1. PURPOSE
The purpose of this general method statement is to describe the construction procedures for the isolated pile cap and pad foundations. Large raft foundations will be covered in specific foundation method statements and are not included in this document.
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2. SCOPE
The works will incorporate the procedures necessary to execute the following items:
Preparing of Work, Survey& Setting Out, Excavation, Dewatering, Pile (If Applicable), Blinding Concrete, Foundation — Rebar- Formwork — Concrete, Embedded Items, Back fill, Pedestal
3. DEFINITIONS
Client = ABC
Contractor = SBC Responsible in the supervision of the sub-contractor who will perform the construction work and all related activities as outlined in this procedure
Sub-Contractor = XYZ Responsible in the execution of the construction work as well as the tests required in accordance to this procedure
4. RESPONSIBILITIES
4.1. Construction Manager and Senior Engineer
Construction Manager and Senior Engineer responsible in ensuring the implement of construction procedure and method statement, the Quality Control of work, Supervise the work and reporting the progress of work to Site Manager.
4.2. Safety / Environmental Officer
Safety / Environmental Officer responsible in ensuring that all activities are carried out safety patrol at the site, Establishing the site safety plan, conducting continuous safety inspection and stop any work deemed unsafe and a risk to personal, taking action to rectified the unsafe condition and report to project manager and preparing the notes of safety meeting.
4.3. QA / QC Engineer
QA / QC Engineer responsible to monitor the execution and performance of the works in relation to this method statement, approved drawings and material specifications; detect and report non-conformance; ensure that all non conformance products or activities identified are reported; propose the corrective and preventive action where possible and appropriate and record the completion the Non Conformance.
4.4. Site Engineer & Foreman
Site Engineer & Foreman responsible in all activities on site are carried out in accordance with the schedule and the construction drawing and take care all worker to be work with their responsibilities and make a decision when some non-conformance occurring their report to senior engineer
5. SAFETY
Refer to the site safety policy for general safety controls. One of the main aspects of this procedure is Safety and Health Control. This is to control occurrence of injuries as well as damage to equipment and properties during the entire construction period. In order to ensure a safe working environment during the entire construction period, the following safety measures will be implemented:
5.1. Machinery and Equipment:
- Prior to using any machineries /equipment at site, it shall be inspected and certified by qualified person.
- Periodic Preventive Maintenance shall be made on all equipment and machineries.
- All operators and drivers are to be equipped with valid driver's/operator's license or permit from concerned government agency.
- Only authorized drivers or operators will be allowed to operate machineries or equipment.
- Only authorized signalman shall be assigned together with the operator or driver.
- All lifting equipment as well as its accessories such as sling wire, nylon sling, shackles, chain blocks crane hook and latch shall be inspected periodically.
5.2. Personal Protective Equipment:
- Personal Protective Equipment (PPE) shall be issued to all workers such as safety shoes, hardhat, working gloves, earplug, safety goggles (if required) and safety belt and or safety harness for workers who will be assigned in elevated places 2.0meter and above.
- Wearing of the basic PPE shall be enforced fully.
5.3. Safety Arrangement during the Foundation Work:
- Emergency Action Plan
Note: All new recruits shall undergo proper orientation and safety induction before they are deployed at site for work.
6. WORK PROCEDURE
6.1. Preparation of Works:
- Foundation works will not commence until confirmation that all pre-construction planning and safety checks are completed.
- The supervisor shall be familiar with the latest construction drawings and method statements.
- Plant and equipment requirements will be assessed on a case-by-case basis for each foundation location and agreed with the Construction Manager prior to starting the works.
6.2. Survey and Setting out
Before work starts survey department will establish baselines and benchmarks from which co-ordinates and elevations will be taken to set out the foundation works.
6.3. Excavation
- Excavations will generally be executed in open cut to the size, slope and elevation shown on the construction drawings and/or design calculations.
- Survey will set out and check edge slope and bottom founding level of excavation.
- Excavation will be carried out with excavator and the excavated material loaded directly into dump truck and transported to temporary stockpile area.
- A small bucket or manual digging will be used when excavating between piles.
- The final bottom founding level under each foundation will be inspected by QC and tamped or compacted as per design requirements before pouring blinding concrete.
- For a description of all related work activities refer to MS0501 -General method statement for open-cut excavations.
6.4. Dewatering
- From the site soil report the relative groundwater level is approx. -2.5m below existing ground level
- During excavation and after reaching the required excavation level a dewatering system will be installed as required and any water discharged to the vicinity drainage
- For a description of all related work activities refer to General method statement for dewatering excavations.
6.5. Piles where applicable
- Following final excavation the piles will be cut down to design pile cut off level.
- Removed sections will be lifted out and taken to designated disposal area.
- After cleaning, the pile head Treatment will be done to connect pile to foundation.
- For a description of all related work activities refer to Method statement for pile cut-off.
6.6. Blinding Concrete
- Bottom of the excavation should be dry and tamped or compacted to a uniform level before pouring the 50 mm thick lean concrete blinding layer.
- For a description of all related work activities refer to General method statement for concrete.
6.7. Foundation
After QC inspection of the prepared founding level and lean concrete base layer then construction of the foundation will follow.
- Rebars will be cut and bent on site in line with the agreed construction sequence.
- Installation of rebar will begin as soon as blinding concrete has hardened enough for trafficking (normally 12 hours)
- A mobile truck crane and/or manual workers will be used for rebar installation.
- Rebar placement sequence will follow the latest rebar construction shop drawings.
- Suitable concrete spacers will be used to achieve the desired covers and additional rebar spacers will be installed to maintain support of top steel and any cast-in items.
- All pedestal column starter bars and cast-in anchor bolts will be accurately located and securely fixed in the correct position.
- Location, spacing, verticality and cover shall be checked during the installation process and QC will make a final inspection prior to calling up concrete.
- For a full description of all work activities refer to General Method Statement for Rebar.
- The form work system to be adopted for each foundation type and size will be as specified in approved calculations prepared by the Temporary Works Design Engineer. The different types of form work for site installation purposes are summarized in Table Appendix
- Plywood sheathing with timber and steel props will be used for form work and manual labor will be used for lifting and placing according to survey-lines of the foundation outline.
- Approved form release agent is applied prior to lifting-in and erection of the clean forms.
- Forms are connected tightly together and braced to the excavation profile or waling in the case of a sheet pile wall.
- For a full description of all work activities refer to General Method Statement for Form work.
- 1 no concrete pump will be available (with back-up pump) for placing concrete at a rate of around 35-40m3/hr. In some cases, pouring concrete will be done by bucket and 25T mobile crane at a rate of 1 0-15hr.
- A minimum of 4 nos of 50mm vibrators shall be used for compaction.
- Unless agreed otherwise the foundations will be poured at one time in layers, starting from the center and spreading out to each side. CHECK IF CORRECT!
- Keep concrete alive without performing any cold joints.
- Manual tools and float are used to finish the top surface.
- For a full description of all work activities refer to General Method Statement for Concrete.
6.8. Embedded Items
- All embedded items and cast-in anchor bolts shall be placed to the specified installation tolerances shown on the construction drawings.
- Special care will be taken to place and maintain embedded materials to the proper setting location to prevent movement during the progress of the work and to tamp concrete thoroughly around them.
- For a full description of all work activities refer to General Method Statement for embedded items.
6.9. Repair and Touch-up.
After striking of forms a QC inspection will be conducted to decide whether any repairs to the concrete surfaces are necessary.
For a full description of concrete repair procedures and materials to be used refer to General Method Statement for Concrete repair and touch-up.
6.10. Back filling
- Backfilling operations will be executed in two (2) stages using suitable excavated sand material.
- The first stage fill will be placed up to the top of foundation level and will commence as soon as formwork has been removed and QC inspection of foundation is approved.
NOTE: - If this method is adopted then curing f foundation will be done using ??????? curing compound.................................................................................................................................................................................................................................................................................................................................................................................................................................
- Backfilling will be done in loose layers not more than 250mm in thickness.
- Suitable vibrator plate/rollers and/or water will be used to achieve the compaction requirements for each layer field density test will be performed to check the soil compaction to 95% maximum dry density.
- Any embedded cable way conduits and earthing/grounding wires, drainage pipes and trenches etc. should be installed simultaneously with the backfilling laye 18.
- After completion of the concrete pedestal then the second stage fill will be carried out up to grade level below proposed finished ground level
- For a full description of all work activities refer to General Method Statement for backfilling of excavations.
6.11. Pedestal
- Pedestal columns vary in height between??? ????? and
- Heights exceeding ????????? will be cast in two (2) lifts.
- Formwork will be made using plywood form panels in sizes to suit manual installation and dismantling.
- All construction joints will be properly prepared at location indicated on the construction shop drawings.
- For general construction details and work procedures refer to General Method Statements for Rebar, formwork and concrete.
7. TOLERANCES
As final design drawings and/or Main Contractors instructions.
8. REFERENCES
- Specification: Client's Technical Specification for Civil Works, Section 6 — Material and Workmanships Sub-section 6.4 "Concrete Work".
- Safety provisions: Refer to Site Safety Plan.
- Related Method Statements:
- General Method Statement of Concrete General Method Statement of Reinforcement General Method Statement of Formwork General Method Statement of Concrete Repair and Touch up Drawings: Refer to latest "For Construction" drawing list.
9. APPENDICES
- Appendix A: Activity Organization Chart
- Appendix B: Emergency Action Plan
- Appendix C: 1. Foundation Location Plan
- Foundation Schedule
- Foundation Construction Sequences
10. EXHIBITS
Title: Foundations
Appendix A: Activity Organization Chart.
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