Maintenance of Bridges – General Planning & procedure

Maintenance of Bridges:

The maintenance of bridges, including remedial measures, shall be framed based on the detailed inspection report, including an in-depth analysis of causes for defects, deficiencies, construction faults or other probable effects. 

• After finalizing the Bridge maintenance criteria, the maintenance team will prepare the necessary drawing for maintenance work and submit these to the higher authority for approval. 
• The maintenance team or specialized agency shall execute the job after getting approval from the concerned department.

Also, Read: Blowholes/Surface voids/Bugholes in Concrete Surface

Priorities of Maintenance:

Based on the condition assessment report, every defect shall be categorized depending on the priorities of maintenance or attention required. 

• Urgent Maintenance: Jobs marked as Urgent priority shall be attended to urgently as this may affect the full component of the structure/system as well as the project.
• Special Maintenance: That maintenance of bridges shall be taken as special attention next order of priority for which required detailed investigation and findings.
• Recurrent Maintenance: Next to special in order of priority where the defects which occur recurrently. Recurring work is periodic maintenance work like overlaying, painting, replacing etc.          
• Routine Maintenance: Defects attended routinely under the above priority category exaggerate the life of structures and maintain the whole project. 

Also, Read: Elastomeric Bridge Bearing – Advantages & Limitations

Bridge Maintenance Planning and Procedure:

To finalize the maintenance of bridges, the concerned Engineer or team will study the defects/distress in details recorded during the inspection, assess the reason for defects, check structural adequacy if any, check construction fault if any, suitable maintenance scheme etc. In general, IRC- SP 37:1991 guidelines shall be followed for the bridge’s load-carrying capacity. The detailed procedures of the bridge maintenance scheme are as follows.

• Study and Summarize the defects/ distress recorded during the inspection.
• The cause of defects should be identified.
• Prepare the priority list of the defects.
• Check the structural adequacy, if any, after studying the design calculation.
• Consultation should be taken with the experienced designer/agency if required.
• Check construction inadequacy, if any.
• Finalize a suitable maintenance scheme or consultant’s recommendation.
• Working drawings or sketches should be prepared for maintenance work.
• Environmental Health and Safety plans should be available.
• The authorities should approve the working methodology.
• Prepare a traffic diversion plan or blockade if required.
• Prepare a comprehensive Maintenance Report.

Also, Read: Causes, Prevention and Repair of Concrete Surface Defects

Maintenance of Bridges Criteria and Necessary Action:

On approval of the bridge maintenance scheme, the maintenance of bridges shall be executed by the maintenance team or specialized agency appointed through tender.

Maintenance for Waterway Structure:

• Abnormal scour: 
  • Recording the pattern of scouring and finding the cause of such scour. 
  • Any formation of the island to be removed.
  • Inform higher authority immediately of the remedial measure.
• Obstruction in the waterway: 
  • Obstruction to be removed completely.
• Erosion of bank, pitching:
  • Repair of pitching is essential. 
  • New/extra pitching, if required to be provided during the maintenance.

Also, Read: Rusting of Iron Rebar in Concrete – Special Repairing

Maintenance of Bridges Foundation and Substructure:

• Settlement of foundation:
  • Record the settlement and compare it with the tolerance limit.
  • Check design adequacy for excess settlement.
  • Strengthening of the existing foundation is required, if possible.
• Scour at pier location:
  • Record the pattern of scouring and find out the cause of such scour.
  • Formation of the island to be removed.
  • Inform higher authority for future course of action.
• Cracks:
  • The crack needs immediate attention to prevent further damage and deterioration of the existing structure.
  • Cementitious/epoxy-based grouting by the nozzle can be allowed.
• Damage due to the impact of vessels:
  • Damages can be repaired with the help of cementitious grouting by the nozzle.
• Spalling of concrete:
  • Chipping of local surface and removing all the loose material.
  • Replacement with high-strength cementitious grouting. 
  • It can be repaired with micro-concrete/epoxy mortar/polymer mortar depending upon the severity of the damage.
  • The surface is to be repaired by plastering.

Also, Read: Nondestructive Testing of Concrete – Methods & Guidelines

• Porous Surface/Honeycomb:
  • Surface to be cleaned, and find out the cause of leakage.
  • Epoxy-based cement grouting may be allowed by the nozzle.
  • The surface to be repaired by plastering etc.
• Exposed reinforcement and rust staining:
  • Chipping of local surface and removing loose material.
  • Application of zinc-based epoxy paint can be permitted after cleaning of reinforcement.
  • If required, additional reinforcement is to be provided by welding to make up the steel area.
  • High-strength cementitious grouting may be allowed to repair the affected area.
  • Surface to be repaired by plastering etc.
• Wet spots and Vegetation growth:
  • Wet surface to be cleaned, and find out the cause of leakage.
  • Close the leakage by epoxy-based cement grouting by nozzle or laying of waterproofing layers etc.
  • Surface to be repaired by cement mortar etc.
• Movement/deformation:
  • Record the movement within the tolerance limit, and check design adequacy for excess movement.

Also, Read: Environment Health and Safety(EHS)

Maintenance of Bridges Superstructure:

• Deflection< L/350:
  • Routine check-up of riding comfort for any unusual deflection and check condition is becoming worst, recommend load test if required.
• Deflection> L/350:
  • Strengthening by providing additional members if required.
  • Epoxy-based grouting by the nozzle.
• Cracks, Spalling of the concrete and Honeycomb:
  • Same as mentioned in the maintenance of bridges scheme for the foundation.
• Joints between segments:
  • For minor defects, it is to be repaired by grouting etc.
  • Structural adequacy to be checked for major defects.
  • Consult with the specialized agency if required.
  • As per approved methodology, if required, strengthening of external prestressing, high strength cementitious grouting, etc.
• Prestressing steel:
  • Defect in HDPC pipes: To be repaired by Tedlar tape.
  • Voids in the grout and corrosion protection in strands to be vacuum grouted are recommended by a specialized agency.
  • Excessive corrosion, loss, damage, etc., to be replaced as per the recommendation of a specialized agency.
• Anchorage:
  • Grout cap, Slip, distortion, Cracks in concrete, cracks in anchorage and corrosion to be repaired, painted, grouted or replaced as per the recommendation of a specialized agency.
• Bearing:
  • All Bearings need periodic maintenance such as Cleaning, Greasing/Oiling and Painting. 
  • A specialized agency must repair minor defects (surface cracks, tears, etc.) as per manufacturer recommendations.
  • In the case of major defects (splits between elastomer and laminates, tears, bulging, deformation, etc.) is to be replaced.
  • Replacement of bearing includes lifting the superstructure and lowering after replacement.

Also, Read: Bridge Inspection Types – Objectives and Guidelines

• Wearing Coat:
  • Potholes of any extent should be repaired by filling the same material.
  • If necessary, in the case of excessive cracking, bulging, or revealing renewal coat shall be provided.
  • Removal of existing damaged wearing coat includes sealing of crack/porous concrete over deck slab and approach slab with Epoxy mortar/Epoxy injection through nipples, if any.
• Concrete Crash Barrier/Railing:
  • Sealing of cracks should be done correctly.
  • Work includes chipping of local surface, removing loose material, cleaning of reinforcement, adding extra reinforcement if required by welding, high strength cementitious grouting, replacing the damaged railing, painting etc.
  • Existing RCC Railing shall be replaced with steel pipe railings.
  • Railings shall be repaired with a better grade of concrete/micro-concrete after applying a bond coat.
  • Barricading shall be provided to prevent any mishap.

Also, Read: Inspection of Bridges – Procedure & General Guidelines

• Expansion Joints:
  • Works including cleaning of Expansion Joints and chipping of the local surface, if required, should be done as per the guidelines.
  • Remove loose material, cleaning of reinforcement and structural steel, Adding extra reinforcement/plate by welding as required.
  • High strength cementitious/epoxy grouting, etc., as per specialized agency’s recommendation.
• Drainage Spout:
  • Choked drainage spout to be appropriately cleaned.
  • Any damage and anchor bolts to be replaced as required.
• Approach Slab:
  • Any damage should be repaired by high-strength cementitious grouting after removing the wearing course.
  • Applying a new layer as necessary or replacement wherever necessary should be done for any type of settlement.

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Summary

Article Name

Bridge Maintenance Planning and Procedure

Description

Based on the inspection report, bridge maintenance scheme including remedial measures shall be framed after a detailed inspection. The above includes in-depth analysis, cause of defects, deficiencies, construction faults or any other effects.

Author

WhiteHelmet

Publisher Name

Construction Civil

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