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Concreting of super structure


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Concreting of super structure

  1. 1. Table of contents 1. General. 2. Management Organization Chart 3. Sequence of works (beam & slab). 4. Formwork design. 5. Construction joint treatment. 6. Re bars fabrication & setting. 7. Installation of embed item. 8. Placing of concrete. 9. Compaction of concrete. 10.Removal of formworks 11.Curing 12.Protecting against raining 13.Electricity 14.Equipment & Manpower 15.Safety measure Appendix A. General plan and elevation B. Typical formworks & Scaffolding arrangement. C. Calculation for formwork and support systems D. Safety Procedure 1. General
  2. 2. This method statement describes how we carry out the concrete works of superstructure in building works. Concrete class shall be approved ready-mix concrete Grade 35MN/m2 Please refer to Appendix A for general plan and elevation of three main building. 2. Management Organization Chart Mr. N.N.Hai HSE Manager Mr. Tran Thanh Minh Site Engineer Mr. Hoang Hung Site Engineer Sub Contractor Sub Contractor 2.1 Project Manager Mr. T. UCHIDA Project Manager Mr. A . IKEGAMI Construction Manager Mr. A.M. Cabonce QA/QC Manager Mr. K.Miyara Chief Engineer Mr. P. C. TRUNG Chief site Engineer Mr. Dang Trong Dung Site Engineer Sub Contractor · To oversee and control all aspects of the Piling activities, and dictate schedule requirements · To ensure that all field staff are fully aware of the requirements of this method statement, and that these requirements, in all respects, are fully implemented. · To ensure that Safety and Environmental procedures, particularly, are in place before activity commences, and strictly complied with, throughout the duration of concreting works.
  3. 3. 2.2 Construction Managers, directly reports to Project Manager. · To oversee all construction works, with respect to schedule. · To ensure that all field staff follow the requirements of this method statement, including quality control and HSE. 2.3 Chief Engineer, reports to Construction Manager · To ensure that all relevant preparations have been made. · To ensure that all provisions of this method statement are followed. · To ensure that all quality inspection is carried out and record taken, if required. · To ensure that all necessary safety and environmental precautions are in place and that all workers under their direct control are fully aware of all procedure requirements · To control execution of the entire activity 2.4 Site Engineer · To assist Chief Engineer to control the Subcontractor for all activities relative to this method statement. · To ensure safe working environment at all times, during Subcontractor execution of concreting works. 2.5 Surveyor · To give control points & grid line to Subcontractor for concreting works. · To supervise Subcontractor and conduct survey checks from time to time. · To carry out all surveying work and to ensure all required records are taken and maintained. 2.6 QA/QC department · To oversee construction activity with respect to quality control. · To ensure quality procedures has been followed.
  4. 4. · To ensure that all required inspections have been carried out and that records, if required have been taken and properly stored. · Advise the laboratory and Site Engineers to control the quality of works. 2.7 Health, Safety & Environmental department · To monitor that all the working activities are executed in accordance with site safety procedures. · To ensure that precautions with respect to Environmental matters have been implemented on site. 3. Sequence of works (beam & slab). Setting Staging for Construction Area Setting Support & Bottom Formwork Construction Joint Treatment Inspection for Construction Joint Assembling re bar Inspection of re bar Setting Side Formwork
  5. 5. Inspection for casting concrete Placing Concrete Curing Stripping of Form Stripping Support and Prop after Getting Design Strength 100% 4. Formworks Design Formwork shall be set in correct position following specification and the approved structure drawings. Please refer to Appendix B for Typical formworks & support for 2nd floor slab. Formworks and support is calculated as shown in Attachment C Approved form oil will be applied to form surface prior to installation of form. 5. Construction joint treatment All construction joints will be chipped to remove cement sand surface to make rough surface.
  6. 6. In some cases, approved retarder for concrete surface will be used as another method to make construction joint properly. 6. Rebar fabrication & setting Approved re-bar type will be delivered to site and it will be inspected & tested prior to use. Re-bar shall be cut and bent according to the approved schedule at the site workshop and transported to site by truck. After delivery to the site re-bars shall be fixed according to specification and approved drawings by Engineer or Consultant. Rebar shall be inspected by Engineer or Consultant prior to install of next layer or formworks. Any mistake rebar will be replaced or repaired by approved method. Approved concrete spacer shall be used; its concrete grade shall be 35 MN/m2. 7. Installation of embed item All the embed item showing in the drawings shall be firmly installed in correct position. 8. Placing of Concrete Approved ready-mix concrete will be transported from batching plant to the site by mixer truck. During transportation & waiting time the concrete shall be kept continuously agitated. From mixer truck concrete will be poured to casting location by concrete pump or by bucket. The height from discharge position to casting level shall not be over 1.5m. On each concreting day and for each grade of concrete mix, samples shall be taken. When samples are taken at sites, samples shall be taken for every 24m3 of concrete or part thereof, of each grade of concrete. Minimum requirement of sample
  7. 7. - Each concreting day - Each part of structure (each building) - After filling above condition, samples shall be taken for every four mixer or agitating truck (20~24m2). 9. Compaction of Concrete. Concrete after pouring to position shall be compacted by immersion vibrator. Proper staging for vibration works will be arranged. Wooden or rubber hammer also will be used as external vibrator in some cases. 10. Removal of formworks Form works removal shall be accordance with specification Clause 4.20 or as proposal hereunder. - All vertical or side formworks : 12 hrs (The period shall commence from the time of last pour of concrete) - Soffit formworks to slabs & beams : 3 days ((The period shall commence from the time of last pour of concrete) - Props to slabs & beams: Requirement in Specification is 14 days. We propose that before remove props we will carry out testing for cube sample, whenever if we get 100% designed strength of concrete we will remove props (After skirting of formworks, props shall be immediately put up to support the structure) - Props to cantilever slabs & cantilever beams: Requirement in Specification is 21 days. We propose that before remove props we will carry out testing for cube sample, whenever if we get 100% designed strength of concrete we will remove props (After skirting of formworks, props shall be immediately put up to support the structure)
  8. 8. * Testing for purpose of removal formworks will be carried out at 7th days after finish casting concrete. All tie rod holes & defects on surface will be repaired following approved method. 11. Curing. After removal of form works, concrete shall be cured minimum of 6 days according to TCXDVN 391:2007– Requirements for Natural Moist Curing, apply for Area C of Viet Nam. Curing of concrete will be carried out by spraying water periodically to the surface of the newly placed concrete. Jute bag or nylon sheet shall be used to cover the concrete surface for keeping wet. Water to be used for curing and cleaning works is portable water from local authority. Approved curing compound also will be used in several cases. 12. Protecting against raining. Against raining, plastic sheet shall be prepared to cover over the concrete area before concreting. 13. Electricity Electricity will be supplied by generators on site. 14. Equipment & Manpower a)Equipment Equipment Unit Quantity Mixer truck Nos 04 Vibrator Nos 03 Concrete Pump No 01 Generator 15KVA No 01 Generator 10KVA Nos 02 Bucket Nos 10 Showel Nos 05 Trowel Nos 05
  9. 9. b)Manpower Description Unit Quantity Supervisor No 01 Surveyor Nos 02 Foreman No 01 Electrician No 01 Worker Nos 10 15. Safety measure Please refer to Appendix D for Safety Procedure when working at high position