Method of Statement for in Situ Box Culvert

PENSWASTAAN PENYELENGGARAAN JALAN – JALAN PERSEKUTUAN DI SEMENANJUNG MALAYSIA (ZON SELATAN)

METHOD OF STATEMENT FOR INSTALLATION OF BOX CULVERT 1.0

OBJECTIVE 1.1This method statement is to describe the outline construction methods for the installation of in-situ Box Culvert structure across the road.

2.0

3.0

LIST OF EQUIPMENT AND MECHINERIES 2.1

The following equipment and machineries shall be used,



Hydraulic Excavator



Mobile Crane



Pile Rig



Ready - made concrete/ concrete mixer



Welding Set



Compactor Roller



Backhoe



Portable Water Pump



Haulage tippers for disposal of spoils



Small tools



Site Engineer



Site Supervisor



Survey team & equipment

CONSTRUCTION METHODS 3.1

Introduction 3.1.1 This method statement applies to all personnel involved in the construction

and

supervision

of

the

works

including

the

Consultant’s site staff required for inspection and approval of the works.

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3.1.2

Material for permanent construction such as concrete mix, reinforcement etc shall be submitted by the Site Engineer in the form of samples, technical brochures and all approvals in writing

to

be

obtained

from

the

consultant

prior

to

commencement of the works. 3.1.3 The invert level of the box culvert at inlet and outlet points shall be determined using survey equipment and marked at site on timber peg for easy reference. 3.1.4 The Survey Team shall ensure that all setting out works are in order. Survey field data for later reproduction of as-built drawings shall be kept and documented by the supervisor. 3.1.5 Backfilling materials to be used as bedding or backfilling (crusher run, sand) shall be stockpiled at strategic area before laying works commencing.

3.2

Traffic Management 3.2.1 The installation of traffic safety devices shall follow the approved Traffic Management Plan. The devices and signboards must comply with the specifications. 3.2.2 Prior to commencement of physical works, traffic management and all lane closure programs shall be checked and approved by respective

Traffic

Safety

Officer

before

the

construction

activities can commence. 3.2.3 The traffic team member must wear suitable clothing to ensure they can be seen clearly by the road users. 3.2.4 Flagman to be stationed at both ends of the road closure to guide the road users and to control the flow of traffic.

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3.3

Cutting of Road Surface 3.3.1 The first step is to demarcate the excavation area. Lines are drawn on the road surface to mark the width of the trench. 3.3.2 Normally the trench width will be slightly wider (i.e 600mm on each side) than the width of the Box-culvert to be installed works. This will be the working space during laying of BoxCulvert and also for manual compaction of backfilling material. 3.3.3 A breaker will be used to cut the top surface of the road along the marked lines to ensure the cut section will be neat in appearance and with less damage to the adjacent road during the excavation work.

3.4

Excavation 3.4.1 Prior to the excavation works, the area shall probably marked as a guide to control the longitudinal alignment of the culvert crossing. 3.4.2 Excavator shall be used for the excavation works as it can expedite the work progress. 3.4.3 The excavation work must be followed immediately with the bedding preparation and also laying of the Box-culvert. This is to avoid excavation wall from collapsing and to control the water level inside the trench. The length of the excavated trench shall not be more than 10m. 3.4.4 The supervisor must monitor the excavation work and check the level from time to time to avoid over excavation and to ensure the correct gradient for the laying work is achieved.

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3.4.5 Water pump of suitable capacity shall be operating to keep the excavated trench essentially dried. 3.4.6 The excavated soil shall be stockpiled nearby and shall be used as backfilling material if found suitable. Unsuitable soil shall be removed from site a soon as possible.

3.5

Piling Works 3.5.1 Pile need to be supplied by approved pile manufacturer with SIRIM endorsement with minimum structural capacities and concrete grade as specified. 3.5.2 Care shall be taken to ensure piles are not damaged or broken during transportation lifting and handling. 3.5.3 The stock area/ yard shall have sufficient space for handling, lifting, maneuver of lifting cranes and transportation vehicle. 3.5.4 Before allowing the pile rigs to enter site, ensure there are no overhead cables or obstructions which could be damaged by ring movements. 3.5.5 Ensure that the site has been suitably prepared and its level, and that any services have been clearly identified, protected and diverted as necessary by the main contractor. 3.5.6 The pile position shall be set out using pins/ pegs. 3.5.7 Two reference steel pins or pegs shall be located equidistant from the pile center location pin. 3.5.8 The RC pile would then be pitched and positioned into the exact pile position such that the reference pins/ pegs are equidistant from the pile face. 3.5.9 Vertical plumb lines to sight the sides of the pile from two different directions would be used to check and control the verticality of the piles during driving.

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3.5.10 A carpenter spirit level shall be used regularly during the course of the piling as an additional measurement to monitor the verticality of the pile. 3.5.11 A thick hardwood cushion shall be placed at the pile head during the driving and shall be replaced at regular intervals. 3.5.12 Connection of pile segments shall be done by means of continuous all round butt weld along the circumferential grove of mild steel plate of the pile as recommended by supplier. 3.5.13 A full time recorder man shall be attached to the pile-driving rig to record the blows during the driving process. 3.5.14 The final set of each pile shall be recorded either as the penetration in mm per 10 blows or as the number of blows required by set calculation (Hiley’s Formula).This shall be submitted prior to the commencement of piling works. 3.5.15 Set of driven piles, The set for particular site and working load cannot be established until preliminary piles have been driven and the driving records checked against the ground conditions assumed in design. The set may have to be modified as a result of loading test. 3.5.16 Tolerance in plan position, the maximum permitted deviation of the pile center from the center points shown on the Drawings shall not exceed 75mm in any direction. 3.5.17 The maximum permitted deviation of the finished pile from the vertical is in 1 in 75 3.5.18 When a pile has been driven to the required set, the head of the pile shall be cut off using the air breaker. 3.5.19 The cut shall be to the level specified or indicated in the engineer’s drawing.

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3.6 Preparation for Foundation 3.6.1 The foundation shall be prepared as shown in the drawings and a joint inspection with the consultant site staff shall carried out and recorded in the Request for Inspection form. 3.6.2 Dewatering by water pumps may be required to enable a dry surface for working. 3.6.3 When the excavation level is reached, the soil shall be leveled and compacted to ensure strong support layer. 3.6.4 Crusher run (hardcore) shall be placed, leveled and compacted as bedding to support the box culvert. 3.6.5 The supervisor must check the thickness of compacted hardcore layer and also the gradient to ensure when the culvert was installed, water will flow in the intended direction. 3.6.6 Where

blinding

immediately

layer

after

the

is

required,

foundation

it

should

preparation

be has

placed been

completed to protect it from inclement weather. 3.7 A

In-Situ Box Culvert Construction Slab 3.7.1 The area of the proposed slab shall be set out with timber shuttering supported in place to cast the concrete slab. 3.7.2 A minimum 30/20 concrete mix shall be used. This will ensure a concrete of 30N/mm2 and the biggest aggregate size of 20mm. 3.7.3 The required reinforcement bars shall high tensile bars be placed in position, ensuring the required cover and the slab length is maintained. 3.7.4 Place and compact the concrete to the finishing depth, making sure the concrete is under the channels. 3.7.5 The slab shall be compacted using a vibrating screed and poker vibrator, to ensure the removal air trapped during the mixing process.

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B

Wall 3.7.6

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Method of Statement for in Situ Box Culvert

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