Safety code for the erection of concrete framed structures

IS 8989 - Scope Summary

Scope:
IS 8989 primarily covers safety codes for scaffolds and ladders (Part I: Scaffolds), focusing on safe erection, use, and dismantling procedures.

Key Points from Scope & Related Clauses

• Safety Precautions (Clause 10.3):

  • Workmen must stand clear of moving vehicles, swinging cranes, and loads being lifted or lowered.
  • Only authorized personnel should handle formwork removal.
  • Use of helmets, gloves, heavy-soled shoes, and safety belts (above 2 m height) is mandatory.

• Formwork Design (Clause 4.1):

  • Design must consider:
    • Span length
    • Concrete setting temperature
    • Dead load + working load
    • Material safety factors

• Formwork Removal (Clause 4.14):

  • Remove forms only after concrete attains sufficient strength.
  • Safety gear mandatory during removal.
  • Prevent wire backlash injuries.

Important Specifications (General)

Reference for Formwork Load Calculation (IS 456 general practice):

[ \text{Total Load} = \text{Dead Load} + \text{Live Load} + \text{Impact Load} ]

• Use appropriate safety factors (typically 1.5 for loads, 1.15 for materials).
• Concrete early strength depends on temperature and curing time (refer IS 456).

flowchart LR
    A[Start: Scaffold Erection] --> B[Design Formwork]
    B --> C{Consider Load Factors}
    C -->|Span, Dead & Working Loads| D[Design with Safety Factor]
    D --> E[Construct Scaffold]
    E --> F[Use Safety Gear]
    F --> G[Concrete Pouring]
    G --> H[Wait for Concrete Strength]
    H --> I[Formwork Removal with Safety Gear]
    I --> J[Clear Work Area]
   

IS 8989 - Handling of Materials: Key Points

1. Precast Concrete Units (Clause 7.6)

   • Handle at specific picking points/devices as per designer.
   • Girders/beams must be braced during transport.
   • Keep members upright to avoid damage.

2. Ramps and Gangways (Clause 5.1.1)

   • Even surface, sufficient width.
   • Skirt boards on open sides for safety.

3. Safety Precautions (Clause 10.3)

   • Workers must stand clear of moving vehicles, cranes, and suspended loads.

Practical Guidelines Summary

Handling Tips:

• Use spreader beams or slings at designated points.
• Avoid sudden movements; maintain load stability.
• Follow IS:7205-1973 for erection safety of steel structures.

flowchart TD
    A[Precast Unit] --> B{Pick at Designated Points}
    B --> C[Use Proper Lifting Devices]
    C --> D[Brace Girders/Beams]
    D --> E[Transport Upright]
    E --> F[Unload Safely]

For detailed safety and handling, refer to IS 7205 and IS 8989 clauses mentioned.

IS 8989: Handling of Plants - Key Points & Specifications

1. Safety & Protective Gear (Clause 2.1)

• Workmen handling cement bags must wear:
  • Goggles
  • Durable close-fitting clothes
• Continuous exposure requires additional:
  • Hand gloves
  • Dust mask
• Adequate clothing to protect from sun-rays and irritants is mandatory.

2. Handling of Precast Concrete Units (Clause 7.6)

• Use specific picking points and devices designated by the designer.
• Girders and beams must be:
  • Braced during transportation
  • Handled to keep members upright

3. Formwork Removal Safety (Clause 4.14)

• Remove forms only after concrete attains sufficient strength as per specifications.
• Only authorized workmen allowed during form removal.
• Protective equipment for form removal:
  • Helmets
  • Gloves
  • Heavy-soled shoes
  • Safety belts if working above 2 m without adequate footing.
• Exercise caution when cutting tensioned tying wires to avoid injury.

Summary Table of Safety Gear for Handling

flowchart TD
    A[Handling Plants] --> B[Precast Concrete Units]
    B --> C[Use specific picking points]
    B --> D[Brace girders/beams during transport]
    B --> E[Keep members upright]
    A --> F[Workmen Safety]
    F --> G[Wear goggles & close-fitting clothes]
    F --> H[Use gloves & dust mask for continuous exposure]
    A --> I[Formwork Removal]
    I --> J[Remove after sufficient strength]
    I --> K[Authorized personnel only]
    I --> L[Wear helmet, gloves, shoes, safety belts]

This ensures safe and efficient handling aligned with IS 8989 requirements.

IS 8989: Formwork and Centering – Key Points & Specifications

Design Considerations (Clause 4.1)

• Design formwork considering:
  • Span length
  • Concrete setting temperature
  • Dead load (self-weight)
  • Working load (wet concrete, workers, equipment)
  • Safety factors for material strength

Centering Materials & Usage (Clause 4.5)

• Use tubular steel centering per manufacturer’s guidelines.
• When combining tubular steel and timber, avoid unequal settlement by careful support alignment.

Centering Inspection & Maintenance (Clause 4.13)

• Continuous inspection during concrete pouring.
• Tighten wedges under vertical supports.
• Adjust screws as needed.
• Protect centering from impacts (vehicles, swinging loads).

Centering Layout & Soil Bearing (Clause 4.10)

• Layout by qualified engineer.
• Check soil bearing capacity for vertical supports.
• Consider weather effects (e.g., wet clay reduces bearing capacity).

Typical Load Calculation for Formwork

Safety Factor

• Typically 1.5 for material strength and load uncertainties.

flowchart TD
    A[Design Formwork] --> B[Calculate Loads]
    B --> C[Dead Load + Live Load + Safety Factor]
    C --> D[Select Materials & Spans]
    D --> E[Prepare Centering Layout]
    E --> F[Check Soil Bearing Capacity]
    F --> G[Install Centering]
    G --> H[Inspect & Adjust During Pouring]
    H --> I[Protect From External Loads]

This summary aligns with IS 8989 clauses and good engineering practice for safe, durable formwork and centering.

IS 8989: Key Specifications for Ramps and Gangways

1. Strength & Support (Clause 5.1)

• Must be adequately strong and evenly supported.
• Railings required on open sides, height sufficient to protect workers.
• Slope should be flat enough or cleats fixed to prevent slipping.
• Keep surfaces free from grease, mud, snow, or obstructions.

2. Surface & Width (Clause 5.1.1)

• Ramps/gangways for material transport must have:
  • Even surface
  • Sufficient width (typically ≥ 0.75 m for worker passage; wider for materials)
  • Skirt boards on open sides to prevent material spillage.

3. Safety & Dismantling (Clause 4.14.1)

• Follow site engineer’s instructions for support dismantling order to maintain stability.

Recommended Ramp Slope

• Maximum slope: 1:12 (8.3%) for safe walking without cleats.
• If slope steeper, install cleats spaced ~300 mm to prevent slipping.

Summary Table

flowchart LR
    A[Ramp/Gangway] --> B{Slope}
    B -- ≤ 1:12 --> C[Flat surface, no cleats]
    B -- > 1:12 --> D[Install cleats @ 300mm spacing]
    A --> E[Railings on open sides ≥ 1.0 m]
    A --> F[Skirt boards ≥ 150 mm on open sides]
    A --> G[Even support & strength]

Note: Always ensure compliance with site-specific instructions and safety norms.

IS 8989 - Prestressed Concrete: Key Points

While IS 8989 focuses on handling, maintenance, and safety, key prestressed concrete design aspects (from general practice and related IS codes like IS 1343) include:

Key Specifications:

• Handling: Use designated picking points; brace girders/beams to keep upright (Clause 7.6).
• Surface Preparation: For bonding precast to in-situ concrete, prepare contact surfaces properly (Clause 9.1).
• Equipment: Follow supplier instructions strictly for prestressing operations (Clause 6.1).

Fundamental Formulas (from IS 1343 for prestressing):

• Stress in tendon after losses: [ f_{p} = f_{pi} - \Delta f_{loss} ] where ( f_{pi} ) = initial prestress, ( \Delta f_{loss} ) = total prestress losses.

• Ultimate flexural strength: [ M_u = f_{pu} \times A_p \times (d - a/2) ] where ( f_{pu} ) = stress in tendon at ultimate load, ( A_p ) = area of prestressing steel, ( d ) = effective depth, ( a ) = depth of equivalent stress block.

Typical Table Extract (Losses in Prestress):

flowchart TD
    A[Prestressing Operation] --> B[Initial Stressing]
    B --> C[Losses: Elastic Shortening]
    C --> D[Losses: Creep & Shrinkage]
    D --> E[Losses: Relaxation & Friction]
    E --> F[Effective Prestress in Tendon]

Note: For detailed design, refer to IS 1343 (Prestressed Concrete) along with IS 8989 for handling and maintenance.

IS 8989: Key Points on Erection of Prefabricated Members

1. General Requirements (Clause 7.7)

• Strictly follow designer-specified method of assembly and erection.
• After placing a unit, provide temporary supports/connections before releasing lifting equipment.
• Establish permanent structural connections as soon as possible.

2. Temporary Supports (Clause 7.4)

• Use temporary scaffolding with adequate strength at predetermined support points during lifting and positioning.
• Supports must prevent any movement or damage until permanent connections are made.

3. Centering (Clause 4.5)

• Use tubular steel centering per manufacturer instructions.
• When combining tubular steel and timber centering, ensure uniform load distribution to avoid unequal settlement.

Summary Table: Erection Support Guidelines

flowchart TD
    A[Start: Prefab Member Lifted] --> B[Place at Position]
    B --> C[Install Temporary Supports]
    C --> D[Release Lifting Equipment]
    D --> E[Establish Permanent Connections]
    E --> F[Complete Erection]

Note: Regular inspection of prestressing jacks (Clause 6.9) is essential but not directly related to erection steps.

IS 8989: Use of Heaters and Curing – Key Points

Clause 8.1: Use of Heaters

• Heaters (coal, liquid, gas, etc.) used to heat aggregates/materials or maintain curing temperature must be frequently checked for proper functioning.
• Safety precautions are mandatory to avoid hazards related to fuel use.
• Maintain curing temperature as per design requirements to ensure proper hydration and strength gain.

Curing Temperature Guidelines (Typical Practice)

General Specifications for Heated Concrete (from IS 8989 & related codes)

• Formwork removal only after concrete attains sufficient strength.
• Ensure safe working conditions during formwork removal (helmets, gloves, safety belts).
• Formwork design must consider:
  • Dead load + working load
  • Temperature effects (heated concrete expands/contracts)
  • Safety factors for materials

Summary Diagram: Heated Concrete Process

flowchart TD
    A[Heating Aggregates & Materials] --> B[Mixing Concrete]
    B --> C[Placing Concrete]
    C --> D[Maintaining Curing Temperature]
    D --> E[Formwork Support & Safety Checks]
    E --> F[Formwork Removal After Strength Gain]

Note: For precise temperature/time schedules and heater specifications, refer to project-specific design or related IS codes like IS 456 (Plain and Reinforced Concrete).

IS 8989: Structural Connections - Key Points & Specifications

1. Connection Types & Materials

• Timber Posts (Clause 4.8):
  • Vertical joints must be properly designed.
  • Connections are typically bolts and nuts.
  • Avoid use of rusted or spoiled threaded bolts/nuts.

2. Centering Connections (Clause 4.5)

• Use tubular steel centering as per manufacturer instructions.
• For combined tubular steel and timber centering, ensure no unequal settlement under load.

3. Assembly & Erection (Clause 7.7)

• Follow the designer’s specified method strictly.
• Provide temporary supports/connections immediately after erection before releasing lifting equipment.
• Establish permanent connections at the earliest.

General Recommendations (from engineering practice):

Important:

• Ensure tight, rust-free connections for durability.
• Temporary supports are critical for stability during erection.

flowchart TD
    A[Design Connections] --> B[Select Bolt Type & Size]
    B --> C[Assemble Components]
    C --> D[Temporary Supports]
    D --> E[Release Lifting Equipment]
    E --> F[Establish Permanent Connections]

This ensures safety and structural integrity during construction.

IS 8989: General Safety Precautions (Clause 10.3 & Related Clauses)

Key Safety Guidelines:

• Personnel Safety:

  • Workers must stand clear of moving vehicles, swinging cranes, and loads being lifted or lowered.
  • Only authorized personnel should be present during formwork removal.
  • Use helmets, gloves, heavy-soled shoes, and safety belts (if working above 2 m without secure footing).

• Handling Materials:

  • Welding precautions must be strictly followed during joint preparation.
  • Electric power for onsite work must be stepped down to safe levels.

• Formwork Removal:

  • Remove forms only after concrete attains sufficient strength as per specifications.
  • Prevent injury from cutting tensioned tying wires by controlling backlash.

Summary Table for Safety Equipment Use

Safety Workflow for Formwork Removal

flowchart TD
    A[Check concrete strength] --> B{Sufficient strength?}
    B -- Yes --> C[Allow formwork removal]
    B -- No --> D[Delay removal]
    C --> E[Equip workers with PPE]
    E --> F[Remove formwork carefully]
    F --> G[Clear site]

For detailed procedures, refer also to IS 7205-1973 (steel erection safety) and welding safety standards.