This fabrication method statement covers the detailed procedure for fabrication and installation of any kind of steel structure & decking slabs. The procedure shall be read in conjunction with contract specification wherever applicable. Purpose of this procedure is to define fabrication and installation of steel structure and roof that shall be carried out under controlled conditions.
Responsibility of Fabrication Department
- Fabrication Manager is responsible for overall fabrication, quality and safety. Adopt a leading role with respect to Contractor’s quality and safety procedures.
- The Fabrication Manager shall ensure that the key personnel are well aware of the fabrication drawings and sequence.
- Fabrication Engineer is responsible for shop floor planning and production.
- Fabrication Engineer shall ensure that all welding must be done by certified welders.
- Safety Engineer shall be responsible for safe working environment & conditions. Coordinate with Fabrication Engineer to identify potential hazards before works and advice methods of safe working from new developments.
- QA/QC Engineer shall be responsible for ensuring the fabrication of steel are complying with approved shop drawings, specifications and ensure inspections are submitted based on ITP requirements.
- Fabrication Supervisor shall ensure that all fabrication works are carried out according to approved shop drawings.
- Fabrication Engineer and Supervisor shall be responsible for safe loading and unloading of structures to deliver on project installation site.
- Fabrication Engineer & Supervisor shall be responsible for safe lifting during installation process.
Responsibility of Project Department
- Project Manager is responsible for overall project execution, quality and safety.
- He will adopt a leading role with respect to Contractor’s quality and safety procedures.
- The PM is responsible for the overall implementation of this method statement. The Project Manager shall ensure that the key personnel are well aware of the specifications and method statement.
- CM / Project Engineer shall arrange all materials, equipment, safety related items & manpower & direct the Site Engineers & Foremen to resort appropriate action for the smooth execution of the works.
- Safety Engineer shall be responsible for safe working environment & conditions. Coordinate with Site Engineer to identify potential hazards before works and advice methods of safe working from new developments.
- Surveyor shall be responsible for setting out for levels, layout, and lines & establish top levels. Ensuring setting out books are properly maintained and filed when completed.
- QA/QC Engineer shall be responsible for ensuring that execution of works are complying with approved method statement; specifications, approved shop drawings and ensure WIR are submitted based on ITP requirements.
- Site Engineer shall ensure that all works are carried out according to approved shop drawings. He shall direct the surveyor for the setting out lines & levels in concurrence from the Construction Manager/Senior Civil Engineer.
Beams, Channels, Angles & Plates,
Fasteners including Bolts, Nuts , Washers, Anchor bolts & Screws,
G.I. Roof Decking Sheets
Structural steel Painting System
All Material for the columns, rafters and plates will be of Grade S275 JR or higher and material mill test certificate to be submitted for approval.
Bolts and nuts are of Grade 8.8 GI as per specification and mill test certificate to be submitted for client approval.
Consumables and paint to be purchased as per the specification and requirement and the batch certificates to be submitted for approval
Handling & Transportation of Metal Roofing Components
Fabrication/Project department will responsible transport and store components under dry well ventilated condition to prevent the formation of wet staining.
Fabrication/Project department will be responsible to take care handling, loading, unloading, transportation and storage and take precaution to minimize damage to painted surface.
Material inspections will be conducted upon delivery of materials to the site.
Project Manager, Project Engineer and Project Supervisor will responsible for site examination and survey for site facilities roads, materials storage etc prior to delivery and erection of any material.
All Shop & site workers shall be provided with complete Personal Protection Equipment (PPE) including body harness when working on heights.
All site workers shall attend Safety Induction and On-site Training to identify all Hazards associated with this particular work.
All Shop & site workers must be familiar with evacuation procedures including Alarm sounds and Assembly Areas.
Steel Structure Fabrication and Metal Roofing Procedure
Fabrication of beams and supports to be done in fabrication shop as per the approved drawing and site measurement. Necessary fabrication drawings will be prepared for in-house fabrication. The individual sections will be marked as per drawings, cut in size, punching of parts name, assembly, fit up, tacking and structural part name etc. will be done in sequence .
Weld Joints for the fabrication of beams and supports to be made as per the approved Welding Procedure Specification WPS. Joint fit-up and pre-cleaning to be done and make sure the joints are free from dust, oil and other foreign particles that could affect the quality of welding.
As heating and handling of electrode is very important to achieve good weld quality, ensure that baking and holding of electrodes are done as per the manufacturer instruction or as per WPS and they are transferred and kept at site in portable ovens maintaining required temperature (700C).
During the welding works, parameters as per the WPS such as welding current, voltage, travel speed, heat input, inter pass temperature and heat input to be strictly followed and monitored as per procedure. Proper inter-pass cleaning and full usage of electrodes to be ensured and final cleaning to be done by buffing or wire brush.
No grinding to be done on completed weld except on the starting points and the completed weld shall be free of arc strike, slag, open porosity, spatter, lack of fusion, undercut, and excess reinforcement. Daily weld production report to be prepared in proper format and submitted to the client for approval.
Workmanship Control Procedure
- Engineering department will issue approved client drawing for fabrication to QA/QC and fabrication department.
- Fabrication manager makes cutting list as per approved fabrication drawing.
- Fabrication engineer will take material from store as per cutting list.
- QA/QC Engineer will check lay-out before cutting as per cutting list.
- Fabricator will make fit-up as per approve drawings.
- QA/QC Engineer will inspect fit-up as per approved drawings.
- Fabrication supervisor will assign certified welders for welding
- QA/QC engineer will inspect welding works as per specified standard.
- Fabrication engineer/Supervisor will supervise final cleaning.
- QA/QC engineer will make final and release for blasting & painting.
Roof System Installation
First Floor Level
Mechanical key for transferring horizontal shear and for preventing vertical separation.
The quantity of shear studs, its spacing etc. will be according to the approved calculations and layout.
Provide decking with shear studs and hold-down lugs to achieve composite action between decking and concrete fill.
Z Purlins will be installed above roof beams.
Sandwich panel of required thickness as per approved material and specifications will be fixed to the purlin by using sheeting screw.
Required flashings/Gutters etc will be fixed to ensure water drain.
Steel Structure Installation Sequence
A typical installation sequence shall be as follows:
Alignment and survey works will be done first with a calibrated survey instrument.
The anchor bolts that hold the steel structure, fixed on a base plate will be done. These are either cast-in RCC footings or site-fixed into RCC walls/slabs/columns using approved chemicals.
Drilling of holes on existing structures will be done by using drilling machine with concrete bit. Drill depth to be as per manufacturer instructions. Pull out test to be conducted and drilling reference to drilling material should be clearly specified.
Erect the columns by using appropriate lifting devices and check the verticality of the columns and make it truly vertical. Provide shim plates below the base plate if required.
Start the erection of connection beams after completing all columns in a frame and connect with bolts.
The full tightening of the bolts can be done only after the all connection beams are erected in single frame.
Roof decking works such as fixing of shear studs will be done from workshop and sheet fixing will be done in the site after erection of the structure is complete.
Z purlins will be fixed to the roof beams with purlin cleat connections.
Roof sandwich panel will be installed over the z purlins and fixed with sheeting screw.
Required flashings and gutters will be provided to ensure easy drain.
Cleaning and touch up will be performed after finalizing erection and roofing works.