Before starting the Roof Steel Truss Installation necessary Scaffolding or working platform shall be provided with green tag to reach and work at the height safely.
Marking of Layout: The base plate level and the center line of the Truss / Column shall be marked based on reference datum and coordinate points given by main contractor surveyor. All locations to be marked as per approved drawing. All locations to be ensured for distance between Truss / Column and level as per approved drawing.
Assembly of Truss/ Platform Preparation for Truss Assembly
The separated truss shall be assemble on platform at site before erection. Platform should be prepared with level and measurement as per given in drawing to join the truss as one unit. Platform should be placed in crane reachable area.
Truss Assembly on Platform
Site measurement to be taken and truss length to be confirmed before truss assembly. Truss to be placed over the platform to join by maintaining the level and measurement. Check the surface of the truss in a same level, dimension then tack weld to be done. After completing the tack weld in all joints, the truss is to be checked and ensured for the straightness and dimension.
The joints to be properly arrested to withstand heat formation during welding and to resist against any deformation. Welding to be done at the perfectly aligned, tacked and arrested joints. Fluxes to be removed from welded surface. After completion of the welding the arrested supports should not be removed immediately. The supports at joints to be removed after ensuring the beam joints are in good condition and keep main supports till lifting. The welding to be thoroughly clean and paint touch up to be done after welding inspection. Welded joints to be inspected as per the procedure.
Painting of Assembled Truss
The welded surface to be cleaned properly and ensure free from any particles like oil, grease, etc. Paint to be applied as per the procedure. Inspection to be raised before erection for assembled truss.
Installation of Column
Scaffold to be arranged to work at column height safely. Embedded plate / insert plate in which column base plate resting level to be checked and marking to be done.
The part number of column to be identified and shifting to correct location. Column to be erected by lifting using crane with suitable capacity lifting belts. Column should be tied with rope to guide and place into correct location. Column height and measurements to be ensured before tightening of bolts.
Base plate bolts to be properly tightened. Crane belt to be removed after ensuring the column fixing is rigid. Scaffold to be arranged to work at truss height safely. Embedded plate / insert plate in which truss base plate / connection plate resting level to be checked and marking to be done. Stopper / resting plate to be welded at bottom of connection to place the truss in right location during erection. The part number of truss to be identified and shifting to correct location.
Before lifting part number and position of truss to be ensured. The assembled truss to be lifted for installation using cranes with suitable capacity lifting belts. Ensure truss should be free from any tie, bond or weld with other objects before lift. Place the belt on truss where the load will distribute equally on both sides. Tie the rope on both ends to guide and position the truss in correct location. Lift the truss through crane and place at actual fixing location.
People movement should be stopped in truss lifting area and barricading all around lifting area. Match the truss with marking in embedded plate / insert plate and check for measurement and alignment, tack weld to be done. After ensuring level and measurements full weld to be done at connection. Crane belt to be removed after ensuring welding and proper temporary tie support. Connection welding to be inspected as per procedure. All the truss to be join, lift and fix in the same manner and check for alignment.
Bracing Installation
After ensuring the alignment of the truss, mark the bracing locations in all truss as per the drawing. Fix all the bracing with tack weld and ensure proper alignment of bracing. All the tack welds to be completed with full weld. Paint touch-up to be done at welded locations.
Temporary tie support welded during installation of truss to be removed and paint touch up to be done. Bracing welding to be inspected as per procedure. Inspection to be raised after ensuring all members installation, proper fixing and tightening of fasteners, paint touch up.