Structure & Scaffolding Installation

Standard Operating Procedure for scaffolding erection and structural installation including towers, ensuring worker safety, structural integrity, and compliance with IS 4014, IS 3696, and IS 800 safety standards for the 50MWP Ampyr Solar Project in Dhule, Maharashtra.

Duration: 7-14 days Team: 6-12 workers Risk Level: High

1. Purpose

To establish a standardized procedure for scaffolding erection and structural installation including transmission towers, support structures, and temporary access platforms, ensuring safety, stability, and compliance with industry standards while minimizing risks associated with working at heights and handling heavy components.

2. Scope

This SOP covers all aspects of scaffolding and structural installation activities including pre-assembly of components, erection of temporary support systems, positioning and alignment of structural members, connection methodologies, and post-installation checks for residential, commercial, industrial, and utility-scale projects like the 50MWP Ampyr Solar Project in Dhule, Maharashtra.

3. Responsibilities

Project Manager

Overall project oversight and compliance with regulations

Site Engineer

Technical guidance and quality control monitoring

Scaffold Supervisor

Supervision of scaffold erection and inspection

Scaffolders & Technicians

Perform scaffolding erection and structural assembly

Quality Inspector

Material inspection and adherence to safety codes

Safety Officer

Implementation of safety protocols and hazard mitigation

Equipment Operators

Operation of cranes, hoists, and lifting equipment

Competent Person

Authorized scaffold inspector as per IS 3696

4. Equipment and Materials Required

Scaffolding Components

Standards, ledgers, transoms, base plates, couplers, planks, ladders

Structural Components

Steel sections, towers, lattice members, bolts, plates, angles

Lifting Equipment

Mobile cranes, tower cranes, chain blocks, slings, shackles

Tools

Torque wrenches, spanners, impact drivers, levels, plumb bobs

Welding Equipment

Welding machines, electrodes, cutting torches, PPE for welding

Safety Equipment

Harnesses, lanyards, helmets, gloves, safety shoes, high-visibility vests

Signage & Barriers

Warning signs, barricade tape, exclusion zone markers

Communication Devices

Two-way radios, signal horns, hand signals for crane operations

5. Procedure

1
Pre-Work Assessment and Planning
  • Identify and mark all structural components according to drawing
  • Assemble tower sections/panels at ground level where possible
  • Verify bolt hole alignment and structural member orientation
  • Apply corrosion protection to connection points if required
  • Pre-torque bolted connections to manufacturer's specifications
  • Attach lifting points and rigging at designated locations
  • Calculate and verify weights of pre-assembled components
  • Mark center of gravity and lift points for balanced lifting
  • Conduct trial fit of critical connections before final assembly
2
Scaffolding Erection
  • Prepare ground with base plates and sole boards on firm, level surface
  • Erect vertical standards following a 3:1 height-to-base ratio rule
  • Install ledgers horizontally at maximum 2m intervals as per IS 4014
  • Place transoms at maximum 1.2m centers as per load calculations
  • Add diagonal bracing at 30-45° angles for lateral stability
  • Install guardrails at heights of 0.5m and 1.0m as per IS 3696
  • Add toe boards with minimum 150mm height to prevent falling objects
  • Provide safe access with ladders extending 1m above landing point
  • Tie scaffold to main structure at every 4m height and 6m length
  • Install proper work platforms with fully boarded decks
  • Ensure maximum gap of 25mm between adjacent planks
  • Conduct inspection by competent person before use
3
Tower Structure Pre-Assembly
  • Review approved structural and scaffolding drawings
  • Conduct site assessment for ground conditions and overhead hazards
  • Prepare risk assessment and method statement (RAMS)
  • Verify qualification of workers (scaffolders per IS 3696, riggers, etc.)
  • Establish exclusion zones and drop zones around work area
  • Identify anchor points for fall protection systems
  • Conduct toolbox talk to review procedures and safety requirements
  • Inspect all materials and equipment prior to use
4
Structural Installation
  • Position crane and outriggers on firm, level ground
  • Verify lifting capacity against load charts for actual configuration
  • Check wind conditions before lifting (maximum 38 km/h for safe lifting)
  • Attach tag lines to control load movement (minimum 15m long)
  • Establish clear communication protocol between riggers and operator
  • Lift and position base sections first, ensuring proper alignment
  • Temporarily secure components before final fixing
  • Install permanent connections using proper sequence:
  • Start from center and work outward for beam connections
  • Install all bolts in a connection before final tightening
  • Follow zigzag pattern for multi-bolt connections
  • Apply specified torque using calibrated tools as per IS 4000
  • Mark completed connections with paint or marker
  • Install subsequent levels/sections following the same procedure
  • For tower structures, install diagonals and cross members as per sequence
  • Continuously check vertical alignment with total station or plumb bob
5
Final Structural Adjustments and Checks
  • Perform final structure plumbing with total station (max deviation ±5mm)
  • Check column straightness with maximum allowable camber of span/1000
  • Perform final tightening of all bolts to specified torque values
  • Apply secondary torque marks for visual verification
  • Install any remaining bracing or stability components
  • Apply touch-up paint to connections and damaged surfaces
  • Complete any required welding of permanent connections
  • For tower structures, verify antenna mounting provisions
  • Install any specified grounding systems
  • Remove temporary lifting attachments and other aids
  • Conduct final inspection with project engineer
6
Scaffolding Dismantling
  • Ensure structure is stable and secure before removing scaffolding
  • Remove all tools and materials from scaffold platforms
  • Establish exclusion zone around dismantling area
  • Dismantle in reverse order of erection with top components first
  • Lower components using rope and pulley systems (never drop)
  • Maintain minimum two levels of guardrails during dismantling
  • Remove ties only as dismantling progresses
  • Stack components properly to prevent damage
  • Clean and inspect components before storage

6. Quality Control Measures

Dimensional Checks

Verify alignments within ±5mm tolerance per IS 800

Visual Inspection

Check for defects, damage, and correct component use

Torque Verification

Check 10% of all bolts with calibrated torque wrench

Plumb and Level

Maximum deviation of height/500 for vertical elements

NDT Testing

For critical welds as per IS 822 requirements

Load Tests

Scaffold platforms at 1.25 times intended load

Documentation

Maintain inspection records and material certificates

Coating Inspection

Verify coating thickness and coverage on connections

7. Safety Measures

Personal Protection

Always wear full PPE including harness for heights above 1.8m

Wind Conditions

Stop work if wind speeds exceed 38 km/h

Electrical Safety

Maintain minimum 6m clearance from power lines

Load Management

Never exceed scaffold capacity (2.5 kN/m² typical)

Crane Safety

Use designated signaler and maintain lift plan

Exclusion Zones

Establish no-entry areas under lifting operations

Weather Monitoring

Suspend operations during storms or heavy rain

Emergency Response

Have rescue plan for potential falls or entrapments

8. Tower-Specific Construction Requirements

Foundation Interface
  • Verify foundation anchor bolt pattern and elevation before installation
  • Check anchor bolt projection length (minimum 6D + 30mm)
  • Install leveling nuts and washers on anchor bolts
  • Set base plates to correct elevation (±3mm tolerance)
  • Apply non-shrink grout with minimum 50MPa strength
  • Allow grout to cure (minimum 7 days) before loading
Tower Assembly Sequence
  • Follow manufacturer's recommended assembly sequence
  • Install base section first with temporary guys if required
  • Add subsequent sections maintaining verticality (±1:1000)
  • Install diagonal members and cross bracing at each level
  • Verify bolt tensions for each type and size:
  • M12 (Grade 8.8): 70-80 Nm
  • M16 (Grade 8.8): 170-190 Nm
  • M20 (Grade 8.8): 330-360 Nm
  • M24 (Grade 8.8): 570-630 Nm
  • Install platforms and ladder systems as per design
  • Add aviation warning lighting if height exceeds 45m
  • Install lightning protection and earthing system
Tensioning Systems (For Guyed Towers)
  • Verify guy anchor positions (±50mm tolerance)
  • Install guy wires with proper sag (1/40 to 1/60 of span)
  • Use calibrated tension meters for guy wire adjustment
  • Apply initial tension (10-15% of breaking strength)
  • Adjust guys systematically working around the tower
  • Install safety guards at all tension hardware

9. Documentation and Compliance

Maintain scaffold inspection register as per IS 3696
Document torque verification for all critical connections
Maintain photographic evidence at key installation stages
Record daily work progress and hold points
File material test certificates and mill certificates
Document load test results and deflection measurements
Maintain records of nonconformances and corrective actions
Compile as-built drawings showing actual dimensions

10. Troubleshooting Common Issues

Misaligned Bolt Holes

Problem: Bolt holes not aligning during assembly.

Solution: Use tapered alignment pins to guide components. Check for deformation or damage. Use drift pins cautiously (never hammer bolt threads). For severe misalignment, refer to structural engineer before enlarging holes.

Scaffold Instability

Problem: Scaffold wobbling or showing signs of instability.

Solution: Increase number of ties to structure. Add additional diagonal bracing. Check and improve base conditions. Reduce height-to-base ratio. Consider using buttress/raker bracing for support.

Tower Plumbness Issues

Problem: Tower leaning or out of plumb beyond allowable tolerances.

Solution: For guided towers, adjust guy wire tensions incrementally. For self-supporting towers, check foundation levelness. Use hydraulic jacks at base to make minor corrections before final bolting. For significant issues, consult structural engineer.

Bolt Torque Issues

Problem: Unable to achieve specified torque values.

Solution: Check bolt grade and size are correct. Clean and lubricate threads if needed (use specified lubricant only). Inspect for thread damage. Verify torque wrench calibration. Replace bolts if necessary rather than exceeding maximum torque.

11. References and Standards

IS 4014 (Parts 1 & 2): Code of practice for steel tubular scaffolding
IS 3696 (Parts 1 & 2): Safety code for scaffolds and ladders
IS 800:2007: Code of practice for general construction in steel
IS 4000:1992: Code of practice for high strength bolts
IS 822:1970: Code of procedure for inspection of welds
IS 1161:1998: Steel tubes for structural purposes
IS 875 (Part 3): Wind loads on structures
IS 1893:2016: Criteria for earthquake resistant design of structures

12. Best Practices and Tips

Pre-installation Meeting

Conduct thorough pre-installation meeting with all stakeholders

Component Management

Use color-coding system to identify different types of structural members

Bolt Protection

Apply temporary caps to projecting bolts to prevent injuries

Sequence Planning

Plan installation sequence to minimize crane movements

Weather Monitoring

Install weather monitoring station for critical tower installations

Buddy System

Implement buddy system for all height work with no lone working

Component Layout

Stage materials in order of installation to minimize handling

Precision Tools

Use total station for precise alignment of critical structures

13. Conclusion

By following this Standard Operating Procedure, scaffolding and structural installation work can be executed efficiently, safely, and to the highest quality standards. Proper execution of these procedures will ensure structural integrity, worker safety, and compliance with all relevant codes and standards. This SOP should be reviewed periodically and updated based on field experiences and changes in regulations.

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