Handbook for Bridge Inspections - TSP2

Procedures
Scope
Sag is measured using cord or possibly piano wire as indicated in
Figure 7.2-3. A bob should be hung on the end of the cord; alternati
vely a spring balance may be used. The vertical distance bctween
the central suspension rod and the taut cord (the amount of sag) is
then measured. The procedure is repeated for all suspension rods 0
n both sides o f the bridge. The amount of sag is nonnally the same
over the whole bridge, but can vary somewhat near the towers
because ofthe di stance between the fi nal suspension rod and the
tower, and the tension of the braces. It is important that the bridge
is not subject to traffic loads or lift during measuring.
Acceptance Inspection
Sag should normally be measured in conjunction with the bridge's
construction . However, iflhis cannol be shown 10 be documented,
then these measurements should be taken during the Acceptance
Inspection.
Main Cable Inspection - Special Inspection
The need to take these measurements should be evaluated during
the visual inspection.
Equipment
Purpose
Procedures
Scope
• Cord, possibly piano wire
• Plumb line, possibly a spring balance
• Folding rule
7.2.7 Recording Bridge Details
To record:
• mi ss ing data co ncerning elements, element types, size etc.
• marking a bridge
• erecting traffic signs
• bridge drawings (completed drawings)
• archi ve/computer system data
Procedures and eq uipment requirements wi ll vary according to the
task in hand.
Acceptance Inspection
Should data for new bridges not have been recorded at the building
stage, then this should be done at the latest during the Completion
Survey.
Major Inspection - Special Inspection
The data in BRUTUS should be checked for accuracy. Additional
inspections should be carried out after reconstruction or reinforcement
works.
Equipment
• Trip counter
• Bridge traffic sign and tools for erecting it
• Fo ld ing rule
• Measuring tape
• Camera
• Surveying equipment