Class
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Diagnostic
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Scope of Work
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1. Routine Maintenance
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No significant defect & no replacement or repair of any element of
the bridge is required. The work involves routine activities to be
conducted in a cyclic manner. RM is defined as the servicing of a
bridge structure
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- Removal of
debris(soil, aggregate, cow dung and or any foreign material) from
deck, footpath, railings, bearing, expansion joints;
- Cleaning and lubrication of bearing; and
- Removal of grass, bushes from bridge surfaces, wing and or abutment wall, bearing area approach road
- Cleaning of drainage spout on the deck
- Drain
out the accumulated water in the chambers, cleaning and re-greasing of
main and hanger cables for suspension bridge and check the abnormal
vibration of stay –cable for cable-stayed bridge.
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2. Minor Maintenance
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Damages detected are very minor and do not require any design input to carry out the treatment or rectify the defects.
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- Rectification and replacement of bridge expansion joints, railing posts, safety barriers, sign board;
- Rectification damages of approach slabs, ballast walls etc.
- Minor
bed protection to minimize scour required to keep the foundations
unexposed, bank protection in order to prevent breaching of approach
road;
- Tightening of loose bolts/ U-hooks, replacement of
missing knot bolts in the steel members, spot re-painting work of steel
members of suspension as well as cable-stayed bridge. Reporting to DRO
office in case of abnormal vibration of cable system during wind.
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3. Major Maintenance
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- Numerous defects of structural and hydraulic significance which may soon prevent the bridge in its proper functioning.
- Detailed investigation may be required to design the maintenance work (e.g. non-destructive testing)
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- All or some of the minor maintenance work scope plus
- Major repair/replacement of slabs/ railings, bearings, piers
- Painting and replacement of steel members
- Greasing,
covering of cables, changing of deck material and tightening or
replacing bolts, inspection of anchoring system etc of suspension
/cable-stayed bridge
- Bed and or bank protection works (River training works) costing more than 0.3 million rupees
- Major maintenance of decking system and re-painting of steel members
- Seeking
expert advice for major maintenance of anchorage system, main
cable/hanger, cable/suspension devices/saddles for suspension bridges
and also stay-cable pylon/tower and anchoring devices at pylon as well
as at deck for cable-stayed bridges
- Jacketing of pier columns
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4. Emergency Maintenance
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- One
or more elements of the bridge is heavily and critically damaged that
compromises the safety of the traffic using the bridge;
- Emergency repair of one or more parts are required followed by major maintenance of the bridge;
- Load restriction and traffic safety signs need to be put in place
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- All or some of the minor maintenance work scope plus
- Major repair/replacement of slabs; and/or
- Major repair/replacement of railings
- Major repair/replacement of piers; and/or
- Repair rehabilitation or new construction of check dam when the bridge is at risk from scour
- Remedial measures as advised by experts after investigations shown in scope of works for Major Maintenance.
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