Manual for Highway Bridge Maintenance Inspection

IRC SP 18: Scope Summary & Key Specifications

IRC SP 18 deals with bridge inspection and reporting. The scope includes detailed documentation of all bridge components for maintenance and safety evaluation.

Key Elements Covered:

• General Info:

  • Bridge name, location, river, highway number
  • Bench mark with GTS level

• Bridge Geometry:

  • Number of spans, span lengths, angle of crossing
  • Total bridge length

• Hydraulic Data:

  • Drainage area, design discharge, design high flood level (HFL)
  • Low water level (LWL), max flow depth & velocity
  • Safe scour depths for piers and abutments

• Loadings:

  • Design live load or rated capacity
  • Special forces considered

• Soil & Foundation:

  • Founding strata details
  • Cross-section of bed strata (major bridges)

• Structural Components:

  • Foundations: type, depth, settlements, scour
  • Substructure: type (PSC, RCC, masonry), pier & abutment dimensions
  • Bearings: type and details
  • Superstructure: type, prestressing, wearing coat, expansion joints, articulation
  • Protective works: type, dimensions, layout

• Inspection Specifics:

  • Condition of joints, splices, bolts, rivets, welds
  • Suspension bridges: cables, suspenders, steel, painting, oscillations
  • Expansion joints: functioning, sealing, locking, debris, rattling
  • Wearing coat: cracks, spalling, potholes

Typical Table Extract: Bridge Report Proforma

Status of Inspecting Staff - IRC SP 18 (Clause 4.2)

Key Points:

• Inspecting Officer's Role: Responsible for thorough inspection of bridges/structures as per IRC guidelines.
• Inspection Frequency: Defined based on bridge type, age, and traffic; ensures timely detection of defects.
• Reporting: Officers must prepare detailed inspection reports using the prescribed proforma.

Inspection Report Proforma Highlights (Table 4.4)

Summary

• Inspecting officers must be qualified and authorized.
• Follow the detailed checklist to ensure structural safety.
• Use the proforma for consistent, comprehensive reporting.
• Frequency and depth of inspection depend on bridge criticality and condition.

flowchart TD
    A[Inspecting Officer] --> B[Conduct Inspection]
    B --> C[Check Structural Components]
    C --> D[Record Observations in Proforma]
    D --> E[Submit Inspection Report]
    E --> F[Follow-up Actions]

For detailed inspection intervals and qualifications, refer to IRC SP 18 Clause 4.2 and associated tables.

IRC SP 18: Periodicity of Inspection - Key Points

While IRC SP 18 does not explicitly tabulate periodicity, the following guidelines from clauses 4.1 and 4.2 apply:

• Time of Inspection (4.1):
  Inspections should be scheduled based on the bridge type, traffic, and environmental conditions. Typically, routine inspections occur every 6 months to 1 year.

• Frequency of Inspection (4.2):

  • Routine Inspection: Every 6 months to 1 year
  • Detailed Inspection: Every 3 to 5 years
  • Special Inspection: After extreme events (earthquake, flood, accidents)

• Status of Inspecting Officer:
  Must be a qualified engineer experienced in bridge inspection.

• Date of Last Inspection:
  Always record to track inspection intervals.

Typical Inspection Frequency Table (Recommended)

graph TD
A[Bridge Structure] --> B[Routine Inspection (6-12 months)]
A --> C[Detailed Inspection (3-5 years)]
A --> D[Special Inspection (Post-event)]

Note: Adjust frequency based on bridge condition, traffic load, and environmental exposure.

IRC SP 18: Records to be Maintained for Bridges

Key Specifications:

• Bridge Register (Appendix I): A master record containing data of multiple bridges.
• Reports per Bridge:
  • Original Bridge Report (detailed structural data)
  • Inspection Report (condition and maintenance status)

Original Bridge Report Includes:

Inspection Report Covers:

Maintenance & Usage:

• Reports must be clear, concise, unambiguous.
• Maintained by Works Division for easy access by inspecting officers.

flowchart LR
    A[Bridge Register] --> B[Original Bridge Report]
    A --> C[Inspection Report]
    B --> D[Foundations, Sub-structure, Bearings, Superstructure, Protective Works, Utilities]
    C --> E[Wear, Drainage, Handrails, Footpaths, Utilities, Painting]

This structured approach ensures comprehensive documentation and effective bridge management per IRC SP 18.

IRC SP 18: Key Items to be Inspected (Inspection Report Proforma)

The inspection checklist covers critical bridge components for condition assessment:

Note: This list ensures comprehensive structural and functional integrity checks.

flowchart TD
    A[Inspection Report] --> B[Wear & Thickness]
    A --> C[Drainage Spouts]
    A --> D[Handrails]
    A --> E[Footpaths]
    A --> F[Utilities]
    A --> G[Bridge Number & Painting]

Use this checklist for systematic bridge inspection and maintenance planning.

Inspection of Bearings as per IRC SP 18

IRC SP 18 provides guidance on bearing inspection focusing on:

Key Inspection Aspects:

• Type of Bearings: Metallic, elastomeric, etc.
• Design Load & Dimensions: Confirm against design specs.
• Location of Lifting Points & Lifting Procedure: For safe handling during replacement.
• Replacement History: Date and procedure.
• Maintenance Records: Last greasing date for metallic bearings.

Inspection Frequency:

• During temperature extremes.
• After floods or earthquakes.
• After unusual events: excessive traffic, battering, etc.

Metallic Bearings:

• Check for wear, corrosion, lubrication status.
• Ensure greasing intervals are followed.
• Look for misalignment or damage.

Elastomeric Bearings:

• Inspect for cracks, deformation, aging.
• Check bonding between layers.
• Confirm no excessive compression or shear.

Typical Inspection Checklist (Summary Table):

flowchart TD
    A[Start Inspection] --> B{Bearing Type?}
    B -->|Metallic| C[Check wear, corrosion, lubrication]
    B -->|Elastomeric| D[Check cracks, deformation, bonding]
    C --> E[Verify greasing date & procedure]
    D --> E
    E --> F{Unusual Event?}
    F -->|Yes| G[Detailed Inspection]
    F -->|No| H[Routine Inspection]
    G --> I[Report & Maintenance]
    H --> I

This ensures safe, reliable bearing performance in bridges and structures.

Inspection of Foundations and Scour per IRC SP 18

Key Points for Inspection:

• Foundation Type & Details:

  • Identify type: Well, Open, Piles (RCC/PCC).
  • Record dimensions: well diameter, steining thickness, pile diameter & spacing, open foundation size.

• Scour Measurement:

  • Inspect during high floods to measure maximum scour depth.
  • Use soundings around foundations; for deep wells, take regular interval soundings during flood.
  • If sophisticated methods unavailable, use weight on wire gauging.
  • Special focus on rock foundations with scouring overburden.

• Post-Flood Inspection:

  • Check for cracking, disintegration, decay, erosion, cavitation.
  • Inspect damage from floating bodies or boulders.
  • Note if water presence prevents inspection.

• Reporting:

  • Compare observed scour with design scour values.
  • Report any abnormal scour or settlement.
  • Record condition of slope pitching, aprons, toe walls, floor protection.
  • Report on reserve stone material and waterway obstructions.

Typical Scour Depth Check Formula (Conceptual)

[ D_{scour, observed} \leq D_{scour, design} ]

• If (D_{scour, observed} > D_{scour, design}), foundation stability is endangered → remedial action required.

Inspection Report Checklist (Excerpt)

flowchart TD
    A[Start Inspection] --> B{During Flood?}
    B -- Yes --> C[Measure Scour Depth by Soundings]
    B -- No --> D[Post-Flood Visual Inspection]
    C --> E{Scour > Design?}
    E -- Yes --> F[Recommend Remedial Measures]
    E -- No --> G[Record & Monitor]
    D --> H[Check Cracks,

Inspection of Structural Members (IRC SP 18)

Key points for inspection reports:

General Inspection Items

• Decay, wear & tear, structural defects needing immediate replacement.
• Condition of joints, splices, bolts, rivets, welds (looseness, damage).
• Check for excessive sag, deflection, camber loss, buckling.
• Report corrosion and paint condition on steel members.
• Check alignment and perceptible vibrations.

Suspension Bridges Specifics

• Condition of cables, suspenders, connectors.
• Structural steel condition and painting.
• Excessive oscillations (may require guy ropes).
• Condition of anchors, towers, saddles (verticality, lateral support).

Expansion Joints

• Functioning and cracks near joints.
• Condition of sealing materials (neoprene: splitting, oxidation; bitumen: hardening, cracking).
• Secureness and locking of joints.
• Check for debris and rattling.

Wearing Coat (Concrete/Bitumen)

• Surface condition: cracks, spalling, potholes, disintegration.

Proforma Highlights (Sample)

Additional Tips

• Measure deflection at consistent points each inspection.
• Sketch and document crack locations and patterns.
• Check drainage holes for blockage.

flowchart TD
    A[Start Inspection] --> B{Member Type?}
    B -->|Steel| C[Check paint, corrosion, joints, deflection]
    B -->|Masonry| D[Check joints, cracks, drainage, vegetation]
    B -->|Timber| E[Check paint, decay, defects]
    B -->|Suspension Bridge| F[Check cables, suspenders,

IRC SP 18: Inspection of Expansion Joints – Key Points

Though IRC SP 18 does not provide explicit formulas or tables, the inspection of expansion joints typically includes checking:

• Visual Condition: Look for cracks, corrosion, deformation, or leakage.
• Movement Capability: Verify the joint allows designed thermal expansion/contraction.
• Seal Integrity: Ensure seals/gaskets are intact and watertight.
• Alignment: Check for proper alignment and no undue stress on adjoining members.
• Fixings: Inspect bolts, anchors, and other fasteners for tightness and corrosion.
• Drainage: Confirm no water accumulation around the joint.

General Specifications (per good engineering practice):

Formula for Thermal Movement:

[ \Delta L = \alpha \times L \times \Delta T ]

• (\Delta L) = thermal expansion (mm)
• (\alpha) = coefficient of thermal expansion (e.g., steel ~12 × 10⁻⁶ /°C)
• (L) = length of member (mm)
• (\Delta T) = temperature change (°C)

flowchart TD
    A[Start Inspection] --> B{Visual Check}
    B -->|Cracks/Corrosion| C[Report Defects]
    B -->|No Defects| D[Check Movement]
    D -->|Movement OK| E[Check Seal]
    D -->|Movement Restricted| C
    E -->|Seal Intact| F[Check Fixings]
    E -->|Seal Damaged| C
    F -->|Fixings OK| G[Complete Inspection]
    F -->|Fixings Loose/Damaged| C

Summary: Inspect expansion joints for physical damage, movement allowance, sealing, and fixings. Use thermal expansion formula to verify design adequacy. Report any deviations promptly.

Inspection of Wearing Coat and Riding Quality (IRC SP 18)

Though IRC SP 18 lacks explicit clauses, standard practice for inspecting wearing coats includes:

Key Inspection Points:

• Thickness Measurement: Use a thickness gauge to measure the existing wearing coat thickness at multiple points.
• Tell-tale Rings: Embedded rings or markers in the wearing coat help detect wear depth.
• Visual Inspection: Check for cracks, potholes, bleeding, or stripping.
• Riding Quality: Evaluate smoothness and texture for user comfort and safety.

Typical Specifications:

Formula for Thickness Loss:

[ \text{Thickness Loss} = \text{Designed Thickness} - \text{Measured Thickness} ]

If thickness loss exceeds allowable limits, resurfacing or maintenance is recommended.

flowchart LR
    A[Start Inspection] --> B[Measure Thickness]
    B --> C{Thickness ≥ 75%?}
    C -- Yes --> D[Check Riding Quality]
    C -- No --> E[Plan Maintenance]
    D --> F[Report Findings]
    E --> F

Summary: Use tell-tale rings and thickness gauges, compare with design thickness, and assess riding quality for maintenance decisions.

Inspection of Drainage and Protective Works — IRC SP 18

Key Inspection Items & Reporting (from Table 4.4):

• Slope Pitching, Apron, Toe Walls:

  • Check slope angle, thickness, width of pitching.
  • Inspect for erosion, cracks, disintegration.

• Floor Protection Works:

  • Condition of impervious floors, flexible aprons, curtain walls.
  • Note any damage or deterioration.

• Scour:

  • Measure extent and location of scour.
  • Compare with design scour depths to identify abnormal conditions.

• Waterway:

  • Check for obstructions, undergrowth.
  • Report flow pattern changes, maximum flood levels (mark on piers/abutments).
  • Assess adequacy of waterway and any abnormal afflux.

• Foundations:

  • Note settlement, cracking, erosion, cavitation.
  • Check damage from floating debris or boulders.
  • For subways, inspect seepage and foundation damage.

• Substructure Drainage:

  • Check backfill drainage behind abutments.
  • Verify weep holes functionality and moisture presence.

Specifications to Record:

• Height, slope, thickness of slope pitching and apron.
• Details of protective works (guide bunds, spurs).
• Reserve stone material quantity (check against specified).

Typical Scour Depth Check Formula:

[ d_s = K \times V^2 / (2g) ]

• (d_s) = scour depth
• (V) = flow velocity
• (g) = acceleration due to gravity
• (K) = empirical coefficient depending on soil type

Summary Flow for Inspection Reporting:

flowchart TD
    A[Start Inspection] --> B{Check Slope Pitching}
    B -->|Damage| C[Record Damage & Dimensions]
    B -->|No Damage| D[Check Floor Protection]
    D -->|Damage| E[Record Damage]
    D -->|No Damage| F[Measure Scour]
    F --> G[Compare with Design Scour]
    G --> H{Scour Abnormal?}
    H -->|Yes| I[Report & Recommend Action]
    H -->|No| J[Check Waterway & Obstructions]
    J --> K[Check Foundations & Substructure]
    K --> L[

Inspection of Utilities and Ancillary Facilities (IRC SP 18)

Key points for inspection and reporting utilities and ancillary facilities on bridges:

Utilities Inspection Checklist

• Water & Sewage Pipes:
  • Check for leakage and report.
• Telephone & Electric Cables:
  • Inspect for damage or interference.
• Lighting Facilities:
  • Assess condition and functionality.
• Other Utilities:
  • Report any damages caused by or to utilities.

Ancillary Facilities

• Drainage Spouts:
  • Check clogging, deterioration, damage.
  • Verify projection affecting structural members.
  • Report adequacy of drainage.
  • For subways, check pumping arrangements.
• Handrails:
  • Inspect general condition, expansion gaps, missing parts.
  • Check for collision damage and alignment.
• Footpaths:
  • Report damage (e.g., vehicle mounting).
  • Note missing slabs.

Reporting Format (Proforma)

Include:

• Date and signature of inspector.
• Bridge number.
• Condition of painting.
• Position and condition of surface utilities (telephone cables, electric lines, water vents, sewage).
• Details of foundations, substructure, bearings, superstructure, protective works, and special features.

Summary Table: Utilities Inspection

flowchart TD
    A[Start Inspection] --> B{Utilities?}
    B -->|Water/Sewage Pipes| C[Check leakage & thickness]
    B -->|Telephone/Electric| D[Inspect damage]
    B -->|Lighting| E[Check condition]
    B -->|Drainage Spouts| F[Check clogging & projection]
    B -->|Handrails| G[Inspect condition & alignment]
    B -->|Foot

Special Considerations for Suspension Bridges (IRC SP 18)

Key Inspection & Maintenance Points:

• Main Suspension Cables: Check protective coatings for soundness to prevent corrosion.
• Cable Bands: Ensure cable bands holding suspenders are secure and undamaged.
• Saddles and Anchorages: Inspect for corrosion, wear, and structural integrity, especially at tower locations.

Inspection Reporting (From Table 4.4 Proforma):

• Foundations: Type (Well, Open, Piles), material (RCC, PCC), depth, settlement/scour.
• Sub-structure: Type (PSC, RCC, masonry), pier & abutment dimensions.
• Bearings: Type and details.
• Superstructure: Type, prestressing details, expansion joints, articulation.
• Protective Works: Guide bunds, abutment protection with sketches and dimensions.
• Utilities: Position of surface utilities on the bridge.

Additional Notes:

• Regular inspection intervals are crucial for corrosion-prone elements.
• Protective coatings and cathodic protection methods are recommended for cables.
• Monitoring cable tension and elongation can help predict maintenance needs.

flowchart TD
    A[Inspection of Suspension Bridge] --> B[Check Main Suspension Cables]
    A --> C[Inspect Cable Bands]
    A --> D[Examine Saddles & Anchorages]
    A --> E[Report Foundation & Substructure Details]
    A --> F[Check Bearings & Superstructure]
    A --> G[Review Protective Works & Utilities]

For detailed design and load considerations, refer to IRC:6 and IRC:112 for suspension bridge loadings and cable design formulas.

IRC SP 18: Reporting and Follow-up Actions on Bridge Inspection

Key Specifications & Proforma Elements:

1. Bridge Identification

• Name/No. of Bridge, River Name
• Highway Name/No., Bridge Location
• Benchmark Location with G.T.S. level

2. Span Details

• Number of spans (center-to-center of piers)
• Total bridge length
• Angle of crossing

3. Hydraulic Particulars

• Drainage area (sq. km)
• Design discharge (m³/s)
• Design High Flood Level (HFL)
• Vertical clearance (m)
• Low Water Level (LWL)
• Maximum depth & velocity of flow
• Ordinary flood level
• Safe scour depths for piers and abutments

4. Loadings

• Design live load or rated capacity
• Special forces considered (e.g., seismic, wind)

5. Soil Particulars

• Founding strata description
• Cross-section of river bed strata (major bridges)

Follow-up Action on Inspection Report (Key Items)

Summary Flow for Reporting & Follow-up

flowchart TD
    A[Inspection] --> B[Record Observations]
    B --> C[Fill Proforma Sections]
    C --> D[Identify Deficiencies]
    D --> E[Recommend Follow-up Actions]
    E --> F[Schedule Repairs/Maintenance]
    F --> G[Re-inspection & Closure]

Note: Use this structured proforma and checklist to ensure comprehensive inspection reporting and timely follow-up on bridge maintenance.

IRC SP 18: Proforma for Inspection Reports (Clause 4.3)

While IRC SP 18 does not provide a fixed proforma, typical inspection reports for road/bridge works include:

Key Components of Inspection Report Proforma

• Project Details: Name, location, contract no., date
• Inspection Details: Date & time, inspector’s name, weather conditions
• Work Description: Activity inspected (e.g., concrete pouring, reinforcement placement)
• Material Details: Source, batch no., test results (strength, slump, etc.)
• Measurements: Dimensions checked vs. design (e.g., thickness, cover)
• Observations: Compliance with specifications, defects, deviations
• Photographs: Visual evidence of work status
• Recommendations: Corrective actions, approvals or rejections
• Signatures: Inspector, contractor, client representatives

Example Table for Concrete Inspection

This format ensures systematic documentation and traceability during construction inspection.