WORK PROCEDURE FOR MODIFICATION OF BASE PLATE BOLT HOLES-MECHANICAL
Bolt hole distance discrepancy
• Bolt Holes as per coordinates actual distance and site condition is at 4966 mm, 4963 mm, 4971 mm and 4965 mm. Design coordinates dimension is at 5000 mm.
Correspondingly, Anchor Bolt Holes Dimension has a distance -34 & -37, and -29 & -35. Reading movement flows from East to West Side.
• Actual Base Plate Anchor Bolt Holes at fixed side shall be Plugged welded and provide new bolt holes to suit actual site condition dimensions to install as per new diagram.
Plug-welding on Fixed Side
Fixed side base plate bolt holes shall be clean and remove the paint surface using pencil grinder prior to start of plug welding.
Plug weld the existing bolt hole of base plate at fixed side portion in accordance with AWS-D1.1.
Smoothen the surface after plug welding by using grinder & power brush.
For the sliding movement of sliding side, both side of Anchor Bolt have 22 mm space as minimum according to drawing.
Fabrication of new bolt holes at Fixed Side Base plate
Lay-out and mark the new bolt holes locations and conform bolt hole sizes as per latest approved for construction drawing.
Provide line marking on plug welded holes portion to determine the distance between new holes and plug welded holes.
QC inspection verifying/checking the lay-out dimension.
Drill the required bolt holes using magnetic drill or annular cutter.
Bolt hole enlargement
Reaming of bolt holes by using pencil grinder to satisfy the required dimensions as per construction drawing.
Touch-up painting of the affected area.
Painting of Base Plate Holes
Paint materials for each coating system shall conform with same manufacturer. Painting shall be in accordance with client requirement.
leaning & Surface preparation prior to QC Inspection for the application of liquid coating system.
Apply necessary coats as per requirement of paint system no. APCS-1B.
After curing for each coating of Primer to Top Coat, painting QC Inspection shall be done to carry out the succeeding process.
SAFETY PRECAUTION DURING MODIFICATION OF BASE PLATE BOLT HOLES
1 Approved work permit should be obtained prior to start any repair works.
2 Work execution shall be carried out in accordance with this method of statement.
3 Erection crew must carry out a safety risk assessment prior to start of any new activities.
4 The necessary manpower inclusive of supervisory staff, tools, equipment, materials, and other resources required must be made available and ready to use.
5 Workers should wear their PPE’s always.
6 Good housekeeping must be maintained in the duration of works.
7 Safety Supervisor/Engineer shall monitor compliance of entire working crew to safety procedure until the work is fully completed.
8 Contractor/Company shall make sure that all be incident and injury free.
TOOLS AND EQUIPMENT DURING MODIFICATION OF BASE PLATE BOLT HOLES
Tools and equipment needed should be in good condition and must be checked by Mechanical Supervisor/Safety Officer prior to use in the construction area. These Includes but not limited as below:
1 Clamps
2 Cutting torch/gauging
3 Grinder
4 Welding Machine
5 Mobile Crane
6 Man Lift
7 Fork Lift
8 Chain puller/blocks
9 Wrenches
10 Nylon Slings
11 Hand tools/jigs
12 Hydraulic jack
13 Annular Cutter/ Magnetic Drill
Industry Codes and Standards
1. AISCAISC Code of Standard Practice, Specification for Structural Joints Using ASTM A325 or A490 Bolts
2. AWS Dl.1 Structural Welding Code
3. PIP STS05130 Erection of Structural and Miscellaneous Steel Specification
4 S-000-3130-002 Construction Specification for Steel Structure Site Erection