Guidelines for Fabrication and Erection of Steel Bridges

Fabrication Key Points from IRC SP 104 (2015):

1. Base Metal & Joint Preparation (Clause 1.10 - 1.15)

• Base metal preparation: Clean, free from rust/oil.
• Joint design: Provide sketches showing parts arrangement, welding groove details, weld passes, and sequence.
• Joint preparation: Proper beveling, fit-up, and alignment.
• Welder qualification: As per relevant IS standards.
• Welding parameters: Controlled for quality and strength.

2. Welding Parameters Table (Clause 1.15 & 2.12)

Parameters must be optimized per weld pass for quality.

3. Post-Weld Treatment (Clause 1.20)

• Preheating and interpass temperature: As per steel grade.
• Peening: To reduce residual stresses.
• Post weld treatment: Stress relieving, if required.
• Rectification of defects: Grinding, rewelding.
• Inspection: Visual, radiographic, ultrasonic as applicable.

4. Materials & Standards (Clause 1.2)

• Use steel complying with relevant IS codes such as:
  • IS 2062 (Structural steel)
  • IS 808 (Dimensions for rolled sections)
  • IS 1239 (Steel tubes)
  • IS 1852 (Tolerances)
  • IS 1030, IS 2644 (Castings and forgings)

Summary Diagram for Welding Process

flowchart TD
    A[Base Metal Preparation] --> B[Joint Design & Preparation]
    B --> C[Welder Qualification]
    C -->

IRC SP 104 - General: Key Formulas, Tables & Specifications

1.2 Materials and Properties

• Structural steel must comply with IS standards (e.g., IS 808, IS 2062, IS 4923).
• Material properties are nominal values as per relevant IS codes.
• Steel types include hot rolled sections, tubes, plates, bars, castings, and forgings.

Important IS Codes for Steel:

Welding Parameters (Typical for Welded Plate Girders):

General Fabrication Specifications:

• Follow IS codes for dimensions, tolerances (IS 1852), and material control.
• Welding must adhere to qualified procedures and parameters.
• Use approved steels for structural members; machining steels require specific approval.

flowchart LR
    A[Material Selection] --> B[IS Standards Compliance]
    B --> C[Fabrication: Cutting, Bending, Welding]
    C --> D[Quality Assurance & Inspection]
    D --> E[Erection & Assembly]

Summary: Use IS codes for material specs, welding parameters as per tables, and maintain quality per IRC SP 104 clauses 1.2 & 1.10 for successful steel fabrication and erection.

IRC SP 104 - Clause 1.2: Material and Properties Summary

Structural Steel:
Must comply with relevant IS codes, including but not limited to:

Casting and Forgings:
Must comply with:

Bolts, Nuts, Rivets:
Relevant IS standards include IS 1148, IS 1149, IS 1363, IS 1364, IS 1367, IS 1929, IS 2155, IS 3640.

Key Testing & Repair Specifications (Clause 1.16.2)

• Mechanical & chemical tests per IS 2062.
• Ultrasonic testing mandatory for plates ≥ 25 mm thick.
• Rolling/cutting tolerance per IS 1852.
• Edge discontinuities repair per Table 5:

IRC SP 104: Material Control (Clause 1.3) - Key Points & Specifications

Material Specification:

• Structural steel must conform to IS 2062 or as specified in drawings.
• Steel sections must have Mill Test Certificates (MTC) indicating compliance.
• Cast/heat mark numbers and plate numbers must be recorded before fabrication.

Testing & Quality Assurance:

• Sample test pieces from each cast mark sent to an independent test house approved by the engineer.
• Fabrication only after correlation of MTC and test house reports.
• Engineer's approval required for any steel not meeting above quality.
• Identification as per Quality Assurance Plan (QAP).
• Inspection quantum and sample size agreed with the engineer.
• Hard stamping for mark transfer only in engineer-approved areas.

Material Properties & Relevant IS Codes (Clause 1.2)

Summary Table: Material Control Workflow

flow

Storage and Handling of Materials as per IRC SP 104

Key Specifications (Clause 1.4 & 2.1.3)

• Raw steel: Store above ground, free from dirt, corrosion, and distortion. Use platforms, skids, or supports with slight floor slope for drainage.
• Fabricated components: Stack neatly above ground with visible match marks; avoid deformation.
• Electrodes: Store in dry, warm conditions in racks by specification.
• Fasteners (bolts, nuts, washers): Store above ground in gunny bags with protective oil coating.
• Paint: Store under cover in airtight containers.
• Handling: Use lifting beams with proper slings to minimize damage/distortion.

Site Storage (Clause 2.1.3)

• Storage area near site, level, firm, and free from waterlogging.
• Access roads and stacking areas must allow crane movement.
• Provide racks, sleeper stands, and open spaces for storage.
• Ensure visibility of erection marks and accessibility for handling equipment.
• Small tools stored in covered containers.

Safety & Standards

• Equipment safety: IS 7293
• Storage safety: IS 7969
• Refer Appendix-K for cranes.

Summary Table

flowchart LR
    A[Raw Steel] --> B[Platforms/Skids]
    B --> C[Above Ground Storage]
    C --> D[Drainage Floor with Slope]
    E[Fabricated Components] --> F[Stack Neatly]
    F --> G[Visible Match Marks]
    H[Electrodes] --> I[Dry, Warm Racks]
    J[Fasteners] --> K[Oiled, Gunny Bags]
    L[Paint] --> M[Airtight Containers]

This ensures materials remain undamaged and ready for erection.

Workmanship and Quality Assurance Plan (QAP) - IRC SP 104

Key Specifications (Clause 1.5 & related):

• QAP Preparation: Tailored to fabrication nature; details nodal inspection points at various fabrication stages.
• Approval: QAP must be approved by the Engineer before fabrication starts.
• Marking: All components must carry a mark number and serial number for traceability; marking method must ensure identity retention throughout fabrication.
• Fabrication Compliance: As per Engineer’s drawings and relevant IS codes.
• Personnel: Qualified personnel only.
• Handling & Storage: Raw, in-process, and finished materials must be properly stored and identifiable.
• Stage Inspection: Mandatory at critical points to ensure quality.
• Joining Methods: Welding, bolting, riveting as per IS codes or Engineer-approved QAP.

Welding Specifics (Clause 1.20):

Summary Table: Special Fabrication Tolerances for Welded Plate Girders (Indicative)

Recommended QAP Flowchart

flowchart TD
    A[Prepare QAP] --> B[Submit to Engineer]
    B --> C{Engineer Approval?}
    C -- Yes --> D[Start Fabrication]
    C -- No --> A
    D --> E[Mark Components]
    E --> F[Stage Inspections]
    F --> G[Final Inspection]
    G --> H[Fabrication Completion]

References:

• IS Codes for welding and fabrication (e.g., IS 816, IS 9595)
• IRC SP 104 Clause 1.5 & 1.

IRC SP 104 - Straightening and Flattening (Clause 1.6)

• Purpose: Remove deformation/distortion in steel plates and structural sections from rolling or handling.
• Methods:
  • Structural sections: Preferably straightened by hydraulic presses.
  • Plates: Flattened by presses or roller straighteners.
• Pressure: Applied force must not injure the material.
• Prohibited: Hammering is not allowed.
• Heat Application: For deformation due to handling, heat or mechanical force can be used.
  • Max heating temperature: 650℃
  • Heating and cooling rates must be pre-determined and approved by the engineer.

Key Specifications Summary

Process Flow (Mermaid.js)

flowchart TD
    A[Deformed Steel Plate/Section] --> B{Type?}
    B -->|Structural Section| C[Hydraulic Press Straightening]
    B -->|Plate| D[Press or Roller Straightening]
    C --> E{Deformation due to Handling?}
    D --> E
    E -->|Yes| F[Apply Controlled Heat (≤650℃) + Mechanical Force]
    E -->|No| G[No Heat Required]
    F --> H[Check for Material Damage]
    G --> H
    H --> I[Approved Flat & Straight Material]

Note: Always consult the engineer before heat application and ensure no damage occurs during straightening.

IRC SP 104: Layout for Camber - Key Points

1. Full Scale Layout (Clause 1.7)

• Layout done on a leveled bed as per nominal length drawings.
• Jigs for gussets and members made from nominal layout.
• Hole positions & angles per nominal layout.
• Member lengths manufactured from the camber diagram.
• Ends machined for proper joint contact.

2. Measurement of Camber (Clause 1.16.3)

• Measure camber after welding, heating, and cooling.
• Horizontal curvature checked vertically by offsets from string line or equivalent.
• Camber checked by engineer-specified method.

3. Cambering During Erection (Clause 2.2.7)

• Joints drifted, bolted, riveted to geometric outline.
• Members elastically strained to align holes.
• Use camber jacks spaced at panel points and ends.
• Bottom chord placed on jacks, leveled, joints riveted.
• Vertical/diagonal members installed with temporary gussets adjusted for camber.
• Panel points lowered to produce camber.
• Top chord erected symmetrically from center.
• Temporary gussets replaced by permanent gussets.
• End posts erected last.

Summary Table: Camber Layout & Erection Steps

flowchart TD
    A[Nominal Layout on Leveled Bed] --> B[Make Jigs for Gussets & Members]
    B --> C[Manufacture Members as per Camber Diagram]
    C --> D[Place Bottom Chord on Camber Jacks]
   

IRC SP 104 - Key Points on Bending of Steel Plates

1. Cold Bending (Clause 1.8.1)

• Not allowed for steel with yield stress ≥ 360 MPa.
• Bend line should be perpendicular to rolling direction.
• Avoid plates with kinks, cracks, dents, or necking.
• Use largest permissible bend radius.
• Inspect load points visually and via magnetic particle testing.

2. Heating and Bending (Clause 1.8.2)

• Heating must be done before painting.
• Pre-load stresses limited to 0.5 × yield strength (f).
• Use neutral flame with orifice size proportional to plate thickness.
• Heating temperature max 650°C, measured within 5-10 sec after flame removal.
• Avoid overheating and buckling; cool steel below 315°C before compressed air cooling.
• No water/mist cooling allowed.
• Allow cooling below 120°C before reheating.

3. Welding (Clause 512.4.4)

• Follow IS 816 / IS 9595 standards.
• Weld Procedure Specifications (WPS) must be approved.
• Welders must be qualified per relevant IS codes.
• Non-Destructive Testing (NDT) as per designer’s directives.

Bend Radius Guideline (General Engineering Practice)

Summary Diagram: Bending Process Flow

flowchart TD
    A[Plate Selection] --> B{Yield Stress < 360 MPa?}
    B -- No --> C[No Cold Bending Allowed]
    B -- Yes --> D[Cold Bending with Largest Radius]
    D --> E[Visual & Magnetic Particle Inspection]
    C --> F[Heating & Bending]
    F --> G[Apply Pre-load ≤ 0.5 × f_y]
    G --> H[Heat with Neutral Flame (≤ 650°C)]
    H --> I[Cool below 315°C before compressed air]
    I --> J[Allow cooling below 120°C before

IRC SP 104: Cutting and Edge Preparation (Clauses 1.9 & 1.10)

Key Methods for Cutting & Edge Preparation:

• Shearing: Preferred for plates; cut full length in one pass.
• Cropping, Sawing, Flame Cutting: Acceptable alternatives.
• Grinding: Sheared edges must be ground smooth, especially for secondary use (stiffeners/gussets).
  • Contact gap tolerance: ≤ 0.2 mm over 60% of contact area for stiffeners.

Planing and Machining:

• Thickness allowance before finishing:
  • Plates/sections ≤ 12 mm: cut 3 mm oversize.
  • Plates/sections > 12 mm: cut 6 mm oversize.
• Post-fabrication:
  • Butt ends must be smoothened (end milling).
  • Machined faces on compression members must be perpendicular to member axis.
  • Uniform contact with tolerance of 0.4 mm allowed at isolated points.

Summary Table: Cutting Allowances

Important Notes:

• Grinding ensures proper fit and load transfer.
• Machining ensures dimensional accuracy and perpendicularity.
• Inspecting Officer may allow minor tolerance deviations.

flowchart LR
    A[Start: Plate/Section] --> B{Thickness ≤ 12 mm?}
    B -- Yes --> C[Cut 3 mm oversize]
    B -- No --> D[Cut 6 mm oversize]
    C & D --> E[Fabrication]
    E --> F[End milling of butting ends]
    F --> G{Compression member?}
    G -- Yes --> H[Machined faces ⟂ axis]
    G -- No --> I[Standard finishing]
    H & I --> J[Final inspection with tolerance ±0.4 mm]

For detailed fabrication, always follow the specified drawing instructions and engineer’s directions.

IRC SP 104: Clause 1.10 — Planing and Machining

• Machining Requirements:

  • Plates/sections ≤ 12 mm thick: Cut to 3 mm or more oversize for finishing.
  • Plates/sections > 12 mm thick: Cut to 6 mm or more oversize.
  • After fabrication, butting ends must be smoothened by end milling to ensure uniform contact.

• Compression Members:

  • Machined faces must be perpendicular to member axis.
  • Contact surfaces as specified in drawings.

• Tolerance:

  • Inspecting Officer may allow 0.4 mm tolerance at isolated points on butting lines.

Summary Table for Cutting Oversize

Key Notes:

• Machining ensures accurate fit-up and uniform load transfer.
• End milling improves contact quality at joints.
• Follow relevant IS standards for materials (e.g., IS 808, IS 1730, IS 2062).

flowchart TD
    A[Cut Plate/Section] --> B{Thickness ≤ 12 mm?}
    B -- Yes --> C[Cut oversize by ≥ 3 mm]
    B -- No --> D[Cut oversize by ≥ 6 mm]
    C & D --> E[Fabrication]
    E --> F[End Milling of Butting Ends]
    F --> G[Check Machined Face Perpendicularity]
    G --> H[Ensure Proper Contact & Tolerance ≤ 0.4 mm]

This ensures precise fabrication and assembly as per IRC SP 104.

Key Specifications for Rivet and Bolt Holes (IRC SP 104, Clause 1.11 & 1.16.4):

• Hole Diameter:

  • For bolts/rivets ≤ 25 mm Ø: Hole diameter = Bolt diameter + 1.5 mm
  • For bolts/rivets > 25 mm Ø: Hole diameter = Bolt diameter + 2.0 mm

• Hole Making Method:

  • Drilled holes: Mandatory for main load-carrying members.
  • Punched holes: Allowed for secondary members (floor plates, handrails) and materials with:
    • Yield stress, f ≤ 360 MPa
    • Thickness ≤ (5600/f) mm

• For thick packs (Grade E250 > 20 mm or E350 > 16 mm):

  • Drill holes 3 mm smaller than required diameter
  • Ream holes after assembly to full diameter

• Close tolerance/turn-fitted bolts:

  • Hole diameter tolerance: 0 to +0.15 mm of bolt shank diameter
  • Drill through all thickness clamped together
  • Ream to final size subsequently

Hole Diameter Formula:

Punching Thickness Limit

[ t \leq \frac{5600}{f} \quad \text{(where } f \text{ is yield stress in MPa)} ]

Hole Tolerance for Close Tolerance Bolts

[ D = d + (0 \text{ to } +0.15 \text{ mm}) ]

flowchart TD
    A[Start: Bolt Diameter (d)] --> B{Is d ≤ 25 mm?}
    B -- Yes --> C[Hole Diameter = d + 1.5 mm]
    B -- No --> D[Hole Diameter = d + 2.0 mm]
    C & D --> E{Material Yield Stress ≤ 360 MPa and Thickness ≤ (5600/f)?}
    E -- Yes --> F[Punch hole allowed for secondary members]
    E -- No

Key Specifications & Formulas for Bolted Connections (IRC SP 104)

1. Surface & Washer Requirements (Clause 1.12)

• Joint surfaces must be clean, free from scale, dirt, burrs.
• Slope of bolted part surfaces ≤ 1:20; else use tapered washers.
• Washer mandatory under nut or bolt head.
• Use calibrated torque wrenches for final tightening.

2. Bolt Tightening by Nut Rotation (Table 1)

3. HSFG Bolts (Clause 1.13 & J.5, J.6)

• Surface prep: Aluminium metalizing (150 µm thick) or wire brush cleaning.
• Tightening beyond yield point to induce plastic flow.
• Bolt tension per IS:4000 (Table J.2):

Additional Notes

• For Class 10.9 bolts, two washers (head & nut) required.
• Use DTI washers as per bolt class and rotation method.
• Tighten all bolts to snug tight, then additional rotation as above.

flowchart TD
    A[Prepare Joint Surface] --> B{Slope ≤ 1:20?}
    B -- Yes --> C[Use Plain Washer]
    B -- No --> D[Use Tapered Washer]
    C & D --> E[Tighten bolts to Snug Tight

HSFG Bolted Connections - IRC SP 104 Key Points

1. Bolt Properties & Classes (IS 4000, IS 3757)

• Property Classes: 8.8 & 10.9
  • Class 8.8: Ultimate tensile strength = 800 N/mm², Yield = 640 N/mm² (80%)
  • Class 10.9: Higher strength bolts with corresponding properties.
• Marking: Bolts embossed with 8S or 10S on head.

2. Bolt Tension (Preload) - Minimum Values (from IS:4000, Table J.2)

3. Washers & DTI (Direct Tension Indicator)

• Class 10.9 bolts: Two washers (one under head, one under nut) OR one DTI + one plain washer.
• Class 8.8 bolts: One DTI washer suffices.
• If nut rotates, DTI under head; if head rotates, DTI under nut (washer-faced nut per IS:6623).

4. Surface Preparation (Clause J.5)

• Steel interfaces must be Aluminium metalized (150 µm thick) without coating.
• For existing structures, clean by wire brushing/flame cleaning.
• If no prep possible, reduce slip factor accordingly.

5. Installation & Tightening (Clause J.6)

• Tighten bolts beyond yield point to induce plastic flow → ensures proper preload.
• Preload values as above must be strictly followed.
• HSFG bolts rely on friction, not bolt shear.

flowchart TD
    A[Steel Interface] -->|Aluminium Metalized| B[HSFG Bolted Joint]
    B --> C{Bolt Class}
    C -->|8.8|

IRC SP 104 - Riveted Connection Key Points

Specifications:

• Surface Preparation: Joint surfaces must be clean, free from scale, dirt, burrs, or defects.
• Assembly: Use bolts to firmly draw members together; every 3rd hole to have assembly bolts before riveting.
• Hole Alignment: Holes in built-up members must be aligned dead-square; use assembly fixtures; drift pins only for matching holes, not distorting.
• Heating Rivets:
  • Mild steel rivets:
    • Hydraulic riveting: 650°C to 700°C (light cherry red)
    • Pneumatic riveting: orange color
  • High tensile steel rivets: up to 1100°C
• Rivet Driving: Rivet must fill hole completely; heads to standard dimensions or fill countersunk holes fully.
• Riveting Method: Hydraulic or pneumatic machines preferred; working pressure per engineer's approval.
• Defective Rivets: Must be removed without damaging members; replaced properly.
• Transportation: Unriveted parts secured with bolts.

Inspection & Testing:

• Filler Gauge Test: 0.2 mm gauge should not enter under rivet head more than 3 mm.
• Hammer Test: Rivet heads must be tight and free from vibration.
• Defects: Loose, cracked, or eccentric rivets must be cut out and replaced.

Typical Rivet Head Dimensions (IS 800 / IRC Reference)

Rivet Heating Colors:

flowchart LR
    A[Prepare joint surfaces] --> B[Align holes with assembly bolts]
    B --> C

IRC SP 104: Welded Connection (Clause 1.15) - Key Points

Types of Butt Welds (Fig. H-1)

• Open Square Butt Weld (with/without backing)
• Single & Double V, U, J Butt Welds (with/without backing)
• Single & Double Bevel Butt Welds
• Asymmetric Double V and U Butt Welds

Welding Procedure (Fig. H-2)

• First side welded
• Back gouged to clean metal
• Second side welded (for complete penetration)

Transitioning Unequal Thickness Plates (Figs. H-3 to H-6)

• Chamfer thicker/wider plate edges before welding
• Use sloping weld surfaces to reduce stress concentration
• Reinforcement size: not less than t/4 or 10 mm
• If transition not practicable, weld thickness should match thicker part

Welded T-Joint (Fig. H-7)

• Reinforcement size = t/4 and ≥ 10 mm
• Minimum run-on/off plate length = 40 mm (Fig. H-8)

Important Specifications:

Summary Diagram (Welding Sequence)

flowchart LR
    A[First Side Welded] --> B[Back Gouged to Clean Metal]
    B --> C[Second Side Welded]

For detailed weld design, refer to qualified welding procedures and ensure full penetration for critical joints.

Inspection and Testing for Fabrication and Assembly - IRC SP 104 (Clause 1.16)

Key Specifications:

• Material Testing:
  • Structural steel tested as per IS:2062 for mechanical & chemical properties.
  • Rivets, bolts, nuts, washers, welding consumables, forgings, castings, stainless steel tested per relevant IS standards.
• Tolerances:
  • Rolling & cutting as per IS:1852.
  • Thickness measurements ≥15 mm from edges.
• Ultrasonic Testing (UT):
  • Mandatory for plates ≥25 mm thickness to detect laminations.
  • Flame cut edges without visible laminations exempt unless engineer specifies.
• Surface Inspection:
  • Check for surface defects & edge laminations during fabrication & blast cleaning.
  • Report significant laminations to Engineer.

Table 5: Discontinuities for Edge Defects & Repair Procedure

Additional Notes:

• No protective coating before inspection/testing.
• Maintain Inspection Register (Appendix-A) for all fabrication stages.
• Use UT to measure imperfection depth accurately.
• Welding procedures must comply with material requirements.

flowchart TD
    A[Start Fabrication] --> B[Material Testing per IS:2062]
    B --> C[Rolling & Cutting Tolerance Check (IS:1852)]
    C --> D[Ultrasonic Testing for Plates

IRC SP 104: Bearings - Key Specifications & Tolerances

1. Roller Bearings (Appendix D)

• Diameter tolerance: ±0.04 mm from contract drawing dimension.
• Ensures precise rolling element size for smooth operation.

2. Knuckle Bearings (Appendix D)

• Interchangeable Work:
  • Pins diameter: Not greater than D, not less than D - 0.2 mm.
  • Knuckle castings bore: Greater than D but ≤ D + 0.3 mm.
• Non-Interchangeable Work:
  • Difference between pin diameter and knuckle bore ≤ 0.5 mm.
  • Each set numbered and stamped for identification.

3. Thickness of Castings (Both Types)

• No negative tolerance allowed.
• Rib edges must maintain thickness as per drawings and be parallel.

4. Positioning

• Accurate center marks on bottom slab for erection alignment.

Summary Table: Tolerances for Bearings

This ensures precision fit, interchangeability, and durability of bridge bearings per IRC SP 104:2015. For detailed fabrication and inspection, refer to Appendix D of the code.

Painting and Metallising per IRC SP 104: Clause 1.18.3 & Appendix E

Metalizing & Painting for Corrosive Environments (Coastal/Industrial/Sub-urban)

Alternative Protective Painting (Where Metallising Not Feasible)

Metallising (Appendix E)

• Surface Prep: Abrasive blasting per IS:6586, clean, dry, roughness per IS:5905 Appendix A.
• Metal Spraying: Wire method (3 or 5 mm wire diameter), minimum 2 passes, coating applied within 8 hours of blasting.
• Coating: Sprayed aluminium as protective layer before painting.

Summary Diagram: Protective Coating Layers

graph LR
A[Steel Surface] --> B[Surface Preparation: Abrasive Blasting]
B --> C[Metalising: Sprayed Aluminium Coating]
C --> D[Primer Coat: Epoxy Zinc Phosphate]
D --> E[Intermediate Coat: Zinc Chrome Primer]

IRC SP 104: Erection - Key Points & Specifications

1. Erection Scheme & Procedure (Clause 2.2)

• Approval: Erection methodology and equipment must be submitted and approved by the engineer.
• Wind Loads: Account for local wind conditions in the erection scheme.
• Ground Stability: Ensure stable ground to prevent settlement of temporary supports.
• Support During Erection: Use staging with blocks and camber jacks to maintain correct elevation, alignment, and camber.
• Protection: Use padding when chains/slings contact members to avoid dents or distortion.
• Lifting: Employ proper lifting methods for flexible members to prevent permanent deformation.
• Readiness: Begin erection only when all resources and foundations are ready.
• Mechanization: Use mechanization for large volume erection works.
• Modular Construction: Pre-assemble modules in yard and check fit before site erection.
• Difficult Terrain: Conduct trial assembly and apply simulated loads to study behavior.
• Setting Out: Supporting structures must be accurately set to lines and levels.
• Bolting: Complete erection with adequate drifts and bolts ensuring correct positioning.

2. Important Considerations

flowchart TD
    A[Prepare Erection Scheme] --> B[Engineer Approval]
    B --> C[Check Ground Stability]
    C --> D[Pre-assemble Modules in Yard]
    D --> E[Transport to Site]
    E --> F[Set Out Supports & Levels]
    F --> G[Use Staging + Camber Jacks]
    G --> H[Lifting with Protection]
    H --> I[Complete Bolting & Positioning]

This ensures safe, aligned, and damage-free erection per IRC SP 104 guidelines.

IRC SP 104: Transportation, Handling and Erection - Key Points

1. Transportation & Handling (Clause 2.1.2)

• Route Survey: Check local restrictions before transportation.
• Packing & Fastening: Components must be securely lashed to prevent sliding or falling.
• Protection: Protruding, threaded, and machined parts must be protected and oiled/greased against corrosion.
• Marking: Loose/sub-assembled items should be clearly marked as per erection drawings.
• Small Items: Nuts, bolts, washers, etc., dispatched in containers with detailed lists.
• Avoid Underloading: Maintain full consignments to ensure safety and stability.
• Dispatch Advice: All steel consignments must carry dispatch documents correlating fabrication and erection.

2. Stability & Safety

• Check member stability during loading and transit.
• Use temporary roads/bridges if needed for safe access.

3. Erection

• Follow safe working procedures.
• Inform the engineer of handling and erection plans.

Summary Table: Handling & Transportation Checklist

flowchart TD
    A[Fabrication] --> B[Packing & Fastening]
    B --> C[Route Survey & Restrictions]
    C --> D[Loading & Securing]
    D --> E[Transportation]
    E --> F[Site Access (Temporary Roads)]
    F --> G[Erection with Safe Procedures]
    G --> H[Engineer Approval & Monitoring]

Note: Always adhere strictly to safety norms and engineer instructions during all stages.

IRC SP 104 - Clause 2.2: Erection Scheme and Procedure

Key Points & Specifications

• Approval: Erection scheme, equipment, and methodology must be approved by the engineer.
• Wind Loads: Must be considered based on local wind conditions during erection.
• Ground Stability: Temporary supports should be on stable ground to avoid settlement.
• Support & Alignment:
  • Use staging with blocks and camber jacks.
  • Ensure correct elevation, alignment, and camber.
• Handling:
  • Protect member edges when using chains.
  • Use proper lifting/slinging to avoid permanent deformation.
• Readiness: Start erection only when all resources and foundations are ready.
• Modular Construction: Divide structure into modules; pre-assemble and check fit before erection.
• Difficult Terrain: Conduct trial assembly and load simulation.
• Packing Materials: Ensure availability for proper positioning and bolting.

Suggested Erection Procedure Flow

flowchart TD
    A[Prepare Erection Scheme] --> B[Engineer Approval]
    B --> C[Check Ground Stability]
    C --> D[Pre-assemble Modules]
    D --> E[Trial Assembly (if difficult terrain)]
    E --> F[Set out Supports & Levels]
    F --> G[Start Erection with Staging & Camber Jacks]
    G --> H[Ensure Alignment & Camber]
    H --> I[Secure with Bolts & Drifts]
    I --> J[Inspection & Final Adjustments]

Additional Notes:

• Refer Appendix I for lifting tools and methods.
• Refer Appendix L for erection inspection checklist.
• Use mechanization for large volume erection work.

This ensures safety, quality, and structural integrity during erection.

Key Specifications and Formulas for Joints (IRC SP 104)

1. Bolted Joints (Clause 10.9 & J.6)

• Washers for Class 10.9 Bolts:

  • Two washers required (one under head, one under nut) due to high tension.
  • If DTI washer used:
    • Class 10.9 bolts → 1 DTI + 1 plain washer
    • Class 8.8 bolts → 1 DTI washer only
  • DTI placement depends on rotation:
    • Nut rotated → DTI under head
    • Head rotated → DTI under nut (washer-faced nut per IS:6623 required)

• Surface Preparation (J.5):

  • Steel interface for HSFG bolts: Aluminium metalized coating (~150 µm thick) without overcoating.
  • For existing structures: wire brushing/flame cleaning to remove loose rust/paint.

• Bolt Tension (Table J.2 from IS:4000): Minimum bolt tension (kN) for HSFG bolts:

• Installation: Tighten beyond yield point to induce plastic flow, ensuring proper preload and no gap in joint.

2. Lap Joints (Clause 1.15.23)

• Minimum overlap = 4 × thickness of thinner part.
• At least two transverse or two longitudinal fillet welds required to prevent opening out.
• For longitudinal fillet welds alone:
  • Length ≥ perpendicular distance between welds
  • Spacing ≤ 16 × thickness of thinner part

3. Weld Details (Clause 1.15 & Appendix H)

• Types include:
  • Open Square Butt (with/without backing)
  • Single/Double V, U, J, Bevel Butt Welds
• Transitioning thicker plates

Supporting Documentation and Records in IRC:SP:104-2015 primarily relate to fabrication, welding, inspection, and erection processes. Key points include:

1. Welding Procedure Qualification Record (Clause 1.10 & Appendix C)

• Details to record:
  • Name & Address of Fabricator
  • Base metal preparation
  • Joint design and preparation (with sketches)
  • Welding current, parameters, technique
  • Welder qualification
  • Weld passes with parameters:

2. Post Weld Treatment & Inspection (Clause 1.20)

• Record preheating, inter-pass temperature
• Peening, post weld treatment
• Rectification of weld defects
• Inspection results and any other relevant details

3. Inspection Registers (Appendix A)

• Maintain detailed registers for fabrication and erection inspections.

4. Tolerances and Specifications

• Refer Appendix B for manufacturing tolerances
• Appendix D for roller and knuckle bearing specs and tolerances
• Appendix F for acceptance levels of welds

Summary Table for Documentation

flowchart TD
    A[Fabrication Process] --> B[Welding Procedure Qualification]
    B --> C[Record Welding Parameters]
    C --> D[Post Weld Treatment & Inspection]
    D --> E[Inspection Register]