 14+120 and 15+060 – 17+500): 7 days after Date of Commencement (b) Second section (10+500 – 13+000 and 14+120 – 15+060): 3 months after Date of Commencement (c) Third section (A1 Bypass and 8+648 – 10+500): 6 months after Date of Commencement This handing-over schedule is critical for us in order to achieve the construction period of 36 months. Thus, if there is any delay in handing-over the Site in accordance with this schedule, the Engineer must determine the necessary extension of time for completion of the Works (“EOT”) and adjustment of the Contract Price. In reference to Conditions of Contract – Sub-Clause 42.1: “Possession of Site and Access Thereto”, it is necessary to reiterate here that the Employer’s duties are not limited to merely “serving notice to vacate upon owners and user of lands within the right of way of the Contract Works”. The Sub-Clause likewise contains the following necessary implications: -

The construction sites shall be provided to the Contractor by the Employer at the specified time after commencement for each section.

-

The construction site provided to the Contractor shall not be occupied by any remaining residents , squatters, etc., so that the Contractor can commence construction activities without annoyance due to existence of third parties or their property.

Emphasis Point 2: Preliminary survey & soil investigation dates Our Work Programme is based on the dates of possession of site set forth in the three-step site handing-over process described above. Moreover, and as per the Employer Clarification No.02 (page 4 Item 9, and page 6 Item 18), we wish to reiterate the Employer’s commitment that preliminary works such as survey, soil investigation, utilities investigation, etc. can be executed without hindrances prior to the possession of the site.

The dates of these preliminary investigation works are indicated in our Work Programme and the TAISEI CORPORATION

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present Method Statement is based on these dates. Any delay of these dates due to non-fulfillment by the Employer of the above commitment shall have an effect on the Schedule and as such shall entitle us to an extension of time and additional cost. Emphasis Point 3: Utilities diversion under provisional sum We confirm that no specific subcontractor has been nominated by the Employer in the Permanent Diversion of Existing Utility or Service in Provisional Sums. Considering the overall construction schedule requirements, we have fixed the starting dates of these diversion works as shown in our Work Programme. Therefore, the Engineer’s instruction on the Provisional Sum necessary to start diversion work is essential prior to the starting dates shown in our Work Programme. We also reiterate here the clear provisions of 1002.1 “Delays Caused by Utility Agencies”, Section 1000: Provisional Sums, Vol. III: Technical Specifications, namely, if the Contractor has exerted due-diligence, but delays occur due to these relevant agencies, the Contractor is entitled to EOT and relevant costs. Emphasis Point 4: Change of highway lane size from 4-lane to 6-lane In reference to Conditions of Contract – Sub-Clause 52.3: “Variation Exceeding 25 percent”, we would like to highlight the following text: “It (Sub-Clause 52.3) shall not apply where the difference in quantities is the result of a Variation specifically ordered by the Engineer. The provisions of this Sub-Clause shall also not apply to items of work where Detailed Designs have to be done by the Contractor…” The current Drawings and Quantities, and Scope of Works provided by the Employer are based on a 4-lane highway. It is stated in 2. “Location and Objectives”, Part 3: Scope of Works, Vol. I: Instructions to Bidders, that future expansion into a 6-lane highway is planned. We wish to highlight here that such future expansion, if realized, will not be subject to Sub-Clause 52.3 because such expansion will be: -

a variation exceeding 25 percent specifically ordered by the Engineer, and

-

a requirement that the Contractor perform Detailed Design (D/D) of the structures.

Therefore, it is clear from the Employer’s conditions that an expansion to a 6-lane road shall not be considered an increased volume of works, but shall be implemented under a separate contract different and distinct from the current one. The Work Programme and all Method Statements presented here shall not be applicable to any such expansion and there shall be no implication that the TAISEI CORPORATION

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Contractor can or will execute such expansion in accordance with the present project time frame and costs.

1.2 PROJECT DESCRIPTION 1.2.1

INTRODUCTION

The most important point in the execution and completion of the Greater Colombo Urban Transport Development Project, Outer Circular Highway to the City of Colombo – Northern Section-1 is to plan, carry out and complete the work safely and to quality standards in accordance with the requirements given in the Drawings, Specifications and the Terms and Conditions of the Contract, to the full satisfaction of the Employer and the Engineer. In order to achieve the above objectives, sufficient coordination with the Employer and the Engineer should be maintained throughout the project period. We, Taisei Corporation, have a thorough knowledge of highway construction. This knowledge has been acquired through our former experience in the execution and completion of various highways not only in Japan, but also overseas. Based on our thorough experience, we emphasize our ability to safely complete the Greater Colombo Urban Transport Development Project, Outer Circular Highway to the City of Colombo – Northern Section-1 by keeping close coordination with the Employer and the Engineer. The Project consists of the construction of the Outer Circular Highway (hereafter OCH) to the City of Colombo Project, Northern Section-l, from Kadawatha (Sta.8+648) to Kaduwela (Sta.17+500), with length L=8.9km (break: 17m). The construction and consulting service costs are funded by Japan International Cooperation Agency (JICA), Special Terms for Economic Partnership (STEP). 1.2.2

LOCATION AND OBJECTIVES

The OCH is a new full access-controlled circular highway, linking the Colombo-Katunayake Expressway (CKE) and the Southern Transport Development Project (STDP). It is located 10-15km from the City center and is 28.89km in total length (Southern and Northern Sections together). It will connect north and south more quickly as a bypass and disperse traffic from/to Colombo more effectively, resulting in easing traffic congestion in the Colombo Metropolitan Region. The OCH will serve a traffic volume of about 25,000 vehicles/day in 2012 with a 4-lane (each 3.5m wide) highway with a design speed of 80 km/hour. 1.2.3

MAJOR FEATURES OF NORTHERN SECTION-1

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Northern Section-l is the second construction section of the OCH, following the first Southern Section, to connect the Southern Section with the Colombo-Kandy Road (A1 Interchange). It consists of new construction of an access-controlled 4-lane (each lane is 3.5m wide) highway, with length L=8.9km. Major quantities are estimated as follows: •

Materials from quarries

203(8)

•

Materials from borrow pit

203(7)+203(7)-a

•

Disposal of unsuitable material

203(3)

138,340cu.m 39,610cu.m 138,340cu.m

Total material

316,290cu.m

•

Major soft ground treatment

Gravel Compaction Pile (GCP), dia. 700mm

•

Interchange

2 nos.

- A1 (Kadawatha) - Kaduwela •

Pavement: Asphalt wearing and binder courses & aggregate road base and sub-base courses

•

•

Overpass bridge (PC I-girder)

(Total 226m)

5 nos.

- Overpass Bridge No.8 (OB 08)

Sta.9+415


Sta.10+210


Sta.11+261


Sta.12+518.921


Sta.14+843

Incidental works: Guard rails, road signs, markings, lighting, traffic signals, landscaping, etc.

•

Utility relocations: Pylons, electric, telephone and water lines

Conceptual designs for the following permanent works are provided by the Employer. We, Taisei Corporation, will carry out the Detailed Design (D/D) and construct these structures: •

Bridges and viaducts, including interchange ramps:

(Total 4,491m)

At Al Interchange - Main line: Viaduct No.1 (V1)

1 no.

PC I-girder

322m

- Ramp (V5-V8)

4 nos.

PC I-girder

505m

3 nos.

PC I-girder

2,730m

Ramp-2 Bridge: Viaduct No.5 (V5) Ramp-3 Bridge: Viaduct No.6 (V6) Ramp-5 Bridge: Viaduct No.7 (V7) Ramp-6 Bridge: Viaduct No.8 (V8) At Biyagama - Main line (V2-V3,V14&V15) TAISEI CORPORATION

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1st Biyagama Viaduct: Viaduct No.2 (V2) 2nd Biyagama Viaduct: Viaduct No.3 (V3) Viaduct No.4 (V4) At Kaduwela Interchange - Kelani River bridges Main Bridge (HB9)

1 no.

PC I-girder

383m

Access Bridge 1 & 2 (Both sides)

2 nos.

PC I-girder

427m

2 nos.

PC I-girder

376m

2 nos.

PC I-girder

401m

1 no.

PC I-girder

1,307m

- B214 ramp (V9 & V10) Ramp 1: Viaduct No.9 (V9) Ramp 2: Viaduct No.10 (V10) - AB10 ramp (V12 & V13) Ramp 3: Viaduct No.12 (V12) Ramp 4: Viaduct No.13 (V13) - Main line: Viaduct No.11 (V4,V11)

Total: 17 nos. 1.2.4

CONSTRUCTION SCHEDULE

As indicated in Part 1, Section 1.1.1 “Work Programme” of this Method Statement, the construction period of 36 (thirty-six) calendar months specified by the Employer is very tight and challenging. Thus, we must carefully consider the construction method.

1.2.4.1

GENERAL

Taisei Corporation has completed various projects with similar complexity and work details all over the world. The minimum construction schedule is 36 months. We have established this schedule based on a firm and feasible construction method made through proactive studies carried out prior to commencement of the Works. Therefore, we have spent maximum effort to establish a “Method Statement” that we believe is the most appropriate for the Project. We believe that the following three items are key factors for this project in regard with maintaining the construction schedule: •

Preparing and maintaining firm and stable working formation, i.e., equipment platform, on soft ground.

•

Timely implementation of preliminary works, i.e., contractor’s design and utility relocations.

•

Implementation of embankment works at appropriate execution speed.

1.2.4.2

PREPARING AND MAINTAINING FIRM AND STABLE WORKING FORMATION

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The most important key issue in this project is handling soft ground. This is soft ground consisting of thick sedimentation of peat layers, especially at viaduct construction areas. However, employment of large size cranes is inevitable for cast-in-place piling work and girder installation. Therefore, it is very important for schedule control to consider not only permanent highway structures that are built based on the Contract requirements, but also construction of crane working formations (platform) and temporary access roads on soft ground. We recognize that timely construction of stable working formations and temporary access roads can lead to the timely execution of the permanent works. On the other hand, if the working formations and temporary access roads cannot be executed on time or factors such as large displacement during heavy equipment maneuvering due to poor engineering background study, the total construction schedule and the safety of the work will be highly jeopardized. We have acquired a thorough knowledge of handling soft ground and working formations development and temporary access roads construction during our still ongoing project in western Sri Lanka (Southern Transport Development Project, STDP Package 2). We have studied various technical issues, construction methods, etc. enriched by this experience during the tender stage. Regarding viaduct construction, we have planned our working formation and temporary access road as indicated below:

Fig. 1.2.4.2.1 Example of a plan of working formation around bridge piers The access road is set longitudinally beside bridge footings. The width of the access road is 10m so that two pieces of heavy equipment can pass each other. It is necessary to reinforce the soft ground by TAISEI CORPORATION

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placement of gravel and geo-textile sheet for development of working formation. This working formation built in accordance with the above reinforcing measures can be set to the side away from the footing area in the places where it might disturb the piling and excavation works. Regarding the reinforcement of soft ground for temporary access road only, we are highly doubtful of the simplified method of replacement of the soft ground with good material. This method will make it difficult to understand the replaced volume as well as maintain the stability and control the schedule. Furthermore, there is another concern regarding embankment work, i.e., the occurrence of circular failure. A typical section of the working formation is indicated in Fig. 1.2.4.2.2.

Geotextile where necessary for 150t CC

prevention of circular failure

(Top elevation depend flood water level)

Gravel (Crusher run)

0.3-0.5m

Soil

Vary 0-3.5m

0.5-2.0m

Replaced material (Soil)

Boulders where necessary Peat stratum

Geotextile sheet where necessary

Assumed circular failure line to be prevented

Fig. 1.2.4.2.2 Typical section of working formation Placement of geotextile sheet is provided first. This is inevitable to maintain the trafficability of heavy equipment to be used for working formation construction. Then, the material is spread out in such a way as to maintain stability against settlement. Another geotextile sheet with sufficient strength against circular failure is placed on the material. Finally, additional material is placed to form the formation body. The working formation is built in this way. Temporary access roads are also built fundamentally the same way. Load of large cranes on soft ground often creates circular failure and causes various problems in schedule control and safety. This issue can be avoided by the abovementioned geotextile placement. Surface of access roads will be kept 1.5m above natural ground in order to prevent inundation of the road during normal flooding and to shorten non-working period to minimum. This working formation development plan will be verified through trial execution. Based on results derived through trial execution, the firm development method will be fixed, we believe this will contribute to the success of our schedule management.

1.2.4.3

TIMELY IMPLEMENTATION OF PRELIMINARY WORKS

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a. General Regarding bridge construction, nothing is as important as commencing the construction works as soon as possible. This applies for both substructures and superstructures. Detailed designing of bridges and execution of utility relocations are two important items to be completed before commencement of bridge works. We are going to concentrate the design works at the early stage in order to obtain the Engineer’s approval. b. Design schedule We have acquired a thorough knowledge of how to smoothly obtain design approval through our ongoing project in western Sri Lanka, i.e., Southern Transport Development Project, STDP Package 2. We will submit the Detailed Design (D/D) separately in regard to portions of the works instead of submitting a whole design at once. This is to reduce the workload of the Engineer and at the same time shorten each approval period. Thus, design submission will be held on portion-to-portion basis, such as for piling, substructure, superstructure, etc. Eventually, we expect that the Engineer’s approval will be issued for each portion separately. We consider that it will take 7 (seven) days to get the Engineer’s comments on the Contractor’s initial submission, another 7 (seven) days will be required to modify and resubmit the design based on the Engineer’s comments and additional 7 (seven) days are needed to acquire the final approval of the design by the Engineer. Eventually, we consider that it will take a total of 21 (twenty-one) days from initial submission to obtain the Engineer’s approval of the Detailed Design (D/D) for each portion. Once the Engineer’s approval for the Detailed Design (D/D) of a certain portion is acquired, we will commence the construction of that portion immediately. c. Utility relocations Another key factor affecting early start of construction is utility relocations. We fully recognize the importance of utilities as a lifeline of local residents. Therefore, we are going to employ robust and stable structures such as a culvert foundation of water line indicated on the Tender drawing for relocation works, and we will pay our utmost effort to minimize the interruption periods during relocation activities for the sake of eliminating long blackout, water cut-off, etc. Investigation of underground utilities will be basically carried out along the supposed locations indicated on drawings. If unknown underground utility is found at locations other than previously indicated prior to or during the work execution, the work shall be stopped immediately, and the incident shall be reported to the Engineer and relevant authority, and temporary emergency treatment will be provided to the utility found. Then, the Contractor will carry out planning and diversion design, if applicable, together with the relevant authority. The work will be restarted following the Engineer’s approval of the plan. The total cost incurred for such unknown utility shall be paid to the Contractor under Provisional Sum as replied in item No.16, Clarification No.02. TAISEI CORPORATION

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We have considered sufficient time frame of utility diversion as indicated in our Work Programme including discussion period with relevant authorities and the authorities’ working period. Nevertheless, if diversion work cannot be completed within the specified period, the Contractor shall be reimbursed additional cost in addition to EOT specified in 1002.1 “General”, Section 1000: Provisional Sum, Vol. III: Technical Specifications. 1.2.4.4

IMPLEMENTATION OF EMBANKMENT WORKS IN APPROPRIATE EXECUTION

SPEED As for embankment execution, too slow execution will delay the progress while quick execution might cause circular failure and finally deteriorate the quality of the work and delay the progress. Therefore, it is important to carry out the work in a timely manner, with appropriate execution speed, neither slow nor quick, for maintaining the quality and construction schedule. It is quite important to properly predict future settlements before paving work for the sake of eliminating various deteriorations caused by settlement such as cracks on pavement. We have studied thoroughly regarding the relations between planned embankment execution speed and stability of the embankment and also between planned speed and future settlement amount. We have acquired a thorough knowledge of these phenomena through ongoing project in western Sri Lanka (Southern Transport Development Project, STDP Package 2). Thus, we are fully confident in our current plan. We believe that additional soil investigation to be carried out after award of the project will enforce the preciseness of our plan and the feedback from actual monitoring results during execution can significantly contribute to both construction schedule control and quality control. 1.2.5

ENVIRONMENTAL MANAGEMENT PLAN (EMP)

The Northern Section-1 is located mostly in marsh and abandoned paddy fields. We will pay sufficient attention not to produce any air and water pollution, noise and vibration during the construction. At the same time, we will keep good relations with neighbouring residents, including the convenience of access and temporary roads. In the whole process regarding environment, Taisei Corporation will follow the Environmental Management Plan (EMP) in the Tender documents, as well as the various regulations and instructions included in the Central Environmental Agency’s (CEA) approval letter (included in Data provided by the Employer). It is our fundamental desire to maintain the splendid atmosphere of the outer suburb of Colombo and to limit the effects of highway construction on the environment to a minimum. We have decided not TAISEI CORPORATION

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to change any routes of natural brooks or streams from their original locations. Thus, we are going to install pipes not only in the permanent structures but also in our temporary access roads. In addition to the abovementioned countermeasures for flood, we plan to install temporary staging as shown in Fig. 1.2.5.1. This staging will be applied specifically at viaduct areas, because the geological condition of these areas is very weak and many heavy types of equipment, such as 150t cranes have to pass continuously for piling work and superstructure work. Location and number of these bridges should be decided as per the actual site condition.

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Fig. 1.2.5.1 Example of temporary staging for flood TAISEI CORPORATION

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We are concerned about the low potential of hydrogen, PH4, of peat strata found in some area. Exposed peat will cause unfavorable odor to surroundings and might be a cause of future water contamination. We would like to discuss with the Engineer regarding this matter after the Contract award. One of the countermeasures considered is to dispose the peat into hollows derived from brick clay mining existing here and there and cover them by topsoil (refer to Fig. 1.2.5.2). It will not only solve the issues of the low potential of hydrogen, but also eliminate water pools after rain that bring incidence of mosquitoes and epidemics.

Hollow derived from brick clay mining

Topsoil

Topsoil

Disposed peat

Fig. 1.2.5.2 Disposal of peat into hollow and covering it by topsoil 1.2.6

SAFETY AND PUBLIC RELATIONS

We believe that all accidents can be avoided if appropriate procedure is taken by suitable workforce with sufficient safety consciousness and well maintained proper equipment. Soon after receiving the Contract award, we will establish a Safety manual specific to this project. All construction activities shall strictly follow this manual. Some of the key elements we are going to employ include the following: 1. Daily risk assessment meeting 2. Safety training provided for all personnel involved

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3. Establishment of safety management with daily, weekly and monthly routine cycles 4. Establishment of monthly safety awarding system 5. Enforcing strict safety rules for preventing accidents by equipment, falling, etc. 6. Providing sufficient number of warning signs or keep off signs for dangerous areas, clear indication of temporary access roads, etc. 7. Providing periodic safety patrol by staff of Safety department and Engineering department of International Operations Headquarters 8. Establishment of strict safety rules for blasting, if applicable, such as specified protective measures or fixing the evacuation distance 9. Providing various measures to avoid accident involving a third party, such as employing traffic controller at all intersections of temporary access roads with public roads 10. Explanation to adjacent residents including key persons of the region regarding danger in the construction site 11. Establishment of an honest compensation system in case of an accident 12. Providing sufficient safety protection goods including helmet, safety shoes, safety jackets, etc. for all workforce involved 13. Provision of strict safety training for newcomers 14. Establishment of a monthly safety meeting. Workers shall point out hidden factors of accident to each other. Thus, self-safety consciousness is increased. 15. Occasional safety patrol by owners of specific Subcontractors 16. Routine checking of staging and scaffolding around structures We believe it is very important to acquire local residents’ supporting attitude toward the Project. We plan to support the Employer through the development and implementation of public relations. Based on approval by the Engineer, we will have occasional meetings with local residents to explain the intent and meaning of the Project together with construction activities carried out for the sake of avoiding accidents involving a third party.

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1.3 PROCESS CONDITIONS 1.3.1

WORKABLE DAYS

In order to determine the operation rate of the Project, weather conditions, holidays in Sri Lanka and type of work are taken into account for the site location. 1.3.1.1

WORKING CONDITIONS BASED ON TYPE OF WORK AND PRECIPITATION

Precipitation data at the Homagama Station were investigated for a 10-year period, from 1999 to 2009. Since especially recent precipitation is stronger than earlier one, we use recent data of the last 5 years (2005 – 2009) in the analysis of operating rate (see Table 1.3.1.3.1). Daily precipitation (p) data are grouped into 4 (four) categories, while main works of the Project are classified into 3 (three) types, as shown in Table 1.3.1.1.1. From our past experience we consider the number of days lost and the status of operation based on precipitation p for each type of work as follows: Table 1.3.1.1.1 Working conditions based on type of work and precipitation (p) Rainfall (mm/day)

Work loss (day)

Type of work Earthworks/ Paving works

p≦1.0

1.0
10
30
0.0

0.3

1.0

2.0

Operation suspended

Operation suspended

0.3

1.0

Normal operation

Operation temporarily suspended

0.0

0.0

Normal operation

Normal operation

0.0

0.0

Normal operation

Normal operation

Piling works

Other works

1.3.1.2

Operation temporarily suspended 0.3 Operation temporarily suspended

Operation suspended 1.0 Operation suspended

HOLIDAYS IN SRI LANKA

In this proposal, 77 (seventy-seven) rest days are considered in a year. These rest days comprise all Sundays and holidays (refer to Table 1.3.1.3.1). 1.3.1.3

WORKABLE DAYS AND OPERATING RATE

Combining the rest days and rainfall data, the number of workable days for each month is calculated and then the operating rate is determined, presented in Table 1.3.1.3.1: TAISEI CORPORATION

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Table 1.3.1.3.1 Workable days and operating rate Month

Remarks

Jan

Feb

Mar

Apr

May

Jun

Jul

Aug

Sep

Oct

Nov

Dec

Annual

Days

31

28

31

30

31

30

31

31

30

31

30

31

365

Rest days

8

7

5

8

7

5

6

5

5

8

5

8

77 Average

Workable days (day/month) considering unworkable days due to rain only Earthworks/ 23

24

22

15

15

15

22

19

16

10

8

22

17.3

28

27

28

25

26

25

28

27

25

23

21

28

25.5

Paving works Piling works/ Other works Annual

Operating rate (%) considering unworkable days due to rain only Earthworks/ 73%

85%

70%

50%

49%

50%

70%

61%

54%

34%

28%

71%

58%

90%

95%

90%

82%

83%

83%

91%

86%

84%

73%

71%

90%

85%

Paving works Piling works/ Other works Workable days (day/month) considering unworkable days due to rain & rest days*1)

Average

Earthworks/ 17

18

18

11

12

12

17

16

13

8

7

16

13.6

21

20

23

18

20

21

23

22

21

17

18

21

20.1

Paving works Piling works/ Other works Operating rate (%) considering unworkable days due to rain & rest days*1)

Annual

Earthworks/ 54%

64%

58%

37%

38%

41%

56%

51%

45%

25%

23%

53%

46%

67%

71%

75%

60%

64%

69%

73%

72%

70%

54%

59%

67%

67%

Paving works Piling works/ Other works

↓ Modified operating rate (%) applied in planning Unworkable days/

Rest days/month

Unworkable days/

Workable

month (due to rain)

(non-rainy days)

month (total)

days/month

14.3

3.7

18.0

12.0

40%*2)

Piling works

4.6

2.9

7.5

22.5

75%*3)

Other works

4.6

4.4

9.0

21.0

70%*4)

Earthworks/ Paving works

Annual

*1) Some rest days are also rainy days; therefore the number of rest days is reduced *2) Modified operating rate is based on our ongoing experience in Sri Lanka: 46% is reduced to 40% *3) Half of rest days are considered as working days: (85%+67%)/2 *4) One rest day is considered as working day to ensure the planned construction schedule: +3% TAISEI CORPORATION

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1.3.2


MATERIAL CONVERSION FACTORS

In our estimation and planning, we employed the material conversion factors in Table 1.3.2.1: Table 1.3.2.1 Material conversion factors Material

Original condition

Converted condition Ground

Loosened

Compacted

Ground

1.00

1.20

0.93

Ground

1.00

1.25

0.90

Ground

1.00

1.30

1.15

Ground

1.00

1.60

1.25

Ground

1.00

1.65

1.40

Soil Classified material Borrowed material Unsuitable material Soft rock (Excavation) Hard rock (Excavation) Quarry material

1.3.3

PRODUCTION RATES

All production rates prepared by Taisei Corporation are based on our assumptions; therefore actual production rate values may differ from those indicated in the followings.

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1.3.3.1


EARTHWORKS Table 1.3.3.1.1 Production rates for earthworks

Type of work

Detail

Classified material for reuse

Equipment Backhoe 0.9cu.m class Bulldozer 15.85t class

Productivity ( /day・・no) 425 cu.m

Bulldozer 41.2t class with Excavation Hard rock material for reuse

Ripper Crawler drill (hydraulic)

80 cu.m

150kg class Unsuitable material Roadbed of embankment

Fill

Bulldozer 15.85t class Vibratory roller 12.5t class

Cut slope

Backhoe 0.4cu.m class

160 sq.m

Fill slope


120 sq.m

Grading

Grader 3.7m class

Spreading & compaction

Band drains

Compacted general

Vibratory roller 12.5t class

Bulldozer 15.85t class Pile driver for band drain

Gravel size: max. 50mm

Bulldozer 15.85t class

Spreading & compaction

Vibratory roller 12.5t class

Gravel size: max. 50mm

fill 1.3.3.2

400 cu.m

Bulldozer 43.2t class

Tire roller 8-15t class

Gravel mat

200 cu.m

Soft soil excavation (using quarry material)

Slope formation

Subgrade


Crawler type pile driver 50t class

480 cu.m

3,300 sq.m 1,500 sq.m 1,700 m 830 cu.m 210 m

PAVING WORKS Table 1.3.3.2.1 Production rates for paving works

Type of work

Detail

Equipment

Productivity ( /day・・no)

Motor grader 3.1m class Subbase

(with Vibratory roller 8t class &

3,600 sq.m

Tire roller 8-15t class) Asphalt paver Aggregate road base

(with Vibratory roller 8t class &

3,000 sq.m

Tire roller 8-15t class)

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Asphalt paver 2.5-6.0m class

Asphalt concrete

(with Macadam roller &

binder course

600 tonne

Tire roller 8-15t class) Asphalt paver 2.5-6.0m class

Asphalt concrete

(with Macadam roller &

wearing course

600 tonne

Tire roller 8-15t class)

Portland cement

Slipform paver 2.0-6.0m class

concrete pavement 1.3.3.3


500 sq.m

BRIDGEWORKS Table 1.3.3.3.1 Production rates for structural works

Type of work

Detail

Common excavation

Equipment Backhoe 0.7cu.m class Backhoe 0.7cu.m class

Soft rock excavation

+ Hydraulic breaker Both RCD and AC piling methods

Bored pile *2)

Rebar Formwork

Productivity ( /day) 210 cu.m 30 cu.m 6.5 m/h soil

Reverse Circulation Method (RCD)

0.250 m/h rock *1)

All Casing Method (AC)

0.250 m/h rock *1)

Earth Drilling Method (ED)

165.0 m/13h

Base slab

Track crane 25t class

2.0 tonne

Wall/Column


2.5 tonne

Base slab


30 sq.m

Wall/Column


25 sq.m

(Installation & dismantling)

Base slab/

Concrete placing

PC I-girder installation

Wall/Column

Concrete pump 90–110cu.m/hr

I-girder

Pump, bucket & crane

Crane erection

Crawler crane 150t class x 2

300 cu.m (max) 85 cu.m (max) 4 nr.

*1) We estimate rock unconfined compressive strength 50MPa based on the Tender document. *2) Productivity of bored pile is the drilling speed.

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1.4 DESCRIPTION OF CRITICAL PATH WORKS Refer to the submitted Work Programme for details regarding the construction schedule. Critical path activities are given in sequence, for clarity. We prepared the Work Programme in which the whole Work will be completed within 36 (thirty-six) months, based on bidding documents such as drawings, including Topographic Survey Data, Technical Specifications, Data Provided by the Employer, etc. In addition, major assumptions to the Soft Ground Treatment Type-A to G area that the Work Programme is based on completion within 36 months are as follows: 1. The Contractor’s possession of the Site is implemented in three steps, i.e., within 7 days after the Date of Commencement, exactly 3 calendar months from the Date of Commencement and exactly 6 calendar months from the Date of Commencement. The last point in each time frame is employed (Page 27, Part 4-2: Appendix to Bid, Vol. I: Instructions to Bidders & Addendum No.02). 2. Stabilizing leaving period after the GCP execution is fixed to 1 calendar month. The earliest point of the time frame is employed (Page 33 of 50, 3.3 Gravel Mat and Gravel Compaction Pile, Section 204: Soft Ground Treatment, Vol. III: Technical Specifications). 3. Preloading leaving period is fixed to 1 calendar month. The earliest point of the time frame is employed (Page 33 of 50, 3.3 Gravel Mat and Gravel Compaction Pile, Section 204: Soft Ground Treatment, Vol. III: Technical Specifications). 4. Surcharge leaving period is fixed to 6 calendar months. The earliest point of the time frame is employed (Page 36 of 50, 3.6 Surcharge, Section 204: Soft Ground Treatment, Vol. III: Technical Specifications). Critical path works in our 36-month Work Programme are indicated in Table 1.4.1 and Fig. 1.4.1. This Work Programme and these critical path works are based on the above assumptions. Thus, it should be emphasized that the Programme and the critical path may differ depending upon any changes in the above-mentioned assumptions 1 through 4 (such as extended preloading and surcharge leaving periods), additional ground investigation and boring data, soft ground treatment testing and site survey, etc.

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Table 1.4.1 Critical path activities for the Project based on 36-month schedule Critical path activities for the Project (1) Activity ID*

Section

1

3

KEY DATE

COMMENCEMENT

0

2

62

Instruction for Diversion of Existing Utilities by the Engineer

0

0

3

68

Planning of Diversion of Existing Utilities for Section 3,4,5 & 6

79

79

4

64

5

65

No.

GENERAL

Task

Duration of task Critical duration (day) (day)

Remarks

0

Planning of Diversion of Existing Utilities for Section 1 & 2

78

78

Discussion and Approval from the Authorities concerned

14

14

6

66

Discussion and Approval by the Engineer

14

14

7

166

Diversion of Existing Utility

90

90

8

168

Clearing & Grubbing

30

30

9

187

Gravel Mat

120

60

10

189

Compacted General Fill

60

60

11

185

Geotextile

125

95

Overlapping with ID No. 188

12

186

Band drain

125

95


13

188

Gravel Compaction Pile φ700 (Incl. Leaving period of One Month)

125

95

14

178

Fill for Road-bed of Embankment @ SGT Area

270

270

15

180

Surcharge Duration(incl. Engineer's approval)

255

215

16

183

Subgrade with Selected Material or Capping Layer

332

30

17

192

Sub-base Course for Flexible Pavement

340

22

18

194

Aggregate Road Base

340

9

19

195

Prime Coat

210

15

20

197

Asphalt Concrete Binder Course

210

15

21

196

Tack Coat

210

15

22

198

Asphalt Concrete Wearing Course

210

15

23

284

INCIDENTAL WORK

240

30

24

285

FACILITY WORK

240

30

25

4

0

0

3,107

1,096

SECTION 2 (Sta.8+970Sta.10+500)

KEY DATE

COMPLETION

Total


Parallel with ID No. 284

* Refer to Schedule VI: Work Programme for Bid

Critical path activities for the Project (2)

No.

Activity ID*

Section

1

3

KEY DATE

2

40

Instruction for Additional Soil Investigation

0

0

3

41

Planning of Additional Soil Investigation

30

30

4

42

Discussion & Approval by the Engineer

21

21

5

50

Additional Soil Investigation for Structure (HB9,V4 & Ramp)

70

70

6

472

Detailed Design of Concrete Bridge

150

42

7

473

Approval by the Engineer

21

21

8

534

Test Pile

100

100

9

557

Bored Piling

100

100

10

558

Excavation (incl. Temporary Shoring)

180

120

11

559

Substructure

180

30

12

538

Substructure

130

100

13

552

Substructure

123

75

14

544

Excavation (incl. Temporary Shoring)

60

60

15

545

125

125

16

546

29

29

17

553

28

28

18

547

Deck Slab

30

30

19

554

Deck Slab

30

30

20

548

Waterproof/Pavement

90

90

21

555

Waterproof/Pavement

90

90

22

467

Tack Coat

150

60

23

469

Asphalt Concrete Wearing Course

150

5

24

604

INCIDENTAL WORK

207

30

25

605

FACILITY WORK

207

30

26

4

1.GENERAL

Task COMMENCEMENT

SECTION 6 Substructure (STA.15+060~ST Girder Erection A.17+500) Girder Erection

KEY DATE

COMPLETION

Total

Duration of task Critical duration (day) (day) 0

Remarks

0

0

0

1,904

1,096




* Refer to Schedule VI: Work Programme for Bid

TAISEI CORPORATION

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Fig. 1.3.3 Work Programme – Critical Path Activities

TAISEI CORPORATION

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1.5 PARTICULAR CONCERNS 1.5.1

HANDOVER PROCEDURE

Upon substantial completion of any part or section of permanent works, we, Taisei Corporation will arrange the necessary requirement for the handing over procedure. At any time such part or section of the Works has passed all tests and has been satisfactorily accepted by the Engineer, authorized representatives of both parties will duly certify the Joint inspection sheet. The Project manager will manage his subordinates and deal directly with the Engineer to conduct a joint inspection for any part or section of the Works which had been substantially completed, on the agreed date and in the presence of the Engineer’s representative. The joint inspection will consist of: 1. Specific testing method 2. Commissioning test 3. Defects inspection 4. Maintenance regimes 5. Provision of spares 6. And any other test(s) required under the conditions stipulated in the Contract. The Project manager is responsible for the handing over procedure, for which it is necessary to: 1. Prepare the format of Joint inspection sheet 2. Prepare punch list and notice of his intention to conduct the test or inspection on a specific date and time 3. Carry out the test or inspection for handing over on the date agreed and in the presence of the Engineer 4. Forward to the Engineer duly certified copies of the Joint inspection sheet 5. Formally request the Engineer to issue the Taking-over certificate, stating the date when the Works become substantially completed. The flowchart for handing over procedure is shown in Fig. 1.5.1.1 for further reference.

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Engineer


Taisei Corp.

Cleaning

Inspection

Yes

Inspection No

Application Punch list

Application No

Repair, remedy

Repair, remedy

Inspection Yes Approval

Issuance of Taking-over Certificate

Handing over

Fig. 1.5.1.1 Handover procedure

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1.5.2


DEFECTS LIABILITIES

We will establish a firm organization during the defect liability period of 365 (three hundred and sixty-five) days to carry out any remedial works, which may arise in this period and also such outstanding items of the Works as are listed in the Taking-over certificate. This organization for the defect liability period consists of senior engineers for civil works, mechanical works, electrical works and quality assurance. The assignment of each senior engineer will be discussed with the Employer and the Engineer in order to be approved. The role and responsibilities of these engineers are as follows: 1. To take overall quality management and coordination of remedying works; and 2. To be responsible for any defect item regarding civil, mechanical and electrical works. If any defect item is found by us or informed by the Employer, the item will be investigated by the Quality engineer, and be categorized into each work scheme. The senior engineer in charge of the work scheme is assigned to remedy the defects and outstanding items. He will immediately contact his staff and the Subcontractor and let them perform the remedy work to the satisfaction of the Employer and the Engineer. The flowchart of remedy work during the defect liability period is shown in Fig. 1.5.2.1:

TAISEI CORPORATION

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Engineer

Taisei Corp.

Notice

Person in charge

Inspection Method

Report to Head Office

Yes

Inspection Approved method of repair

Application for inspection No

Repair, remedy

Inspection Yes Approval

Request for Defect Liability Certificate

Issuance of Defect Liability Certificate Completion

Fig. 1.5.2.1 Remedy work during the defect liability period

TAISEI CORPORATION

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2. PART 2: CONSTRUCTION METHODS WITH CONSTRUCTION RESOURCES

2.1 GENERAL We, Taisei Corporation, believe that it is our duty to complete the Works conforming to the relevant Drawings, Specifications and other requirements described in the Contract documents and to carry out the Works following any local laws and regulations, paying utmost care for environmental and safety issues for the sake of obtaining the utmost satisfaction of the Employer and the Engineer. We would like to execute the Project based on our previous experience in highway construction projects, both in Japan and overseas and also our experience in project implementation in Sri Lanka.

2.2 OVERALL WORKFLOW The whole project site is divided into 6 (six) working sections as indicated in Fig. 2.2.1. Major earthwork material and filling material are directly delivered to the execution site in order to diversify hauling vehicles and therefore to mitigate traffic jams. Temporary construction road is provided along the highway alignment. Construction materials such as concrete or asphalt, heavy equipment, etc. are transported by using this temporary construction road so as to minimize public roads usage from the point of view of environmental protection. For the sake of project implementation it is necessary that all works are well coordinated with each other in a manner satisfactory to the Employer and the Engineer. Construction method of each work item is described in the followings.

TAISEI CORPORATION

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Exactly 6 months from the Date of Commencement


SECTION 1

Sta.8+648 V1 OB 08 (Sta.9+415)

SECTION 2 Exactly 6 months from the Date

V14

of Commencement

OB 09 (Sta.10+210)

A1 B169

Sta.10+500

B262

V15

OB 10 (Sta.11+261)

SECTION 3 B221

Excactly 3 months from the Date of Commencement OB 11 (Sta.12+518)

Sta.13+000

SECTION 4 Exactly 7 days after the Notice to Commence

V2 Sta.14+120

SECTION 5

Box Culvert Sta.14+619

Exacaly 3 months from the Date of Commencement OB 12 (Sta.14+843) Sta.15+060 V3

B214

SECTION 6 Exactly 7 days after the Notice to Commence

AB10 V4 & HB9 & V11

Sta.17+500

OCH Northern Section-1 (L=8.9+1.9km) VIADUCT (L=6.1km)

OB = Overpass Bridge

Box Culvert

V = Viaduct

Fig. 2.2.1 Overall project plan

TAISEI CORPORATION

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The Work area is divided into 6 (six) different sections as shown in Fig. 2.2.2. Work at each section shall start immediately following the site possession. Refer to Section 1.1.3 "Additional points to be emphasized” of this Method Statement for further details.

Temporary site offices and facilities

Section 6

(Sta.15+060–Sta.17+500) Notice to Commence

(Sta.14+120–Sta.15+060) Date of Commencement

Within 7 days after the

Section 5 Exactly 3 months from the

(Sta.13+000–Sta.14+120) Notice to Commence

Section 4 Within 7 days after the

(Sta.10+500–Sta.13+000)

(Sta.8+648–Sta.10+500) Date of Commencement

Date of Commencement


Section 3

A1 Bypass Date of Commencement

Exactly 3 months from the


Temporary access roads

Fig. 2.2.2 Work division into working sections

TAISEI CORPORATION

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For each section, work will be carried out as shown in the flowchart in Fig. 2.2.3.

Preliminaries

Temporary access road construction

Clearing and grubbing, removal of structures, utility relocation works

Soft ground treatment procedures (if required)

Box culverts

Foundation pile

Substructure

Fill for embankment

Surcharge (as soft ground treatment procedure)

PC I-girder

Subbase course and Aggregate road base

Slab work, etc.

Asphalt course

Incidentals and Facilities

Fig. 2.2.3 Overall workflow

TAISEI CORPORATION

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2.3 COMMON WORK ITEMS 2.3.1

TEMPORARY WORKS

a. Temporary road construction Temporary construction roads and crane working formations are developed prior to main work execution in order to haul earth material and provide stable crane operation. These construction roads and working formations are constructed along the highway alignment. Most of the working formations and temporary roads are constructed on soft ground. Therefore, firm roads and working formations are prepared in order to maintain smooth traffic and stability. Width of temporary road is 8m for earthwork area and 10m for viaduct area. Periodic rectification of uneven surfaces is carried out by using motor grader. Crushed stone is provided at settled areas if needed. Water sprinkling is provided by using water lorry to prevent dust pollution. Temporary pipe culvert is provided at river crossing areas. Traffic controllers are assigned and notice boards, barricade, etc. are provided for intersection with existing roads or diversion roads. The temporary construction road is to be built along the whole section of the main road. This temporary construction road shall be a rigid one considering maneuverability and traffic volume of construction vehicles. The main road alignment is located mainly on marshy areas. Eventually, the temporary construction road will obstruct natural water flow during flood. Therefore, temporary drainages and bridges will be provided in embankment areas of the temporary construction roads so as to allow the floodwater to flow in similar manner to the main road (refer to Fig. 1.2.5.1). In the Drawings the ROW area given by the Employer is specified, where temporary access roads can be built. However, this ROW at some areas is too narrow to allow traffic by heavy construction equipment especially at the areas of construction of overpass bridges and box culverts. In such places, we will require additional width and areas for the sake of temporary roads construction otherwise it will be physically impossible to carry out the work. Refer to examples in Fig. 2.3.1.1 and Fig. 2.3.1.2. Additional drawings for each area of construction of the overpass bridges and box culverts where the temporary road will exceed ROW shall be provided after contract signing.

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Fig. 2.3.1.1 Example of temporary road outside ROW (box culvert) TAISEI CORPORATION

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Fig. 2.3.1.2 Example of temporary road outside ROW (overpass bridge) TAISEI CORPORATION

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b. Diversion road construction Diversion roads are constructed to maintain traffic on major roads during the execution of the Project. Dimensions of diversion roads are similar to those of original roads. Temporary land acquisition is executed in case the diversion road is constructed outside the ROW. In the case of existing roads being used as diversion roads, required rectification such as widening, etc. is provided. Traffic controllers are assigned and notice boards, barricade, etc. are provided for the sake of smooth traffic, and water sprinkling is provided by using water lorry to prevent dust pollution. 2.3.2

UTILITY RELOCATION WORKS

a. General In the Bidding documents, there are 3 (three) types of utilities: electrical power lines by the Ceylon Electricity Board (CEB), water supply by the National Water Supply & Drainage Board (NWS & DB) and telecom line by the Sri Lanka Telecom (SLT). These utility relocation works directly affect the critical path. Management and coordination with each agency are very important. After having received from each utility agency instruction to relocate the permanent position, we can start the actual planning for relocation. Relocation scheme is as follows: 2-step relocation scheme Step 1 – Preparation work for permanent utility relocations (if necessary) Step 2 – Final permanent utility relocations b. Scope of Work CEB Overhead Power Transmission Lines: - Power line of 35kV or more and sub-line systems including pylons - Intermediate power transmission line of 3kV to 35kV - Low voltage power distribution line of 400V/230V after transformer substation - Transformer stations distribution capacity of 500kVA to 1500kVA - Transformer stations distribution capacity less than 1500kVA SLT Telephone Lines: - Overhead line or underground metallic or fiber-optic cables NWS & DB Underground Water Pipes: - Water distribution mains and transmission mains 1) Less than 100mm diameter 2) 100 mm to 1000mm diameter - Water Services - Property water services 20mm or larger

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2.3.3


EXCAVATION, EMBANKMENT AND HAULING WORKS

Earthwork is the major work item of the Project. All earthwork will be executed in accordance with the relevant Specifications and Drawings. The detailed execution method statement for each earthwork item will be submitted to the Engineer for approval prior to commencement. Felling, clearing and grubbing are carried out prior to main earthwork. All topsoil is removed to a depth of 20cm. Removed topsoil with high water content is dried under the sun and then hauled to designated dumping site. Backhoe (0.8cu.m class) is used for clearing and grubbing. Felled trees are stocked at designated locations. Removal of existing structures takes place. Considering the existing conditions, structures to be removed are thought to be drainage facilities, pavements, road facilities, buildings, fences, guard rails, telephone poles, traffic signs, etc. These, depending on the type of objects to be removed, are demolished and removed by backhoe (0.8cu.m class), with or without breaker. Then, unsuitable waste material is to be hauled to the designated dumping site, while suitable waste material, e.g. crushed stone, etc., is used, for example for the embankment of construction roads. After removal of existing structures, backfilling and leveling of the Site take place. Excavation and embankment works are carried out following clearing and grubbing, as well as the removal of existing structures. Common soil is excavated mechanically by using backhoe (0.8-1.4cu.m class) and/or bulldozer (15-42tonne class), and is transported by dump trucks (8-15tonne class). As for excavated materials, suitable ones are used for embankment or backfilling, while unsuitable ones are hauled to the designated dumping site. In regard to rock excavation, we decided not to use ordinary explosives because of surrounding circumstances and total volume of rock excavation. We planned to use non-explosive demolition agent instead of explosives, as this method will not cause big blasting noise. Broken rock mass is collected by bulldozer (42tonne class), and then loaded onto dump truck (8tonne class) by using backhoe (1.4cu.m class). Borrow material conforming to the Specifications is delivered from outside the site. Filling material, borrow material and excavated suitable materials are transported to the embankment site in order to be spread uniformly in thin layers (conforming to the Specifications) and compacted. Water content of filling material is adjusted by water sprinkling, by using water lorry. Excavated rock material is placed in layers equal to the average rock dimension conforming to the Specifications. Rock spreading is carried out by using bulldozer (32-42tonne class). During spreading filling material, specific care is taken so as not to damage the previous compacted layer. Rock layer is compacted by using vibratory roller (8tonne class).

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Throughout the execution of earthworks, the following points are always monitored and checked from the point of view of quality control: a. Excavation •

Excavated base is not disturbed

•

Rainwater and other water encountered is always drained thoroughly

•

Excavated bases are kept as dry as possible

•

Excavated bases are always smooth and uniform

b. Embankment •

Embankment layers is spread to the specified thickness and compacted with appropriate moisture content to achieve the specified density

•

The following items will not be allowed to become mixed up with the embankment material: -

Organic matters

-

Debris

-

Trees, stumps and roots

c. Hauling works •

Hauling vehicles strictly follow the local traffic rules and all regulations established by the Safety division of the site organization

2.3.4

DRAINAGE WORKS

a. River canal relocation at Rakgahawatta We will relocate the Rakgahawatta Ela as shown in the Drawings (Sta.15+915). This work consists of excavation/filling and construction of rubble masonry sidewalls in accordance with the levels, sizes and dimensions given on detail drawings.

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b. Pipe culverts A typical section of pipe culverts and construction sequence with details is given in Fig. 2.3.4.1.

Preparation works and concrete pipe

BD > DN + 2t + 2 x 0.5 m

Excavation and bedding Pipe culvert t

DN

Pipe culvert installation

t Selected backfill material

Backfilling Fig. 2.3.4.1 Typical section of pipe culverts and construction sequence •

Concrete pipes are manufactured according to the Specifications and Drawings. The concrete pipe manufacturing process is accessible to the Engineer for inspection in order to ensure that the product meets the required specifications.

•

Excavation is done by backhoe (0.8cu.m class), which loads the soil on dump truck to be hauled away. Excavation width is taken as to ensure at least 50 cm from the outer side of each side of the pipe. Good compaction is done to bedding layer beneath the pipe. After compaction, the level of bedding is confirmed and reported to the Engineer for approval. The pipe is then installed.

•

Pipes are inspected just before installation to ensure no damage is present. The Engineer’s approval is then requested before installation of the pipe. Installation is done by crane (25tonne class) with a capacity suitable to the diameter of the installed pipe. For jointing pipes, mortar is applied on the peripheral section of the previous pipe before installing the following one to ensure adherence between the two pipes. After jointing pipes, surplus mortar in the inside of pipe is cleaned. The mortar on the outside of pipe is cured for two days by an appropriate method before backfilling.

•

Backfilling material is brought to site on land by dump trucks. It is made sure that no stone with a size of 25mm or above is present in the backfilling material, and such stone is cleared from backfilling soil if found before backfilling. Backfilling is done by backhoe (0.8cu.m class), which mounds the soil while taking care not cause any damage to the pipes. Compaction is done after each layer of approximately 20cm of backfill.

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c. Ditches A typical section of ditches and construction sequence with details is given in Fig. 2.3.4.2.

Riprap stone

Mortar

Excavation and bedding

Installation of riprap stone

Filling with mortar Fig. 2.3.4.2 Typical section of ditches and construction sequence Excavation is done in a similar manner to the excavation for reinforced concrete pipes described previously. Excavation dimension is equal to the ditch type drainage to be constructed, without any over-excavation. After compaction, the level of the bedding is confirmed and reported to the Engineer for his approval. •

Wide and flat stones are chosen with their larger faces roughly rectangular and parallel to each other. Thickness of stone is 30cm (measured perpendicular to the faces of the stone). Front top face is lined to the required line and grade. All spaces under the stone are filled and tamped with the same material as the bed course.

•

Stones are laid with closed joints and filled with mortar as specified. Mortar is composed of onepart cement and two-part sand by dry loose volume, and suitable amount of water to make a mortar that can be easily handled and trowelled.

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d. Catch basins Fig. 2.3.4.3 shows a typical section of catch basins and construction sequence with details.

Cover

Excavation and bedding for catch basins

Gravel layer and blinding concrete Construction of catch basin (formwork, concreting)

Concrete Reinforcement

Backfilling Fig. 2.3.4.3 Typical section of catch basins and construction sequence •

Excavation is done in a similar manner to the excavation for reinforced concrete pipes described previously. After compaction, the level of bedding is confirmed and reported to the Engineer for his approval.

•

Gravel is transported to site on land, by using dump trucks. A backhoe (0.8cu.m class) mounds and spreads the material. Compaction is done by using compacting machines. After spreading and compaction, the shape of foundation’s gravel layer is checked and thickness is inspected. Blinding concrete is cast directly by using chutes fixed to the concrete mixer.

•

All reinforcing bars are cleaned from all foreign material (if any) adhered to the bars. Bars are correctly assembled according to the Drawings by spacers to ensure the specified concrete cover thickness. Formwork is assembled and firmly fixed by chains and turnbuckles to ensure no movement or bulging occurs during concreting. Concrete is cast continuously by using concrete pump to avoid cold joints and sufficient number of vibrators is used to ensure good compaction. Curing with water spraying is carried out for the necessary period. The Engineer’s approval is requested for the finished product and amendments are made if necessary.

•

Backfilling is carried out in a similar manner to the previously described backfilling of reinforced concrete pipe culverts.

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2.3.5


PAVING WORKS

a. Preparation for subbase (selected material of 20cm thick layer) After surcharge placement is carried out, leaving off period for settlement takes place, based on the result of settlement monitoring. After receiving the approval of the Engineer, surcharge is removed and preparation of subbase is carried out. Subgrade is that part of the work on which the subbase is placed or, in the absence of subbase, it acts as the base of pavement structure. It extends to the full roadbed width, including shoulders and lay-byes as indicated on the Drawings. Materials are acceptable earthwork materials conforming to the classification and compaction requirements of Section 203: Excavation and Embankment, Vol. III: Technical Specifications.

Embankment

- Surplus material is excavated and removed to designated places and/or to stockpile yard. Leveling is conducted by motor grader.

Leveling by motor grader

- Suitable water spraying is conducted up to Spraying water

the optimum water content state and compaction is done.

- Compaction is done by vibratory roller and

Compaction by roller

tire roller until obtaining the density required in the Specifications. Subgrade is stabilized to allow placing a subbase material without Subbase course

rutting or displacing the roadbed.

Material transportation:

Spreading:

1st compaction:

2nd compaction:

Dump truck

Motor grader

Vibratory roller

Tire roller

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b. Subbase course Subbase course is constructed as an under course to the aggregate road base, shown in the flowchart below. Pavement structure, where subbase course is used is shown in Fig. 2.3.5.1:

Fig. 2.3.5.1 Pavement structure (subbase course)

Subgrade preparation Material transportation

- Materials are cleaned of any mud or other foreign substances. Spreading and leveling is done by motor grader. Finishing thickness of each layer, after leveling with motor grader,


should be 17.5cm. - Suitable water spraying is conducted up to Spraying water

the optimum water content state and compaction is done. - Compaction is done until obtaining the


density required in the Specifications.

Aggregate road base Material transportation:

Spreading:

1st compaction:

2nd compaction:

Dump truck

Motor grader

Vibratory roller

Tire roller

Subbase course material TAISEI CORPORATION

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c. Aggregate road base Aggregate road base is constructed as a base course to binder course for asphalt pavement, shown in flowchart below. Fig. 2.3.5.2 shows pavement structure, where base course is used.

Fig. 2.3.5.2 Pavement structure (aggregate road base)

Subbase course Material transportation

- Care is taken so that the material does not contain any harmful foreign materials. Also, transportation is done with care, so that integration of material does not occur.


- Suitable water spraying is conducted up to Spraying water

the optimum water content state and compaction is done. - Compaction is done until obtaining the


density required in the Specifications.

Prime coat for asphalt pavement Material transportation:

Spreading:

1st compaction:

2nd compaction:

Dump truck

Motor grader

Vibratory roller

Tire roller

Aggregate TAISEI CORPORATION

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d. Asphalt pavement Asphalt course is the final course of pavement constructed after the aggregate road base, as shown in the flowchart below. Asphalt pavement structure is shown in Fig. 2.3.5.3:

Fig. 2.3.5.3 Asphalt pavement structure

Aggregate road base Prime coat by distributor

- After completion of the aggregate road base, prime coat of asphalt emulsion is sprayed on it in order to enhance its adhesion to the asphalt course that comes on top. The sprayed quantity of asphalt emulsion will satisfy the requirement of the Specifications.

Asphalt binder course

- Laying of this course is done by an asphalt paver. The temperature of mixture shall be maintained within a range specified for each working stage. The first compaction is done by macadam roller and the second is done by tire roller in order to satisfy the compaction ratio required in the Specifications.

Tack coat by distributor

- Asphalt emulsion is spread to enhance adherence between the asphalt components. The sprayed quantity of asphalt emulsion will satisfy the requirement of the Specifications.

Asphalt wearing course

- Laying of this course is done by an asphalt paver. The temperature of mixture shall be maintained within a range specified for each working stage. The first compaction is carried out by macadam roller and the second is done by tire roller in order to satisfy the compaction ratio required in the Specifications.

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Traffic marking For laying of asphalt wearing course, one asphalt paver (adjustable paving width of 2.5-6.0m) is used. One macadam roller and one tire roller is provided for the paver for compaction. Asphalt paver

Macadam roller

Tire roller

Tandem roller (if necessary)

100−150m

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2.4 ENVIRONMENTAL PROTECTION IN THE OCH PROJECT a. Environmental Management Action Plan We will establish and submit to the Engineer the Environmental Management Action Plan within a month from the Date of Commencement with inventory of environmental impacts based on thorough study of environmental issues caused by construction activities, countermeasures for environmental protection, etc. Moreover, an Environmental Control Plan, ECP, is established for each execution to control environmental issues at a routine base. These plans are based on the following regulations: •

Central Environmental Agency, CEA, of the Ministry of Environmental and Natural Resources

•

Geological Survey and Mines Bureau, GSMB, in particular construction materials supply

•

Urban Development Authority, UDA, of the Ministry of Urban Development and Sacred Area Development, MUD and SAD

•

National Housing Development Authority, NHDA, of the Ministry of Housing and Common Amenities, NHCA

•

Guidelines: JBIC – Guidelines for Confirmation of Environmental and Social Considerations

Detailed environmental control schedules will be attached to these plans. Overall environmental protection work is carried out based on these plans and laws and regulations of the Democratic Socialist Republic of Sri Lanka. Occasional discussion and coordination meetings will be held with the Engineer and relevant authorities. The ECP will be routinely revised and altered based on these meetings. b. Environment control organizational structure Environmental management section, headed by an Environmental Manager, is established within the site organization to handle environmental issues. Major responsibility of the Environmental Manager is not only to carry out required works but also to discuss with the Project Manager, the Engineer, relevant authorities, Subcontractors, etc. for the sake of implementing environmental protection works. Moreover, he must always refer to the ECP and modify it as needed. Necessary number of staff will be assigned and report to him. c. Environment monitoring An environmental monitoring staff member is assigned in the environmental management section. He reports to the Environmental Manager. His duty is to carry out periodic environmental monitoring. Prior to the actual commencement of the Works, he monitors the existing environmental conditions. This monitoring is continued during the construction period so as to confirm the implementation of the ECP. The monitored result will be submitted to the Engineer. If any issue is reported, the Environmental Manager will promptly establish countermeasures to maintain good environmental condition. Major items to be monitored are as follows: TAISEI CORPORATION

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•

Air quality and dust

•

Water quality

•

Vibration and noise

•

Waste and soil contamination

•

Other impacts out of construction operations


d. Environmental education Environmental protection can be attainable only under the circumstance that all stakeholders of the Project understand the importance and theory of the environmental issues. Therefore, periodic lecture and training are provided not only to project staff but also to every worker. e. Environmental protection for each aspect Items to be investigated before actual construction activities are noise, vibration, air quality, water quality of rivers and wells, water table and conditions of existing housings, facilities, etc. of both public and private. These data shall be deemed to be the base. If a certain environmental concern arises, thorough explanation is given to local residents and necessary countermeasures will be provided before actual construction work. If needed, relocation of housings or facilities is executed. Details of each environmental aspect are as follows: •

Hydrological impacts: thorough discussion will be held among the Engineer, designer, and relevant authorities regarding hydrological impacts derived from the construction activities. Certain countermeasures are taken if required.

•

Water quality: necessary number of drainage ditches and pits are provided around the construction site. Water contaminated with oil or other deleterious matters are led to pits to be treated. No contaminated water is directly discharged to the river. Vehicles and equipment are washed only at the designated location so as no washing water directly goes into the river. If any negative effect is found in the water quality, investigation is carried out to find the cause and countermeasures will be taken if needed. During excavation of the soft ground and stock piling of it, appropriate measures such as protection earth dike or temporary cofferdam is provided so as to prevent the soil from being washed directly into the river. Similar device is also provided for other earthwork activities.

•

Air quality and dust prevention: routine maintenance is provided for all heavy equipments and other construction vehicles so as no excess exhausting gas is produced. Water sprinkling, covering sheet, temporary hoarding, etc. are provided for stockpiles to reduce dust volume caused by wind. Compaction of embankment and backfilling is carried out as soon as possible after spreading. Site is always kept clean and under neat condition with periodic water sprinkling. Specific filters are provided for cement silo or measuring hopper. If needed, dust prevention

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device such as cover, temporary hoarding, etc. will be provided for concrete plant, crushing plant, asphalt plant, etc. to prevent dust emission. All construction vehicles including dump trucks observe local traffic rules, especially the speed limit to reduce dust emission amount. Moreover, washing of tires is carried out before these vehicles go out of the site so as not to make public roads dirty. Unnecessary idling of engine is forbidden in order to reduce exhaust gas. Large dump trucks, 8-15tonne class, are employed as much as possible to reduce total vehicle number. •

Noise and vibration: work with heavy equipment is fundamentally executed during daytime and nighttime work is limited to such work with reduced noise or vibration. As for nighttime work, a meeting is held with the Engineer, local residents and us for mutual understanding of work contents, execution method, noise level, noise protection device, etc. Then, nighttime work that is approved by the Engineer is carried out. Heavy equipment and other construction vehicles are those of acoustic types as much as possible. Routine maintenance is executed and specific mufflers are set to equipment with engines so as to reduce noise level. Unnecessary idling is forbidden. Acoustic facility such as temporary hoarding with acoustic board is provided if needed for concrete plant, crushing plant, asphalt plant, etc. Piling work can be executed only under permission of the Engineer. All construction vehicles, including dump trucks keep local traffic rules, especially the speed limit to reduce noise level. Specific care is taken for execution of work with a big sound or severe vibration.

•

Construction waste and waste of accommodation: construction waste is discarded at the designated places. Re-usable waste is re-used as much as possible through discussion with the Engineer. Felling is limited only for those trees required from the point of view of execution. Waste control education is provided for all workers for the sake of effective separation of waste. Specified sewer treatment facility is provided at the accommodation.

•

Reduction of construction operation impact on land transportation: all construction vehicles use public roads strictly follow the local traffic rules and instruction of the Employer. Construction vehicles’ usage of public roads avoids traffic peak period as much as possible. Traffic signals, notice boards, barricades, traffic controllers, etc. are provided at intersections of construction roads and public roads for the sake of smooth traffic flow. Education and training of drivers are carried out, especially against taking alcohol or other narcotic drugs. Construction material is stocked at the stockpile as much as possible so that transportation of material can be reduced. Temporary construction road is constructed along the highway alignment, and transportation of various materials and equipment is forced to use this temporary construction road as much as possible to reduce traffic volume on public roads. Diversion roads are provided for those public roads across the ROW along with work progress for the sake of smooth traffic on public roads. Certain traffic safety device such as signals, notice boards, barricades, traffic controllers are also provided to these diversion roads. Periodic patrol for public roads used by

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construction vehicles is carried out. Once damage is found on the road, rectification work is immediately carried out.

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2.5 TRAFFIC MANAGEMENT AT NATIONAL ROADS A1, AB10 AND B214 In order to mitigate traffic congestion problems at National roads A1, AB10 and B214, the following countermeasures will be taken: a. Traffic operation plan will be established prior to major work commencement, taking into account current traffic conditions at each road, in order to control construction vehicles using public roads. b. Hauling routes to and from working areas will be established in order to avoid concentration of construction vehicles on certain routes, as long as actual site conditions permit. c. Traffic operation plan will be periodically monitored and revised based on changes in traffic conditions and progress of the Works in order to avoid traffic congestion as much as possible. d. Traffic notice boards, signals, warnings, barricades, etc. will be installed at intersections of the construction area and public roads. These traffic safety facilities will conform to the Manual on Traffic Control Devices published by the National Road Safety Secretariat, Ministry of Transport and Road Development Authority. Moreover, discussion with related authorities and the Engineer will be periodically held for the sake of ensuring smooth traffic. e. Traffic control personnel will be allocated at each intersection between existing national roads and entrance of the site in order to avoid traffic accidents and mitigate congestion. f.

The temporary bridge across Kelani River will be constructed as soon as possible after commencing the Works. This temporary bridge shall reduce traffic congestion due to construction vehicles on National roads AB10 and B214.

g. Kelani River bridge will be installed over National roads AB10 and B214. Installation plan to minimize traffic influence will be adopted according to Answer No.16 of Clarification No.04. h. Temporary yard will be provided near Kelani River, adjacent to the site, if possible. An access road connecting the temporary yard and the site will be constructed for smooth access, if necessary. i.

Concrete and asphalt plants will be set within temporary yard. Products from these plants are hauled to each execution site via construction roads within site premises.

j.

Material stockyard will be provided at temporary yard, thus aggregates and other raw materials can be hauled while avoiding heavy traffic periods.

k. Public roads shall not be made by our equipment and transport vehicles. Adequate washing facilities for the public roads, tires and equipment will be provided at appropriate locations. All precautions will be taken to avoid spillage of soil or any other material onto roads during transportation, and any such spillage will be removed to the satisfaction of the Engineer. l.

Damages to existing public roads, caused by construction vehicles used for the Works, will be repaired to the satisfaction of the Engineer.

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2.6 SOFT GROUND TREATMENT 2.6.1

GENERAL

Soft ground treatment (SGT) is divided into the following 8 (eight) types: SGT Type-A

Compacted general fill (50cm thick) + Gravel mat (50cm thick) + Surcharge

SGT Type-B

Compacted general fill (50cm thick) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

SGT Type-C

Compacted general fill (50cm thick) + Band drains + Gravel mat (50m thick) + Geotextile (1 layer) + Surcharge

SGT Type-D

Compacted general fill (50cm thick) + Gravel Compaction Pile (GCP) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

SGT Type-E

Compacted general fill (50cm thick) + GCP + Band drains + Gravel mat (50cm thick) + Surcharge

SGT Type-F

Compacted general fill (50cm thick) + GCP + Band drains + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

SGT Type-G

Compacted general fill (50cm thick) + GCP (Whole area) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

SGT Type-H

Replacement by excavation with compacted gravel Table 2.6.1.1 Grading requirement for gravel mat and GCP material Sieve size (mm)

Percentage by mass passing the sieve

50

100

37.5

85-100

20.0

50-80

5.0

15-40

2.0

5-25

0.063

0-5

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a. SGT Type-A Compacted general fill (50cm thick) + Gravel mat (50cm thick) + Surcharge

Fig. 2.6.1.1 Soft ground treatment Type-A Working area for SGT Type-A is kept dry during construction by using drainage ditches and pump pits. General fill is spread up to a thickness of 50cm by bulldozer and then compacted, with care not to disturb the original ground surface. Then, the gravel mat is spread uniformly by bulldozer up to a thickness of 50cm. After this, the gravel layer is thoroughly compacted. This is followed by embankment work carried out on the gravel mat. Gravel is crushed stone which is free from clay, lumps of dirt, organic matter or any other deleterious matters. Gravel will meet the grading requirements shown in Table 2.6.1.1. b. SGT Type-B Compacted general fill (50cm thick) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

Fig. 2.6.1.2 Soft ground treatment Type-B SGT Type-B uses geotextile sheet (tensile strength varies) in addition to SGT Type-A. General fill and gravel are spread and compacted in the same manner as for SGT Type-A. Geotextile sheet conforming to the requirements of the Specifications is installed on the gravel mat. In order not to damage the geotextile sheet, gravel surface is kept flat. Lapping length of at least 50cm is maintained at geotextile sheet joint portion. Embanking above the geotextile sheet is carried out immediately after geotextile sheet is installed in order to protect it from damage. TAISEI CORPORATION

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The sequence of works for SGT Type-A and SGT Type-B is indicated in Fig. 2.6.1.3: 1.

Preparation of construction road 4.0m

2.

Clearing & grubbing (20cm thick topsoil is removed) - Clearing by bulldozer, then loading & grubbing by backhoe

3.

Spreading & compaction of general fill (50cm thick) - General fill is spread & compacted, which then serves as a temporary road

4.

Spreading & compaction of gravel mat (50cm thick) & settlement monitoring plate installation - A first gravel mat (20cm) is spread & compacted, followed by - Settlement monitoring plate installation, then - A second gravel mat (30cm) is spread & compacted

5.

Installation of geotextile sheet (only for SGT Type-B) - Geotextile sheet (tensile strength varies) is installed on the gravel mat (only for SGT Type-B)

Fig. 2.6.1.3 Sequence of works for soft ground treatment Type-A and Type-B TAISEI CORPORATION

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c. SGT Type-C Compacted general fill (50cm thick) + Gravel mat (20cm thick) + Band drains + Gravel mat (30cm thick) + Geotextile (1 layer) + Surcharge

Fig. 2.6.1.4 Soft ground treatment Type-C SGT Type-C uses vertical band drains in addition to SGT Type-B sequence to accelerate settlement and improve the subsoil in areas of soft ground. A 50cm thick general fill layer is spread and compacted in the same manner as for SGT Type-B. Then, a first gravel mat is spread up to a thickness of 20cm. Band drain work is carried out on this gravel layer. Band drains are installed by penetrating into soft soil, maintaining designated intervals by using a backhoe mounted with a rig. Thorough ground investigation is carried out to determine the type and length of band drains. Band drain material will be conforming to the Specifications and be subject to the approval of the Engineer. Installation of band drains is executed until the drains reach the lowest part of the consolidation layer. Minimum overlapping length of band drains is 30cm. Specific care is taken in handling the band drain material. Care will be taken during transportation and storing of band drain material. The material will be protected from damage, rain or direct sunshine. Following band drain work, a second gravel mat of 30cm is spread and compacted so as the upper part of band drains is 30cm beneath the surface of gravel layer. One layer of geotextile sheet (tensile strength varies) is then installed on the gravel mat in the same manner as for SGT Type-B. Sequence of works for SGT Type-C is indicated in Fig. 2.6.1.5: 1.


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2.



3.


4.

Spreading of first gravel mat (20cm thick) - Gravel mat is spread up to a thickness of 20cm

5.

Band drain driving & settlement monitoring plate installation - Band drains are driven to the designated depth, followed by settlement monitoring plate installation

6.

Spreading & compaction of second gravel mat (30cm thick) - Gravel mat is spread & compacted up to a thickness of 30cm

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7.


Installation of geotextile sheet - Geotextile sheet (tensile strength varies) is installed on the gravel mat

Fig. 2.6.1.5 Sequence of works for soft ground treatment Type-C d. SGT Type-D Compacted general fill (50cm thick) + Gravel Compaction Pile (GCP, 700mm in diameter) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

Fig. 2.6.1.6 Soft ground treatment Type-D SGT Type-D uses Gravel Compaction Pile (GCP) in addition to SGT Type-B sequence. A 50cm thick general fill layer is spread and compacted in the same manner as for SGT Type-A thru C. Then, GCP work is carried out on this layer for the areas shown in Fig. 2.6.1.6. Gravel piles are installed by driving a casing pipe with a special device at its lower end to form a sand/gravel plug using pile-driving equipment. When it has penetrated to the required depth by vibration, the inside of the pipe is filled with gravel through the upper hopper on the pipe top. The TAISEI CORPORATION

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upper end of the pipe is then closed, and compressed air is applied inside the pipe while it is raised to certain height from the ground level. The gravel inside will be expelled from the pipe end simultaneously. Casing pipe shall be penetrated again with compaction of the gravel in the ground by further vibration. After the vibration has attained the required compaction degree and the required diameter of 700mm of the GCP, the casing will be raised to expel the remaining gravel from the casing pipe. The same penetration procedure accompanied by vibration for compaction work will be repeated until the whole gravel compaction pile is completed to the required ground level. Extra volume of gravel required for GCP is assumed to be 35% as this percentage is commonly employed, and the unit rate is based on this assumption. The actual extra volume shall be confirmed with the Engineer during test execution, and the actual unit rate shall be discussed between the Engineer and the Contractor to be fixed based on the test results. Then, gravel mat is spread uniformly by bulldozer up to a thickness of 50cm. After this, the gravel layer is thoroughly compacted. Gravel material both for GCP and the gravel mat will meet the grading requirements shown in Table 2.6.1.1. Sequence of works for SGT Type-D and SGT Type-G are indicated in Fig. 2.6.1.7: 1.


2.


3.


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4.


Gravel Compaction Pile (GCP) installation (700mm in diameter) - Casing pipe is driven to the designated depth by vibration, after which the pipe is filled with gravel - Gravel is then compacted and expelled out of the pipe end - The same penetration procedure accompanied by vibration for compaction work is repeated until the whole GCP is completed to the required ground level

5.

Spreading & compaction of gravel mat (50cm thick) & settlement monitoring plate installation - A first gravel mat (20cm) is spread & compacted, followed by - Settlement monitoring plate installation, then - A second gravel mat (30cm) is spread & compacted

6.

Installation of geotextile sheet - Geotextile sheet (tensile strength varies) is installed on the gravel mat

Fig. 2.6.1.7 Sequence of works for soft ground treatment Type-D and Type-G

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e. SGT Type-E Compacted general fill (50cm thick) + Area with GCP* + Area with band drains** + Surcharge * Gravel Compaction Pile (GCP, 700mm in diameter) + Gravel mat (50cm thick) **Gravel mat (20cm thick) + Band drains + Gravel mat (30cm thick)

Fig. 2.6.1.8 Soft ground treatment Type-E SGT Type-E uses GCP and vertical band drains in addition to SGT Type-A. A 50cm thick general fill layer is spread and compacted in the same manner as for SGT Type-A through D. Then, GCP work is carried out on this layer for the areas shown in Fig. 2.6.1.8. After this, the first gravel mat is spread up to a thickness of 20cm. Band drain work is carried out on this gravel layer in the same manner as for SGT Type-C, for the area shown in Fig. 2.6.1.8. Following band drain work, a second gravel mat of 30cm is spread and compacted so that the upper part of band drains is 30cm beneath the surface of gravel layer. f.

SGT Type-F

Compacted general fill (50cm thick) + Area with GCP* + Area with band drains** + Geotextile (1 layer) + Surcharge *Gravel Compaction Pile (GCP, 700mm in diameter) + Gravel mat (50cm thick) **Gravel mat (20cm thick) + Band drains + Gravel mat (30cm thick)

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Fig. 2.6.1.9 Soft ground treatment Type-F SGT Type-F uses geotextile sheet (tensile strength varies) in addition to SGT Type-E. A 50cm thick general fill layer is spread and compacted in the same manner as for SGT Type-A through E. Then, GCP work is carried out on this layer for the areas shown in Fig. 2.6.1.9 After this, the first gravel mat is spread up to a thickness of 20cm. Band drain work is carried out on this gravel layer in the same manner as for SGT Type-C and E, for the area shown in Fig. 2.6.1.9. Following band drain work, a second gravel mat of 30cm is spread and compacted so that the upper part of band drains is 30cm beneath the surface of gravel layer. One layer of geotextile sheet (tensile strength varies) is then installed on the gravel mat in the same manner as for SGT Type-B through D. Sequence of works for SGT Type-E and SGT Type-F are indicated in Fig. 2.6.1.10: 1.


2.


3.


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4.


Gravel Compaction Pile (GCP) installation (700mm in diameter) - Casing pipe is driven to the designated depth by vibration, after which the pipe is filled with gravel - Gravel is then compacted and expelled out of the pipe end - The same penetration procedure accompanied by vibration for compaction work is repeated until the whole GCP is completed to the required ground level

5.

Spreading of first gravel mat (20cm thick) - Gravel mat is spread up to a thickness of 20cm

6.

Band drain driving & settlement monitoring plate installation - Band drains are driven to the designated depth, followed by settlement monitoring plate installation

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7.


Spreading & compaction of second gravel mat (30cm thick) - Gravel mat is spread & compacted up to a thickness of 30cm

8.

Installation of geotextile sheet (only for SGT Type-F) - Geotextile sheet (tensile strength varies) is installed on the gravel mat (only for SGT Type-F)

Fig. 2.6.1.10 Sequence of works for soft ground treatment Type-E and Type-F g. SGT Type-G Compacted general fill (50cm thick) + Gravel Compaction Pile (GCP, 700mm in diameter, Whole area) + Gravel mat (50cm thick) + Geotextile (1 layer) + Surcharge

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Fig. 2.6.1.11 Soft ground treatment Type-G SGT Type-G incorporates the same sequence of works as SGT Type-D, however, in this case GCP is used for the whole area, as shown in Fig. 2.6.1.7 and Fig. 2.6.1.11. h. SGT Type-H Replacement by excavation with compacted gravel (case of peat and/or organic clay layer)

Fig. 2.6.1.12 Soft ground treatment Type-H SGT Type-H is totally different from SGT Type-A through G: soft ground is excavated and replaced with compacted gravel. Soft ground is excavated down to designated depth. Excavation is carried out by using backhoe; excavated material is hauled to dumping site by dump truck. Excavated soft ground is spread at the temporary stockyard to be dried under the sun, and then it is hauled to the designated dumping site. Excavation depth is deeper than 3m and water table is high in some areas. Replacement area is kept dry; therefore, drainage ditch and sump pits are provided as needed. Following the excavation, replacement material is spread. Rock material (of size 125-500mm) is spread by bulldozer and crushed stone (of size 0-40mm) is spread to fill all voids in the upper layer of the rockfill. They are TAISEI CORPORATION

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thoroughly compacted by vibratory roller. These replacement materials are hauled from quarries by dump trucks. Following the replacement work, gravel mat (50cm thick) is spread and embanking work starts. Sequence of SGT Type-H is indicated in Fig. 2.6.1.13: 1.


2.

Excavation of unsuitable material - Construction of temporary road at the soft ground portion to be replaced followed by - Excavation of unsuitable material

3.

Replacement with gravel - Gravel is installed from temporary roads, followed by - Spreading & compaction of gravel

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4.


Removal of temporary road, followed by spreading & compaction of gravel - Temporary road is removed within the soft ground portion to be replaced, followed by - Spreading & compaction of gravel

5.

Spreading & compaction of gravel mat (50cm thick) - Gravel mat is spread & compacted in 2 layers, up to a thickness of 50cm

Fig. 2.6.1.13 Sequence of work for soft ground treatment Type-H 2.6.2

PROPOSED DISPOSAL LOCATIONS

The proposed disposal locations (dumping sites) of the Project at this moment, i.e. D5, D9 and D12, are situated in the area shown in Fig. 2.7.2.1, chosen on the basis of thorough site investigation results. Excavated soil from each execution site is hauled to the proposed dumping sites D5, D9 and D12 by using National road B214. Total volume to be disposed is approximately 138,340cu.m. 2.6.3

SURCHARGE

Following embanking work, surcharge placement is carried out in order to facilitate ground stability. Surcharge is provided for SGT Type-A through G by banking an additional filling of 150cm or 220cm. TAISEI CORPORATION

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Surcharge material is fundamentally equal to the embanking material that is hauled by dump truck, spread and compacted by bulldozer. Essentially, for the purpose of making the Work Programme and costing of the tender, the earliest point of the time frame of the surcharge leaving period is employed and the surcharge leaving period is fixed to 6 calendar months. It is recognized, however, that monitoring of settlement shall be carried out throughout the surcharge period and the removal timing of surcharge material shall be determined by the result of monitored settlement and settlement predictions for 3 years. If the prediction that settlement in 3 years will not exceed 15cm is approved by the Engineer, the shaping of the subgrade and the placing of thhe subbase are executed. Surplus surcharge material is removed before subgrade shaping. If the predicted settlement in 3 years exceeds 15cm, an appropriate solution shall be discussed with the Engineer. Priority shall be given to solutions that maintain the leaving period assumptions stated in this document, such as providing additional surcharge to obtain adequate consolidation within the 6- month leaving period. We assume that the Engineer will fully cooperate in reasonably predicting the settlement which decides the leaving period of surcharge and preloading, especially for those areas that fall on the critical path (refer to Section 1.4 “Description of Critical Path Works” this document). Any increase of the assumed leaving period of such critical areas will lead to overall time delay on the Project delivery. If such increase is deemed unavoidable by the Engineer, the Contractor shall be entitled to extensions of time and additional payment of cost resulting from overall project schedule extension. 2.6.4

PRELOADING

In order to ensure foundation strength after forming the Gravel Compaction Piles (GCP) where box culverts and abutments of viaducts are located, consolidation of the existing ground takes place. Embanking and monitoring is carried out in the same manner as in the case of surcharge, described above. However, embankment height varies depending on location. After completion of consolidation according to the planned leaving period, surplus embankment is removed above the existing ground. The removed embankment material is used for embankment of highway main line. 2.6.5

MONITORING

Settlement and stability monitoring of ground starts following soft ground treatment works by placing monitoring plate with measuring bar onto the treated ground before placing any embankment material. Monitoring is applied for all soft ground treatment areas, SGT Type-A through H. Monitoring starts before embanking work and continues until the end of construction period. Monitoring plates are installed at about 50m intervals along the longitudinal alignment of the road.

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2.7 BORROW MATERIALS AND AGGREGATE QUARRIES 2.7.1

GENERAL

Earthworks materials shall be hauled by using public roads as quarries and borrow pits are located outside site premises. Major public roads to be used are National roads A1, B169, B262, B221, B214, AB10, and their access roads. Materials are hauled to site via these roads and delivered to execution areas. 2.7.2

PLANNING AND TRANSPORTATION

Rock material is derived from a quarry, QT (refer to Table 2.7.2.1); the total volume required is approximately 740,000cu.m. The hauling distance is approximately 20km. Hauled rock material is placed at execution areas, plant yard and temporary stockpiles. We confirm that no materials such as rock, stone or sand along the riverside is used as construction material in any way in view of environmental protection. The main borrow area, BT, planned at this moment is shown in Table 2.7.2.2. Assumed total required borrow volume is approximately 2,000,000cu.m. The hauling distance is approximately 40km. Borrow material is hauled to each execution area, the hauling route being via national roads, their access roads and newly developed access roads. 3 (three) dumping sites are planned outside the site premises (refer to Table 2.7.2.3). Total capacity of dumping sites is approximately 340,000sq.m, while the total volume to be disposed is approximately 210,000cu.m. Average hauling distance is approximately 12km. The hauling route is via site construction roads and National road B214. Hauling is carried out by using dump trucks, while hauled spoil is spread by using bulldozers. Earth banks and side ditches will be provided if needed to prevent mud from spreading out of dumping sites. Table 2.7.2.1 Details of quarry areas Location

Hauling distance (km)

Road route

Volume capacity (cu.m)

Q15

15

B214

1,200,000

Q16

18

B214

700,000

Q19

20

A1

400,000

QT

20

AB10-B214

Total

TAISEI CORPORATION

2,000,000 4,300,000

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Table 2.7.2.2 Details of borrow pits Hauling distance

Location

(km)

Road route

Volume capacity (cu.m)

BT

40

AB10, A4

B6

20

B214

300,000

B37

30

AB10

100,000

B38

30

AB10

200,000

Total

2,000,000

2,600,000

Table 2.7.2.3 Details of dumping sites Location

Hauling distance (km)

Road route

Area

Volume capacity

(sq.m)

(cu.m)

D5

12

B214

100,000

200,000

D9

12

B214

20,000

40,000

D12

12

B214

50,000

100,000

170,000

340,000

Total

Locations of quarries, borrow pits and dumping sites are indicated in Fig. 2.7.2.1. This drawing is based on Data Provided by the Employer (Northern Section-1), Part II: Geotechnical Data, 5. “Material Survey Details”.

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Fig. 2.7.2.1 Locations of supply and disposal plan

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2.8 CONSTRUCTION METHOD OF BRIDGES AND VIADUCTS 2.8.1

SUMMARY

The number of bridges in the Project is 22 (twenty-two). Bridgeworks consist of 5 (five) PC I-girder overpass bridges, 17 (seventeen) PC I-girder viaducts. Altogether, these bridges have a total length of approximately 6,500 m. Table 2.8.1.1 shows the summary and specifications for each bridge. Construction of bridges is the key work in this Project in order to keep to the specified schedule, and thus our serious consideration is required. We plan that partial approvals by the Engineer shall be given to the Contractor prior to the overall completion of the Detailed Design (D/D), toward specific items that need very long lead time in procurement. These items include piling machines, permanent casings of the piles, etc. Procurement of these items shall be commenced prior to the overall completion of the Detailed Design (D/D) following approvals by the Engineer. Bridge construction plan is based on the schedule specified in the Bidding documents and is as follows (refer to Section 1.1.3 “Additional points to be emphasized” of this document): •

Land acquisition (Commencement date of actual site works) Except Kelani River, we assume the schedule showing by Fig. 2.2.1 Overall project plan and Fig. 2.2.2 Work division into working sections.

•

Acquisition of Kelani River We assume that approval of all concerned authorities has been acquired for both temporary and permament Kelani River bridge construction.

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Table 2.8.1.1 List of bridges

No.

Bridge name

Crossing

Type of girder

D/D

K00 Kelani River Crossing Bridge (HB9)

16+140.000 Main road

PC I-girder×6×2

Required

383.00

11.65x2 (V/S)

[email protected][email protected]+20.0+40.0

71° In-situ Concrete Pile D1500

K01 Kelani River Crossing - Access Bridge 1 & 2

16+240.000

Side road

PC I-girder×4×2

Required

213.50

7.15x2 (V/S)

[email protected]+25.5


K02 Overpass Bridge No.08 (OB 08)

9+415.000

Crossing

PC I-girder×6

N/A

42.00

10.9

[email protected]



10+210.000

Crossing

PC I-girder×8

N/A

50.00

13.9

[email protected]

62° In-situ Concrete Pile D1500, Spread Foundation


11+261.000

Crossing

PC I-girder×8

N/A

44.00

13.9

[email protected]

77° Spread Foundation


12+518.921

Crossing

PC I-girder×13

N/A

45.00

22.1

[email protected]

71° Spread Foundation


14+843.000

Crossing

PC I-girder×6

N/A

45.00

10.9

[email protected]


A1 IC

Main road

322.00

11.75+16.00 (V/S)

[email protected][email protected]


K07 Viaduct No.1 (V1)

Sta.

PC I-girder×Vary Required

Length (m)

Width (m)

Span (m)

Skew

Foundation

Remarks

Curve

K08 Viaduct No.2 (V2) - 1st Biyagama Viaduct


PC I-girder×10

Required

1,505.00

22.1

[email protected]


Curve

K09 Viaduct No.3 (V3) - 2nd Biyagama Viaduct


PC I-girder×10

Required

420.00

22.1

[email protected]


Curve



PC I-girder×6×2

Required

280.00

11.65x2

[email protected]


Curve

K11 Viaduct No.5 (V5) - A1 IC Ramp-2 Bridge

A1 IC

Ramp

PC I-girder×4

Required

122.50

8.7 (V/S)

[email protected]

－ In-situ Concrete Pile D1500

Curve


A1 IC

Ramp

PC I-girder×4

Required

122.07

8.7 (V/S)


－ In-situ Concrete Pile D1500, Spread Foundation

Curve


A1 IC

Ramp

PC I-girder×4

Required

123.62

8.7 (V/S)



Curve


A1 IC

Ramp

PC I-girder×4

Required

137.57

8.7 (V/S)



Curve

K15 Viaduct No.9 (V9) - (Ramp 1)

15+860.000

Ramp

PC I-girder×4, 6

Required

178.50

7.9-12.3 (V/S)

([email protected][email protected])+(34.5+35.0)


Toll gate


15+860.000

Ramp

PC I-girder×4, 6

Required

232.50

7.9-12.3 (V/S)

[email protected]+([email protected]+24.0)+24.0+34.5


Toll gate

Main road

PC I-girder×6×2

Required

1027.00

11.65x2


Curve


16+523.000

([email protected])[email protected][email protected]+30.0+32. [email protected]


16+825.000

Ramp

PC I-girder×4, 6

Required

203.50

7.9-12.3 (V/S)

30.0+([email protected]+27.5)[email protected]


Toll gate


16+825.000

Ramp

PC I-girder×4, 6

Required

197.70

7.9-12.3 (V/S)

30.0+([email protected]+25.9)[email protected]


Toll gate


9+710.000

Main road

PC I-girder×6×2

Required

175.00

11.65x2

[email protected]

90° In-situ Concrete Pile D1500,

Curve



PC I-girder×6×2

Required

630.00

11.65x2

[email protected]


Curve

Total

6,499.50

where HB = Highway Bridge, OB = Overpass Bridge, IC = Interchange, N/A = Not applicable, V/S = Variable section

TAISEI CORPORATION

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2.8.2


WORKFLOW

Summary workflow of bridgeworks is shown below in Fig. 2.8.2.1:

Additional Soil Investigation

Preparation

Access Road & Working Platform

Piling

Detailed Design (D/D)

Partial approval for Procurement

Structural Excavation

Levelling Concrete

Pile Cap

Column

Bearing Shoes

PC Girder Fabrication

PC Girder Installation

Cross Beam

Deck Slab

Bridge Accessories

Off-site works

Paving

Fig. 2.8.2.1 Workflow of bridgeworks

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2.8.3


WORKING HOURS

In Sub-Clause 45.2 “Working Hours”, Part II: Conditions of Particular Application, Vol. II: Conditions of Contract, there are descriptions regarding working hours. However, we would like to propose the following working hours for the bridgeworks in order to avoid delay of the schedule: Piling works:

07:00 to 22:00

Fabrication works of I-girders:

24-hour operation

In Section 1.3.1.3 of this Method Statement we propose “Workable days”. Planned detailed workable days for each of the bridgeworks are as follows: Earthworks (40%): Structural excavation Piling works (75%): Piling, cofferdam, pile hacking and pile cap Other works (70%): Other than the works mentioned above Our schedule is made based on these working hours and workable days, moreover, in case other unforeseen reasons mentioned in this Section disturb our works, we will report the situation and require the Engineer’s approval for additional EOT. 2.8.4

PILING WORKS

Soil conditions of piling locations are mainly 3 (three) types, i.e. peat layer, soft clay layer and hard rock layer. Geological components are similar to those of the Southern Transport Development Project (STDP) Package 2, currently being executed by Taisei Corporation. However, piling equipment for bored piles is much larger than that for driven piles. For the execution of bored piles with a diameter of 1.5m, 150t crawler cranes are required to excavate hard rock layer. Suitable access road and working platform for heavy equipment shall be developed before starting of the piling works and after acquiring the ROW from the Employer. Piling works start after the development of the access road and working platform (refer to Section 1.2.4.2 “Preparing and maintaining firm and stable working formation” of this Method Statement). Rock hardness of the Project varies from qu=9.56N/sq.mm as the weakest to qu=67.38N/sq.mm as the strongest, assumed by the provided geological data in the Bidding Documents. The schedule of pile excavation speed assumed is based on a hardness of qu=50N/sq.mm. Furthermore, we consider that “sound bearing stratum” to fix pile tip elevation is defined by the value N, which is equal to N=50 (fifty). This idea is applied also for the Detailed Design (D/D) and the schedule.

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a. Permanent casing Casings may be left in position permanently especially in cases where: •

aggressive action of the ground water is to be avoided

•

piles are built in water

•

significant length of piles could be exposed due to scour.

Permanent casings will be installed inside temporary casings after excavation. The permanent casing specified in 502.3 “Bored Cast in Place Piles”, Section 502: Piling, Vol. III: Technical Specifications, shall be steel pipe casing with 11mm plate thickness and 1,500mm ID, to be installed down to the bearing stratum. Very long lead time is required in procurement of this material. Therefore, partial approval for the casing material shall be given by the Engineer prior to the final completion of detailed design for the sake of placing purchase order of the material. b. Piling method We plan to employ 3 (three) types of piling method: •

Reverse Circulation Method (RCD)

•

All Casing Method (AC)

•

Earth Drilling Method (ED)

1. Reverse Circulation Method (RCD) Excavation of soft layer is done by hammer grab or suction pump and excavation of hard layer is done by wing drill bit. To maintain stability of the borehole, the borehole wall is protected by temporary casing pipe driven down to the hard layer (refer to Fig. 2.8.4.1). Excavation of hard rock by this method is the firmest and fastest from the above methods. However, mobilization of this special machine needs long lead-time. 2. All Casing Method (AC) Excavation of soft layer is done by hammer grab with temporary casing and excavation of hard layer is done by drop chisel and hammer grab with temporary casing. In order to maintain the stability of the borehole, the borehole wall is protected by temporary casing pipe driven down to the toe of the pile (refer to Fig. 2.8.4.2). Excavation of hard rock by this method is firm, but less speedy than that of RCD. However, mobilization time of this machine is much shorter than that of RCD. 3. Earth Drilling Method (ED) This method is commonly used in Sri Lanka. Excavation of soft layer is done by drilling bucket and excavation of hard layer is done by drilling bucket with rock bit. To maintain the stability of the borehole, the borehole wall is protected by drilling fluid with standpipe. However, the speed of excavation of hard rock is slow and the capability of this machine is doubtful when encountering very hard rock, i.e. “qu” is over 150N/sq.mm. TAISEI CORPORATION

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Our schedule is made under the following conditions: •

Approvals for diameter of piles and type of piles are given by the Engineer, even before the approval of final Detailed Design (D/D)

•

Approvals for method of piling and for Subcontractor, if applied, are given by the Engineer, even before the approval of final Detailed Design (D/D)

•

Specimens of test piles (static and dynamic) are permanent piles that extend to the ground level, because these tests are for proof testing

•

According to the item No.15, Clarification No.02, the pile load testing shall be carried out using permanent piles. Thus, this testing is not a decisive but a capacity proofing one. We planned the time frame of our piling work as indicated in the Work Programme, recognizing that permanent piling work shall be executed continuously without being interrupted even during the testing periods.

•

Piling work shall be carried out continuously from drilling up until concrete placement without interruption as specified in 502.3 “Bored Cast in Place Piles”, Section 502: Piling, Vol. III: Technical Specifications. Considering the ground condition, the work cannot be completed within normal working hours, but always needs overtime work. Therefore, working time of piling is considered to be from 07:00 to 22:00. The Contractor shall not be responsible for overtime fees for the Engineer’s representative, staff, etc., derived from these prolonged working hours.

•

In regard to Bearing Stratum mentioned in 502.1 “Description”, Section 502: Piling, Vol. III: Technical Specifications, the N value of 50 is considered as the requirement that the stratum be recognized as Bearing Stratum. Actual determination that bearing stratum has been encountered is done by using alternative evaluation factors such as drilling speed, etc. approved by the Engineer.

TAISEI CORPORATION

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Fig. 2.8.4.1 Reverse circulation method (RCD) TAISEI CORPORATION

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Fig. 2.8.4.2 All casing method (AC) TAISEI CORPORATION

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2.8.5


SUBSTRUCTURE

Following the piling work, substructure work starts. Excavation work for structures is in accordance with the Specifications. Excavated soil is temporarily stocked nearby the excavated location and is used for backfilling. Temporary stockpile shall be placed so as not to obstruct drainage of the site or surrounding area. Unsuitable materials for backfilling are transported to disposal location approved by the Engineer. Cofferdam may be needed to protect cutting slope depending on soil and weather conditions. Submergible pumps may be necessary for discharging the water from excavated area. After excavation, gravel mat and lean concrete will be put as a base of pile cap in accordance with the Drawings. We consider that the bearing capacity of lean concrete and gravel mat against the load of fresh concrete of pile cap is strong enough and therefore we do not consider any reinforcement for gravel mat or lean concrete in our plan. Then, pile cap works and column works will be done. The accuracy of forming, the lapped length and size of rebar, etc. shall be thoroughly checked based on the Specifications and Drawings. Any deficiency shall be rectified to be within the tolerance of the specified values. Concrete pouring is carried out by using concrete pump or hopper. Concrete compaction is carried out firmly by using vibrators. Curing of poured concrete shall be carried out with water and/or curing compound and suitable sheets. Concrete construction joints shall be treated in accordance with the Specifications by using jet washer and/or wire brushes. For column works, safe working platform shall be prepared for works in high places. Steel support for overhanging column head is used with jacks (refer to Fig. 2.8.5.1). During or after execution of column work, backfilling work for structural excavation area will be done by using qualified excavated soil. Backfilling method and its quality control shall comply with the Specifications and the Drawings.

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Fig. 2.8.5.1 Steel support system for overhanging column head of viaduct TAISEI CORPORATION

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2.8.6 2.8.6.1


SUPERSTRUCTURE PC I-GIRDER BRIDGES

The girders of this type of bridge are pre-stressed concrete (PC) I-shaped girders. PC I-girder bridges of the Project have various girders per span, respectively (refer to Table 2.8.1.1 for details). Maximum weight of a viaduct girder is approximately 81 tones with 40.0m long. Girders are fabricated and stored at the fabrication yard, then transported by trailers to the site for installation works. We plan 2 (two) locations as girder fabrication yard and also 2(two) locations as temporary stock yard inside or near ROW of the Project respectively. This information is only for planning since we are not sure at this moment whether we can acquire the yard area as per our request. Ground bearing capacity on the site is not strong enough and existing ground elevation is too low considering flooding in the rainy season, therefore all works shall be carried out on an elevated platform on the embankment to secure installation works. a. Girder fabrication Girder fabrication will be done at the fabrication yard as mentioned above (refer to Fig. 2.8.6.1.1). Special fabrication yard will be made taking very tight schedule of fabrication into account, including rebar cage fabrication yard, formwork system and cranes for transporting fabricated girders. Special facilities for rapid and massive execution system for PC-I girder fabrication are: •

24 casting beds (8 girders per day) (refer to Fig. 2.8.6.1.2)

•

Rebar prefabrication method

(refer to Fig. 2.8.6.1.3 and Fig. 2.8.6.1.4)

•

Systematic formwork system

(refer to Fig. 2.8.6.1.5)

•

Large span gantry cranes

•

Yard-A; Stockyard for fabricated girders in fabrication yard (max. stock number of girders is approx. 115)

•

Yard-B; Stockyard outside of fabrication yard (max. stock number of girders is approx. 65)

Each 2 nos of Yard-A and Yard-B are planned. As a result, the maximum number of temporary stock girders is to be around 360 nos compare with total 1,957 nos. Please refer to Fig. 2.8.6.1.6, regarding the sequence of PC I-girder fabrication. Cycle time of girder fabrication is planned to be 4 (four) days. Daily production number of girders is 8 (eight). Rebar cages will be pre-fabricated in rebar yard to reduce time of casting bed usage, and cages will be transported to the casting beds by gantry crane using special hanging jig. PC stressing will be done after confirmation of proper strength of concrete (specimen is cube).

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Fig. 2.8.6.1.1 General arrangement of temporary facility)

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Fig. 2.8.6.1.2 Precast yard outline

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Fig. 2.8.6.1.3 Rebar jig detail TAISEI CORPORATION

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Fig. 2.8.6.1.4 Rebar cage lifting frame TAISEI CORPORATION

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Fig. 2.8.6.1.5 Typical section of formwork system TAISEI CORPORATION

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Fig. 2.8.6.1.6 Sequence of PC I-girder fabrication TAISEI CORPORATION

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After PC stressing, fabricated girders will be transported to the stockyard by gantry crane and stocked at least 28 days, considering deformation of the girders by creep. Rebar work, formwork and concrete work will be done in 24-hour working shift. b-1. Girder installation by Tandem Crane Erection Direct setting method is applied as PC I-girder bridges construction method. I-girders are fabricated at temporary yards in order to be transported to site and installed by two cranes directly to the specified final position. This method can be applied for those areas that can allow cranes to be set between piers and abutments (refer to Fig. 2.8.6.1.7 and Fig. 2.8.6.1.8).

Fig. 2.8.6.1.7 Workflow for PC I-girder bridges

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Fig. 2.8.6.1.8 Direct setting method TAISEI CORPORATION

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b-2. Girder installation by Travelling Erection Girder (TEG) Erection Girders are installed by Travelling Erection Girder at locations where it is not possible to apply tandem crane erection, especially Kelani River crossing area. This method is planned to be applied from P11 to P14 of HB 9 and Access Bridge. Please refer Fig. 2.8.6.1.9 to Fig. 2.8.6.1.14.

Fig. 2.8.6.1.9 Election Sequence by TEG (1)

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Fig. 2.8.6.1.11 Election Sequence by TEG (3) TAISEI CORPORATION

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Fig. 2.8.6.1.13 Election Sequence by TEG (5) TAISEI CORPORATION

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c. Cross beam and slab works After installation of girders, the cross beam works and slab works start. Each bridge span has 3 (three) to 4 (four) cross beams. Cross beams within a span are proceeded in parallel. Hanging platform and support are required for cross beam work (refer to Fig. 2.8.6.1.15 ). Steel beams on the top of installed girders support this platform and support. Platform is installed on both sides of cross beam for rebar work, PC work, and formwork. After casting concrete, PC tensioning work is executed for transverse PC tendons. Temporary supports to maintain the location of installed girders are not to be dismantled until finishing transverse PC tensioning works. A proper access way to reach the working platform shall be kept open during this work. Afterwards slab works start. Instead of bottom formwork support between girders, pre-cast concrete plates are installed as formwork, conforming to the Drawings. However, conventional support is necessary for the outside of the edge girders. Concrete will be cast from the middle of each span at first, considering the deformation of the bridge, and concrete on piers will be cast subsequently in order to avoid improper stress to the bridge superstructure.

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Fig. 2.8.6.1.15 Support system for cross beam works

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2.9 CONSTRUCTION METHOD OF KELANI RIVER BRIDGES (STA.16+300) Kelani River bridges, i.e. Main Bridge (HB9) and Access Bridge 1 & 2, all at Kaduwela Interchange, are planned across Kelani River. Three piers are allocated in the said river. Temporary bridge and working platform will be installed for approaching and constructing these piers. Double sheet pile cofferdam system will be adopted to construct these structures in dry condition (see Fig. 2.9.2 and Fig. 2.9.3).

Construction of temporary bridge and platform

Installation of double sheet pile cofferdam system

Construction of substructure (pile, footing, pier column)

Removal of double sheet pile cofferdam system

Installation of temporary pile for bent to install steel girder

Installation of steel girder

Removal of temporary bridge and platform Fig. 2.9.1 Workflow for Kelani River bridges As indicated in answer No.35 of Clarification No.02, all approvals to construct these temporary and permanent structures are already given to the Employer by the Irrigation Department. For the method statement, further approval of the Engineer will be required.

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Fig. 2.9.2 Construction of temporary bridge and platform

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Fig. 2.9.3 General section of double sheet pile cofferdam

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2.10 THERMAL CONTROL FOR STRUCTURAL MASS CONCRETE In the Addendum dated 21st February 2011, it is provided that the Contractor shall perform the thermal control for the structural mass concrete in accordance with Item 503 of Specification. While the definition of “the structural mass concrete” has been given in the Specification, the method to control the temperature of the structural concrete (“the Thermal Control Method”) is up to the Contractor. From our experience, we believe that it is important for the Thermal Control Method to take into account a mock-up test at the site as well as theoretical study. Thus, we would like to leave open the details of the Thermal Control Method thus far. Then, after the Contract is awarded to us, we would discuss with the Engineer what method is appropriate and practicable for the Thermal Control Method, also taking into account our experience with the STDP.

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3. PART 3: CONTRACTOR’S QUALITY MANAGEMENT PLAN

3.1 SCOPE AND PURPOSE OF PROJECT QUALITY MANAGEMENT PLAN This Project Quality Management Plan (hereinafter called QMP) applies to “Outer Circular Highway (OCH) to The City of Colombo Project – Northern Section-1” in Sri Lanka. The purpose of QMP is to set out the specific work practices, methods, procedures, allocation of resources, and schedules, etc. for different phases of the Works in accordance with the Contract documents. QMP integrates all these requirements and is carried out, implemented and maintained during the execution of the Project to the satisfaction of the Engineer and the Employer. The Quality Assurance Plan (QAP) described in Schedule IX assigns responsibilities and authorities to ensure a correct and auditable implementation of the QMP.

3.2 QUALITY OBJECTIVES OF THE PROJECT Taisei Corporation is committed to execute each project to the satisfaction of the Employer and with due thought for all stakeholders. The main project quality objective is: “Eliminate nonconforming products, while maintaining the highest standard of safety and due consideration to the environment”. In order to achieve the project quality objective each division has its individual quality goal: •

Construction Division “Eliminate re-work by ensuring FIRST TIME PASS on inspections”.

•

Project Controls Division “Save time by ensuring FIRST TIME PASS on submissions and achieving a turn-around time of not greater than14 days”.

•

Administration Division: “Maintain the Employer’s satisfaction by preventing complaints”.

•

Health, Safety and Environment Division: “Maintain a safe work environment to prevent lost time accidents”.

•

Quality Assurance Division: “Ensure first time quality: no nonconforming completed products”.

•

Engineering/Design Division: “Make rational designs that comply with client demands, and manage a design schedule so as not to hinder construction work”.

Division managers will measure their division’s success in meeting their quality goal. Monthly, the Project Manager will hold a quality meeting with division managers to review each division’s success in meeting their quality goal.

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3.3 PROJECT QUALITY MANAGEMENT SYSTEM Our quality management system for all phases of the Works is based upon ISO 9001:2000, issued by the International Organization for Standardization. The quality management system includes procedures/plans for the issues listed below: •

Integration of different engineering systems in each discipline/division to achieve a uniform tracking, control and reporting system

•

System of preparation, checking and approval of engineering, procurement of construction documents

•

System of dealing with design/document changes and revisions

•

Selection and control of vendors and Subcontractors with respect to the acceptance and monitoring of their operative quality system

•

System and resources for satisfying the technical, quality and safety requirements of applicable regulations, control of interfacing activities and lines of communications between the various activity centers and work site and/or between the various disciplines/working parties, including the proposed coordination procedures

•

Nonconformance control system

•

Plan of anticipated internal and external quality audits

•

Plan of inspection activities for all phases of execution of the Works, including assignment of staff and proposed independent inspection agencies

•

Engineering quality control procedures covering all events with regard to engineering and design activities for the Works

•

Construction quality control procedures for the Works covering field inspection and testing civil works, electrical works, system testing, pre-commissioning and commissioning, etc.

3.3.1

ENGINEERING/DESIGN QUALITY MANAGEMENT & CONTROL

Taisei Corporation addresses all aspects of design control in the quality control procedures for engineering work with the aim to guarantee adherence to the design policy/objectives, statutory, performance and technical requirements of the Works as specified in the Specifications. The procedure covers the following issues: -

Review and confirmation of Technical Data Sheets (TDS)

-

Design input

-

Interface control/Inter-discipline review

-

Applicable design codes/Standard drawings/Design methods, incl. software

-

Interface with Subcontractors

-

Inspection of materials

-

Engineering verification and design outputs (deliverables)

-

Review and approval of the Employer

-

Change control

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3.3.2


PROCUREMENT QUALITY MANAGEMENT & CONTROL

Taisei Corporation ensures that all project materials and equipment procured confirm to the Project Specifications. Materials, suppliers/vendors are evaluated and approved by the Engineer and the Employer prior to the issuance of Purchase Order by Taisei Corporation. The procurement quality management system identifies the following issues: •

Material submittal/Vendor submittal

•

Purchase order requirements (incl. Project Specifications/Statutory/Shipping, etc.)

•

Inspection and test plans

•

Third party inspection agency (TPIA) level of inspection and verification at vendor premises

•

Pre-inspection meetings (where applicable/appropriate)

•

Control of vendor procedures

•

Control of nonconformities

•

Vendor inspection coordination, production status follow-up, etc.

•

Inspection reports/Test certificates

•

Final inspection (prior to release for shipment) and Factory release certificates

•

Vendor documentation (Factory reports/Trial system functional reports/Vendor data book/ As-built drawings, etc.)

3.3.3

CONSTRUCTION QUALITY MANAGEMENT & CONTROL

Taisei Corporation will establish quality control procedures solely dedicated to construction activities. The Inspection and Test Plan for the construction works are formulated to address each work phase. The Inspection and Test plan identify activities pertaining to pre-assembled fabrication, construction, systems testing and commissioning, and are issued to the Engineer and the Employer for approval as a part of the overall Quality Plan. Taisei Corporation carries out all necessary inspection and testing during the execution of the Works in order to ensure that work is executed in accordance with the Project Specifications requirements. We will assign competent persons for the quality control tasks who will be familiar with the applicable codes, statutory requirements and Project Specifications requirements. Taisei Corporation will ensure that work site quality control plans/procedures are formulated for all Subcontractors to identify the specific quality practices needed to administer their activities. We will address interfaces in the Works with Subcontractors and issued to the Engineer and the Employer as part of the project quality management system.

The construction quality management system identifies the following activities (but it is not limited to TAISEI CORPORATION

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only these items): •

Field inspection of civil works

•

Field inspection of site investigations and topographical survey

•

Field inspection of geotechnical investigations

•

Field inspection of concrete

•

Field inspection of roads, paving, surfacing, etc.

•

Field inspection of structural steel

•

Field inspection of electrical equipment

The detailed field tests that will ensure achieving the above objectives of the construction quality management plan are described in the following paragraph.

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3.4 INSPECTIONS AND TESTS PLAN The list on this page and the following pages is the plan for the inspections and the tests that will assure quality of all activities during the Project: Section no./Type of construction

Material acceptance test

Work routine test

Frequency

Earthworks General fill - Embankment fill up to subgrade level - Backfilling after excavation of unsuitable material

Grading

Twice a week or 1,000cu.m, whichever is greater

Atterberg limits

1 per 1,000cu.m

CBR

1 per 1,000cu.m

Max. dry density/ Optimum moisture content

Selected material (Granular or cohesive) - Capping on embankments

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1 per 500cu.m or twice per section

Degree of compaction of compacted layer

1 per 500cu.m or twice per section

Grading

1 per 300cu.m or each source, whichever is greater

Atterberg limits


CBR



Top of subgrade

Moisture content prior to compaction


Moisture content prior to compaction

Regularly


1 per 300cu.m


1 per 300cu.m

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Section no./Type of construction Selected uniformly graded granular material - Rockfill - Porous backfill to structures - Permeable backing layer to structures - Drainage layer - *Fill to reinforced earth



Work routine test

Grading


Frequency 1 per 200cu.m or as required


Plasticity index *Chloride iron content *Total sulphate content

1 per 300cu.m or as required

1 per source 1 per source 1 per source Moisture content

Regularly



Gravel for GCP/ Gravel mat

Grading


Geotextile

Ultimate tensile strength Permeability Pore size

As directed by the Engineer Manufacturer’s test results/Every batch

Grading

1 per 300cu.m

Atterberg limits

1 per 300cu.m

Percentage of wear LAAV Aggregate impact value

1 per 300cu.m

Flakiness index

As required

Soundness

1 per source

CBR (4 days soaked)

1 per 300cu.m

Subbase and base courses Subbase - Type I - Type II - Type III

Aggregate road base


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1 per 300cu.m

Moisture content

Regularly


1 per 300cu.m

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Section no./Type of construction Asphaltic material - Asphalt cement



Work routine test

Penetration

1 per 750 tonnes

Softening point

1 per 750 tonnes

Other acceptance tests as per BS 3690-1:1997

Every batch

Rate of application - Cutback asphalt

- Emulsified asphalt

Shoulders

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Frequency

Acceptance tests as per Section 1302.2

2 per day Every batch

Rate of application

2 per day

Temperature of application

Regularly

Acceptance tests as per Section 1302.3

Every batch

Rate of application

2 per day


Regularly

Grading Atterberg limits

1 per each soil type thereafter 1 per 300cu.m

CBR (4 days soaked)

1 per each soil type thereafter 1 per 300cu.m


1 per each soil type Moisture content

Regularly


1 per 300cu.m

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Section no./Type of construction Pavement Asphalt bound base/ Asphalt concrete



Work routine test

Frequency

Acceptance tests for binder

1 per day or as required

Aggregate grading

1 per each source or 400cu.m, whichever is greater

Aggregate impact value 1 per each source or 400cu.m, whichever is greater

Flakiness index Los Angeles abrasion value (LAAV) Coating and stripping test Acceptance tests of filler

As required Temperature of binder Temperature of aggregate Temperature of mixing Temperature of laying

At regular close intervals

Hot bin grading Compliance to job mix Bitumen extraction and compliance to the job mix Marshall stability and flow Density and void tests of Marshall specimens

1 test per day or 300 tonnes, whichever is greater

Thickness of compacted layer 1 test per 250cu.m Degree of compaction of compacted layer TAISEI CORPORATION

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Section no./Type of construction Asphaltic prime coat & tack coat

Seal coat surface treatment



Work routine test


Frequency As required

Depot tray test

At least once a month

Rate of application

2 tests per day


Regularly


As required

Aggregate impact value Flakiness index Los Angeles abrasion value

1 test per source or 200cu.m, whichever is greater

Coating and stripping test Soundness of aggregate, clay, salt, dust, fraction of aggregate & water absorption Grading of aggregate

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Depot tray test

At least once a month

Rate of application of binder

1 per 500sq.m

Temperature of application of binder

Regularly

Rate of spread of aggregate

1 per 500sq.m

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Section no./Type of construction Structures



Work routine test

Frequency

Acceptance tests for cement

Manufacturer’s certificates

Acceptance test for water

1 per source

Acceptance tests for admixture


Acceptance tests for aggregate - Flakiness index - 10% fines value - Chloride content - Alkali-silica reaction

1 per source and as required

Concrete

Grading

Grouting

Reinforcement for structures

Acceptance test for reinforcements as per BS 4482, BS 4483 & BS 4489

Piling

Bored pile

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Moisture content of mixing aggregate

Daily

Temperature of fresh concrete

Regularly

Casting of test cubes for compressive strength and flexural strength

1 per 100cu.m

Cube strength

As directed by the Engineer Manufacturer’s certificates and 1 per each batch as required

Sonic logging test for pile integrity

All bored piles

High strain dynamic pile test

1 pile per pile group for every bridge

Static load test for pile

1 pile selected by the Engineer

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Section no./Type of construction Prestressed concrete

Steel structure


Work routine test

Frequency

Acceptance test for prestressing tendons


Acceptance test for anchorage assemblies


Acceptance tests for steel

Manufacturer’s certificates (Mill certificates, test results)

Acceptance tests for bolts, nuts and washers

Manufacturer’s certificates (Capacity tests, samples)

Welding works

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Quality of welds

Daily

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4. Method Statement 20110321

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