GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
CADANGAN MENAIKTARAF LOJI RAWATAN KUMBAHAN BANDAR MAHKOTA CHERAS (HLT 227), SELANGOR
METHOD STATEMENT
CONTRACTOR :
MEWAH KOTA SDN BHD NO. 2 JALAN APOLLO U5/190 BANDAR PINGGIRAN SUBANG SEKSYEN U15 40150 SHAH ALAM SELANGOR
CONSULTANT : UNITI CONSULTANTS SDN BHD 25. Jalan Bunga Raya 8, Senawang Business Centre, Taman Tasik Jaya, 70450 Seremban, NSDK. Tel: +606 - 678 0203 / Fax: +606-679 2308
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
PROPOSED METHOD STATEMENT FOR SEWAGE TREATMENT PLANT UPGRADING WORK
CONTENTS
A.
WORKING METHOD STATEMENTS 1) 2) 3) 4) 5) 6)
B.
CONSTRUCTION METHOD STATEMENTS 1) 2) 3) 4)
C.
OVERFLOW CHAMBER AND DISTRIBUTION CHAMBER OPEN CUT SEWER PIPE LAYING METHOD INSTALLATION OF MILD STEEL PIPES PIPE JACKING METHODS.
RESOURCE REQUIREMENTS 1) 2) 3)
D.
SURVEY AND PEGGING SOIL INVESTIGATION SITE CLEARING EXCAVATION TEMPORARY SHORING AND SHEETPILING CONCRETING
MAN POWER MACHINARIES MATERIALS
WORK PROGRAMME 1) 2) 3) 4)
ADMINISTRATION TEAM QUANTITY SURVEYOR AND PROCUMENT TEAM DESIGN TEAM PROJECT TEAM
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
A.
WORKING METHOD STATEMENT
1/ SURVEY AND PEGGING
Before the commencement of the site mobilization and site clearing works we will appoint a licensed Surveyor to search for the Approved Plan of the contractual site with Client or the Survey Department. Upon having the necessary plan the survey team will conduct site survey to check for boundary stone and boundary demarcation by setting boundary peg to prevent potential encroachment into neighbouring land. Temporary Bench Mark (TBM) will also be set up at a few location inside and outside the contractual boundary for future reference during the construction period. Having successfully doing the above task they will conduct the leveling survey to determine the original ground level, slopes and terrain for the detail design and Construction purposes. Endorsed Drawing for the above survey works will be submitted to the client for their approval and safekeeping. The whole process of data searching, site surveying, pegging and producing of drawings will take about 1 week to complete. One gang three person survey team will involve in this process. Using the above survey data by licensed surveyor , our design team will proceed with their detail design and decide on their process flow, hydraulic head calculations, hydraulics profiles of each process and positioning of structures. The design team will then finalized their Layout and submit it to client and relevant authorities for approval. Upon approval of the layout drawing will be passed to the surveyor for the preparation of Pre computation drawing. Subsequently building alignment, invert levels and earthwork peg can be set up for construction.
2/ SOIL INVESTIGATION
In this specific job, the client has carried out the Soil Investigation reports, however if this scope is necessary the scope are as follows : A soil investigation specialist contractor will be appointed during the preliminary stage. They will conduct at least three borehole 30m deep within the contractual boundary to determine:a/ Soil type b/ Soil layer and dip c/ Soil properties d/ Standard Penetration Test e/ Ground water table __________________________________________________________________________________ Page No.3 of 14
GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK Other than the above test, Mackintosh Probe Test will also be conducted two numbers at every big structure position. One gang consist of five team member will involve in the above tests while the equipment required will be one set of Mackintosh Probe, one set of Borehole equipment, a small 415V Generator Set. The whole process of site works and data assessment will take about two weeks to complete.
3/ SITE CLEARING
Site Clearing works shall commence and coordinate with the site surveyor and soil investigator. This is because certain areas needs to be cleared to allow the smooth works of the other parties. All vegetation, weeds and tall grass or other unsuitable materials obstruct the working environment will be removed. It will be removed from site to our dumping yard. A backhoe, two number of lorries, 2 sets of grass cutter, 2 sets of portable water pump, a ladder one gang of five person daily workers will be employ to do this task .
4/ EXCAVATION
Upon approval of construction drawings, machineries and survey team will be mobilized to site. The survey team will establish survey control such as Temporary Bench Mark (TBM) and alignment control to mark the limit of excavation. The area that need to be excavated will be pegged and volume of excavation will be determined. Long arm excavator 300 series will be required for the deep of excavation more than six meter. The proposed structure that will require this type of excavator shall be the Jacking and Receiving Pit. For excavation less than six meter deep we proposed to use a normal excavator 300 series or 200 series depending on the volume of excavation. Excavated material will be hauled immediately to fill the idling area within the site or to be disposed to our own dumping site. Tipper Trucks will be employ to do the hauling. A backhoe and a bulldozer will be used to level the dumped excavated material. No excavated material shall be stockpile within the vicinity of an excavated area or a newly constructed structures to avoid slope failure.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK During excavation, a team of surveyor will regularly monitor the excavation level to avoid over cutting. For slope stability we propose that any excavation up to four meter deep shall have a gradient of 1: 1. Excavation more than four meter deep we propose to stabilize the slope with sheet piling or timber pile to avoid any untoward happenings. We expect the ground water table are quite high in this area, probably 2.0 meter below the original ground level. To ensure smooth excavation, we will provide water pumps to pump out water from the excavated area.
5/ TEMPORARY SHORING AND SHEETPILING
For excavation between 1 to 5 meters we propose to stabilize the slope by temporary timber shoring. For excavation of more than five meters we propose to stabilize the slope by installing temporary sheet pile. Used sheet pile will be hired for this purpose. For a small excavation pit such as sump, overflow chambers etc. we propose sheet pile FSP 3A to be driven 9 meter deep. A one ton vibro hammer mounted to the excavator shall be used to drive the sheet pile into position. Care should be taken to ensure the pile is properly interlocked. The sheet pile walls then need to be sufficiently braced with universal beam to avoid collapse.
6/ CONCRETING
During the preliminary stage we will scout the nearby potential concrete suppliers to this project. The potential supplier will be requested to submit their design mix for approval. Upon approval they will be required to carry out trial mix base on their design. The trial mix will then be tested to check their crushing strength at 3 days, 7 days and 28 days. The mix that conform to the strength requirement will be deem to be approved. All concrete batch arriving at site from the approved supplier will still need to be checked on their workability by means of slump test. A batch that fail the slump test will be rejected and asked to leave the site immediately. Cube Test will be conducted to every 50m3 of concrete supply at the same day or less if the day volume is smaller. For concrete casting volume up to 80m3 we propose to use normal mobile crane to hoist the concrete from trucks to the working area, volume more than 80m3 we propose to use pumping crane. Sufficient number of poker vibrator will be used to spread and vibrate the concrete. For a casting up to 80m3 of concrete, at least three number of poker vibrator will be used casting more than 80m3 shall require five number of vibrators.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
B. CONSTRUCTION METHOD STATEMENT
1.
SEWAGE RECEIVING CHAMBER AND DISTRIBUTION CHAMBER
The following steps will be carried out for the construction of the above structures : A/ BASE CONSTRUCTION 1) 2) 3) 4) 5) 6)
Setting out by a survey team to determine locations and peg the sump alignment. Hydraulic excavator or backhoe will execute excavation up to a certain depth Installation of sheet piling with a vibro hammer mounted to the excavator boom Hydraulic excavator will proceed excavation up to the base level Bracing of sheet pile wall Dewatering system shall be introduced where required to maintain the water level in the excavation pit to a minimum. 7) Level the base and place hardcore 8) Place binding concrete 9) Laying of reinforcement bar beginning with the slab starter bar, longitudinal and cross bar and wall starter bar. Cut and bent bar as per Bar Bending schedule will be used. 10) Formwork for the base perimeter including wall kicker will be installed. 11) Pre concreting inspection will be carried out at this stage. 12) Concreting will be carried out with skip hoisted using a mobile crane.
B/ WALL CONSTRUCTION Since the wall height is more than 7m we plan to construct the wall in three stages. Each stage will have the same construction method. 1) Laying of wall reinforcement bar 2) Installation of formwork to the inner side. Form tie will be fixed 3) Pre concreting inspection will be carried out to ensure the reinforcement follow construction drawing and specification. 4) Installation of formwork to the outer side of the wall to cover the reinforcement Form tie will be tightened. 5) Pre concreting inspection to ensure formwork is properly installed and supported. 6) Concreting will be carried out using a skip hoisted by a mobile crane.
C/ COVER SLAB 1) Installation of scaffolding to support the soffit formwork 2) Installation of soffit formwork 3) Laying of reinforcement bar. __________________________________________________________________________________ Page No.6 of 14
GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK 4) Pre concreting inspection to the reinforcement and formwork. 5) Concreting . By satisfying the above process the construction of a pump sump structure deem to have been completed.
D/ ROAD AND PAVEMENT The following steps will be carried out for the construction road and pavement. 1) Survey team will set out road alignment and ground level. 2) Filling and ground leveling using a backhoe and motor grader. 3) Laying of lateritic soil as subgrade to the required thickness 4) Compaction of laterite subgrade using a 12 ton vibro compactor . 5) Inspection of the compacted subgrade prior to receiving roadbase material. 6) Laying of roadbase (Crusher Run) using a backhoe and motor grader. 7) Compaction of roadbase using a 12 ton vibro compactor. 8) Inspection of the compacted roadbase prior to receiving wearing coarse material. 9) Premixing. 10) Road marking. By satisfying the above process the construction of road and pavement deem to have been completed. E/ DRAINAGE The following steps will be carried out for the construction of drainage. 1/ 2/ 3/ 4/ 5/ 6/ 7/ 8/ 9/
Survey team will peg the drain alignment Excavation to the required depth by a backhoe Compaction of the base Recheck the invert level by the survey team Laying of concrete base Laying Of the drain invert Concreting the drain invert Laying Sand brickwall to the required height Plastering
By satisfying the above process the construction of the drain deem to have been completed.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK 2.
OPEN CUT SEWER PIPE LAYING METHOD
The following steps will be carried out for the construction of sewer pipe on open cut methods : a. b. c. d. e.
f. g. h. i. j. k. l. m.
3.
Survey team will peg the pipe alignment Joint inspection and approval for the proposed route alignment with consultant and client. Installation of safety and road sign board Open cut for depth between 1 to 3 meters or temporary timber or sheet pile depends on the ground condition. Application of timber or sheet pile for excavation between 3 to 7 meters depth. Details shoring method statements available under items temporary shoring and sheet pile. Excavation of the trunk and stockpile of the suitable materials or disposal of the unsuitable materials to our own dumping area. Standby the water pump for dewatering purposes. The trunk should be always in dry condition for construction purposes. Place blinding concrete Installation of sewer pipe and jointing including pipe bedding following the client specifications. Backfilling the trunk with suitable materials and compaction Extraction of temporary shoring Backfilling and compaction of the relevant pavement layers around the excavated areas and road premix. Pipe testing
INSTALLATION OF MILD STEEL PIPES
The following steps will be carried out for the construction of M.S. pipes methods : a b c d e g
Survey team will peg the pipe alignment Joint inspection and approval for the proposed route alignment with consultant and client. Installation of safety and road sign board Open cut for depth between 1 to 3 meters or temporary timber or sheet pile depends on the ground condition. Excavation of the trunk and stockpile of the suitable materials or disposal of the unsuitable materials to our own dumping area. Standby the water pump for dewatering purposes. The trunk should be always in dry condition for construction purposes.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK h i j k. l m n
4.
Place blinding concrete Installation of m.s pipe and jointing including pipe bedding or trust block following the client specifications. Jointing of m.s. pipes either by welding method or mechanical joint. Backfilling the trunk with suitable materials and compaction Extraction of temporary shoring Backfilling and compaction of the relevant pavement layers around the excavated areas and road premix. Pipe testing
PIPE JACKING METHODS.
Please refer attached details pipe jacking methods as per specialist jacking contractor specifications.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
C. RESOURCE REQUIREMENTS 1/ MANPOWER Proposed overall manpower requirement shall be but no limited as follows:1/ 2/ 3/ 4/ 5/ 6/ 7/ 8/ 9/ 10/ 11/ 13/
One full time Project Manager One full time of assistant Project Manager Two Site supervisors One clerical clerk One quantity surveyor A team of survey gang cum daily workers One team of Carpenter consist of 3 peoples One team of Barbender consist of 3 peoples A team of Bricklayer consist of 3 peoples A team of Plasterer consist of 2 peoples One teams of pipe jacking machine operator One team for M.S. pipe construction
2/ MACHINARIES There are two categories of machineries will be employed for this project namely:-
A/ FULL TIME BASIS 1/ 2/ 3/ 4/ 5/ 6/ 7/ 3/ 4/ 5/ 6/ 7/ 8/ 9/ 10/
One no of 1.8 meter diameter Slurry Pipe Jacking Machine c/w hydraulic machine and accessories One Excavator series 250 One vibro hammer One backhoe Two lorry tipper One crane Two nos of 4” Water Pump One no of smaller Water Pump cum poker vibrator One no of Genset One nos of Bar Bending Machine One nos of Bar Cutting Machine One set of Survey Equipment One nos Hand Driller One nos of Compaction Machine Two no poker vibrator
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK B/ AS AND WHEN REQUIRED 1/ 2/ 3/ 4/ 5/
Concrete Pump Crane Mobile Crane Vibrator Roller Backpusher Paver machine
3/ MATERIALS Consumables materials shall be procured from various local suppliers but the most important materials is a Pipe Jacking Pipe will be design and supplied by approved JPP/IWK supplier such as ALIANSA, Hume or ACPI.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK
D. WORK PROGRAMME Upon receiving the letter of acceptance from the Government ( Employer ) we will mobilized our project team to carry out the following:-
1/ ADMINISTRATION TEAM The administration team will have the task to arrange all preliminary requirement of the contract. Performance Bonds will be procured through our Bank Facilities. It is expected the bank will issue Bank Guarantee on the Performance Bond within a month after Letter Acceptance date. Contractor’s All Risk and Workmen Compensation Insurance will be negotiated with our insurance agents. We expect the cover note will be issued within one week and the policy will be submitted to the employer within a month. The administration team will also procure items needs to be supply to the superintending officer stipulated in the contract. The items will be handed over to the Superintending Officer within one month from site possession.
2/ QUANTITY SURVEYOR AND PROCUREMENT TEAM. The team will have a challenging role to scout for subcontractors and material and equipment suppliers. They will cooperate with the design team and give feedbacks on market response to facilitate optimum design. A procurement programme and planning will be table and a cashflow programme will be issued. Upon site possession they will have to appoint immediately 1/ A licensed surveyor 2/ A specialist Soil Investigation Contractor 3/ A signboard Supplier During the construction stage the team task will be appointing subcontractors and suppliers. They will have to liaise with the site team to coordinate the supply of construction material, labor, machineries and equipments.
3/ DESIGN TEAM The design team will again review of all data available. New data such as current original ground survey, Soil Investigation data (mackintosh probes) will be gathered and analyzed. Upon receiving data from surveyor and soil investigation contractor the team will commence their detail design. We expect submission to authorities within two months.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK All in all the Construction Drawing will be ready within five months from the date of site possession. The design team will also acquire data from various authorities to check flood conditions And history of the area.
4/ PROJECT TEAM The project team will be station at site. They will be headed by an experienced Project Manager. Their first task is to get all the preliminary works at site executed smoothly. They will work together and supervise the survey team and soil investigation subcontractor. Hoarding, access road and site clearing will be under their responsibility. The Project Manager will then liaise with authorities to arrange for water supply and power supply. Superintending Officer site office, contractor site office , workers accommodation shall be erected with the approval of Local Authority. We expect all this building will be completed within one month from the date of site possession. The project Sign board will be erected at a location approved by the Superintending Officer. The Project Manager should maintain a number of daily workers to help him to do petty works such as pumping water, site clearing, grass cutting, survey control, pegging and so on. Site security and watching will also be under his supervision. Safety and Hazard sign are crucial at this project since most of the works involved deep excavation and construction on the road. The sign shall be advertised at strategic location to remind fellow workers and public of the safety requirement to enhance a safe working environment. The execution of works at site should strictly follow the work programme approved by the Employer. As part of a preparatory works the Project Manager will liaise with the Procurement team to get all construction materials to be tested and samples to be submitted for the Superintending Officer approval. Suppliers of concrete need to submit their propose design mix and arrange for trial mix to be tested and witness by the Superintending Officer. Once the Construction Drawing issued we will start excavation works for the pump station follows by others structure works, Meanwhile Barbenders will start fabricating reinforcement and Carpenters will proceed with the fabrication of formworks. Upon completion of the excavation work the structural constructions will take place. There are three separate teams working on this three separate site. While the construction of the pump station in progress the same process of excavation, and construction of sewer line will be in place. We will have three teams working concurrently on the open cut sewer line and two teams on pipe jacking works.
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GENERAL METHOD STATEMENTS FOR SEWAGE TREATMENT PLANT UPGRADING WORK Feedbacks of the work progress will be reported to the head office to update information to the procurement teams for their further actions. Mechanical and Electrical Equipment shall be procured to suit staggered completion of the structures. Prior to delivery all equipments that need factory testing shall be witness tested at the factory by the Superintending Officer. Mechanical and Electrical Equipment will then be installed at site to suit staggered completion of the pump stations. Upon satisfactory completion of the works, it will be Tested and Commissioned. By then we expect the Superintending Officer will gladly issue the much awaited Certificate of Practical Completion. The training module will be conducted to the client prior to the handing over of the project
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