The purpose of this civil work method statement is to cover the activities involved in the fabrication and installation of the steel reinforcement rebar in the project considering the quality and safety requirements.
Scope of the method statements covers the activation of the rebar shop drawings and on site activities and does not cover the rebar cut and bent or fabrication works if any in an off-site factory.
The document is part of the project quality control procedures related to the concrete work for the construction project.
Objective of this document is two folds i.e. to demonstrate total quality commitment in implementing, managing and executing of the works for the project and to assure the client and their project managers and Engineer the confidence that the contract requirements will be satisfied by contractor in every aspects of the works.
This document summarizes the general details of the quality assurance plan for rebar work including:
- Project team organization
- Shop Drawings
- Testing and inspection
This document should be communicated reiterated, regularly reviewed and developed to suit changing condition, standards and technology as the project site situation requires.
Roles & Responsibilities
Site Manager will be responsible for the fabrication and installation operations. His duty also includes coordination with Engineer for inspection prior to concreting works.
QA/QC Manager will be directly responsible for assuring compliance with the contract documents. His duties further include:
Implementation of the Quality control plan to ensure accurate and adequate inspection compliance with contract documents and direct corrective action upon any occurrence of noncompliance to contract documents.
Record all Quality Control activities including inspection and take appropriate measures to correct defective works.
If the tests for rebar are required, Engineer will select the rebar’s samples at random and send to the approved laboratory test in accordance with the contract documents.
Test reports conducted by approved independent Testing Lab will be in duplicate, with copies going to the Engineer and contractor office.
Implementation of the project quality control plan will be the responsibility of the Project Manager who will have total support of the company’s management and staffs for review and approve all documents and letters related with the reinforcement works and submitting as necessary to consultant/client.
Sequence of Work for Rebar Fabrication and Installation
The following types of products have been specified for each structural element:
Reinforcing bars: Steel deformed bars conforming to the requirements of ASTM A615.
Welded wire Fabric: the requirements of ASTM A497.
Type Diameter (mm) Use
High Tensile Bars 8, 10, 12,14,16,18,20,25,32 Main bars, etc.
The following points need to be given attention to in the process of shop drawings:
Normally, development length shall comply with the requirements on S-01 of the structural drawings.
Requirements for the minimum concrete cover on rebar and it’s deciding factors shall be as per the contract documents.
Splicing of rebar will be normally lapped splice.
Openings in concrete beams, walls and slabs shall be reinforced with additional rebar and to be as specified in contract documents.
Bar Bending Schedule
From the approved shop drawings the Bar Bending Schedule is prepared.
This enables the weight of standard length and cut to length bars to be taken off.
From this take-off the rebar order can be placed.
Rebar Order, Delivery and Storage
The various suppliers of rebar will be submitting the mill certificates on delivery to the site. These will be forwarded to Engineer with the yield stress tests which are carried out from random bars and tested at an approved independent test laboratory.
Mill certificates will be reviewed and listed together with the heat numbers marked on the steel (rebar) and will be correlated against the delivery documents.
Rebar will be stored at the stockyard in a neat and tidy manner and according to contract documents to make it possible to keep track of the specific delivery from the factory.
Moreover, rebar will be appropriately sheltered from rain water and dusts to avoid adverse environmental effects of rusting and others.
Most of rebar will be fabricated at approved factory for the project. The rebar’s fabrication area is located at site for the missing and shortage purposes. Rebar’s will be cut and bent to the correct details based on the approved shop drawings and bar bending schedules. In case of shortage and supply issues in the market the rebar fabrication will be carried out at site.
Rebar’s which have a diameter of 12mm or greater will be fabricated by using the bending machines with approved fabrication tolerance under supervision of rebar subcontractors.
Fabricated rebar will be stored in a neat and tidy manner and according to contract documents.
The cut and bent rebar will be made up into bundles of the appropriate weight and then transported to the site according to the installation schedule.
Each bundle of rebar shall be shipped to the site with a tag indicating the relevant information.
Unloading & hoisting of rebar on site
Tower crane(s) will be used for the moving and installation of the fabricated rebar.
Some of the rebar’s will be hoisted directly to several distributed points on the floor or to the working platform where rebar’s installation works are taking place and others will be hoisted after being assembled at site.
Rebars Installation Procedure
The rebar’s installation procedure will be supervised by the site engineers of main contractor. Each position of site engineer has a duplicate staff, thus night time rebar installation will cause no problem in items of supervision.
Columns and beams rebar’s will be assembled as far as possible mainly at the Stock Yard and then hoisted to the designated place by tower cranes while trying to hold the rebar configuration in place.
If necessary, supplement bars or angles will be added temporarily to increase rigidity of the prefabricated rebar.
Because of the congestion of rebar’s within column, a part of beam rebar’s still need to be assembled in place.
Column rebar will also be assembled to some extent at the Stock Yard.
Column main bars will be tied completely with column ties before being hoisted by tower cranes and positioned to the designated places.
To hold pre-assembled rebar’s in place tying shall be done.
Wall & slab rebar’s will be usually hoisted as bundles carried from the stock yard and installed manually by steel fixers.
However, if the site condition allows, a portion of wall vertical rebar might be temporarily assembled at the stock yard for efficient installation.
Rebar will be tied firmly with approved wires at the designated spots.
Approved supports, chairs and spacers with various shapes and dimensions will be placed underneath or at sides of rebar’s to ensure the correct concrete cover required in the contract documents for each structural element.
The prefabricated rebar cages shall be tied firmly to keep rebar configuration undisturbed during the hoisting operations.
One mechanic will be available standby to service any breakdown of the tower cranes.
Even if one tower crane is completely out of operation due to mechanical troubles, another tower crane can serve for hoisting rebar’s, allowing that the productivity is not impacted considerably while repairing work takes place.
The rebar’s which have been delivered to the stockyard will be released for fabrication only after it is confirmed that the relevant independent tests exceed the requirements.
Night Time Works
Sufficient manpower and equipment will be provided for all night rebar works including standby service support personnel (e.g. tower crane operators, mechanics, electricians, etc.)
Adequate lighting will be provided for all work areas in order to ensure safe and efficient operations during nights.
Quality Plan for Reinforcing Bars
The control of quality for reinforcement works on project is covered in five separate areas and the quality checks will be sequential, following each step as follows:
- Review and study contract drawings and prepare shop drawings accordingly
- Prepare basic schedule, purchase order, obtain mill certificate and deliver to site
- Cut and bend rebar according to prepared bar bending schedule
- Prefabrication of wall, column and beam cages
- Site installation
Reinforcing bars will confirm to the requirements of ASTM A615 and welded wire fabric to the ASTM A497 as specified.
All delivery note will be filed with the relevant mill certificates by contractor’s staff to keep track of rebar. Each delivery note of rebar will be marked with the following relevant items:
- Delivery Date
- Delivery note Number
- Heat Number
- Type of Rebar’s
- Transporting Vehicle Number
- Number of Bundles
- Total Weight
- Fabricated Rebar’s
Each bundle of the fabricated rebar to be transported from the fabrication areas to the site needs to be marked and tagged with the following information:
- Type of Rebar’s
- Place to be Installed
- Total Weight of Bundle
However the traceability of each piece of fabricated rebar cannot be achieved in the practical construction circumstances.
Control of Non-Conforming Products
In the actual situation on the site, if concrete cover is assumed not enough (ex. Starter bars or dowel bars installed of the right position), a proper means to gradually adjust the position of rebar will be determined based upon consultation and approval of Engineer.
As a matter of course, remedial actions will be taken immediately prior to concrete pouring or formwork closing, when improper installation of rebar is pointed out in inspections.
Site Rebar Inspection Plan
The exact date and time of site inspection prior to formwork closing or concrete placement will be informed to Engineer as early as possible, by using the approved forms.
However, in the case of tight schedule of the project, arrangement of inspection time needs to be flexible.
The rebar work checklist will be provided to inspect rebar installation. This sheet will be filled by the inspection staff who performs the internal inspection and also attends the inspection by consultant.
Corrective actions on the improperly installed rebar will be directed to subcontractors based on the items on the inspection sheet.
When a significant omission or inadequacy of length is discovered during the inspection, corrective actions will be taken and that part or rebar’s will receive inspection again before commencing concrete placement or closing shutter.
Rebar Laboratory Testing Plan
Rebar testing at an approved independent laboratory will be performed as per the contract documents.
Three samples for tensile strength, one for bending and one for re-bending will be tested for at least each diameter of rebar from each manufacturers and each 500 ton to be delivered to the site.
Consulting engineer will do sampling from the bundles or rebar stocked in the site.
The rebar’s which have been delivered to the site will be released for fabrication only after it is confirmed that the relevant independent tests show successful results.
Mill certificates from the manufacturer, which include tensile and bend test results, will be submitted to the Engineer with every delivery of rebar’s to the stockyard.
All test results and mill certificates will be regularly submitted with a summary table to consulting engineer. The original test results will be filed by consulting engineer.