Code of Practice for Construction of Floor and Roof with Joists and Filler Blocks, Part 3: With Precast Hollow Clay Block Joists and Hollow Clay Filler Blocks
1981 Edition

Overview of IS 6061 Part 3 (1981) – Scope and Key References

Scope:
This section defines construction practices for floors and roofs utilizing joists and filler blocks, emphasizing structural clay block slab systems and associated waterproofing methods.

Essential Waterproofing Standards (Clause 7.3)

Applicable codes for roof waterproofing include:

Structural Clay Block Slab Design Coefficients (Clause 5.6.1)

Bending Moment Coefficients

Shear Force Coefficients

Note: Multiply these coefficients by total design load and effective span to determine moments and shear forces.

Diagram: Roof Waterproofing Options

graph LR
A[Roof Waterproofing Methods] --> B[Bitumen Felts (IS 1346)]
A --> C[Lime Concrete (IS 3036)]
A --> D[Bitumen Mastic (IS 4365)]
A --> E[Polyethylene Film (IS 7290)]

Use these standards and coefficients for precise design and detailing.

Design Fundamentals for Structural Clay Block Slabs (IS 6061 Part 3)

Critical Clauses:

• Clause 5.1: Design must follow structural analysis described in Clauses 5.2 to 5.9.
• Clause 5.3: Two-stage loading design approach is required (construction phase and service phase).
• Clause 5.9.2: Shear stresses should not exceed allowable limits.

Key Design Tables (Clause 5.6.1):

Bending Moment Coefficients (Multiply by total design load × effective span)

Shear Force Coefficients (Multiply by total design load)

Calculation Formulae:

• Bending Moment, M = Coefficient × Design Load × Effective Span
• Shear Force, V = Coefficient × Design Load

Notes:

• Consider both construction and service loading stages.
• Verify shear stresses remain within permissible bounds.
• Effective span should be determined based on support configurations.

flowchart TD
    A[Begin: Clay Block Slab Design] --> B[Identify Loads: Dead + Imposed]
    B --> C[Select Appropriate Coefficients]
    C --> D[Compute Bending Moments and Shear Forces]
    D --> E[Verify Structural Requirements]

Materials Overview per IS 6061 Part 3 (1981)

• Waterproofing Codes (Clause 7.3): Roof waterproofing should follow one of these Indian Standards:

  • IS 1346-1976: Bitumen felts
  • IS 3036-1980: Lime concrete for waterproof finishes
  • IS 4365-1967: Bitumen mastic application
  • IS 7290-1973: Polyethylene film usage

• Material Details: Consult respective IS codes for properties and application procedures, such as:

  • Bitumen felts: type, thickness, application (IS 1346)
  • Lime concrete: mix proportions, curing (IS 3036)
  • PVC sheets: flexibility, thickness (IS 4365)

• Design Coefficients for Clay Block Slabs (Clause 5.6.1):

• Multiply coefficients by design load and effective span accordingly.

Diagram: Material Specification Flow

graph TD
  A[Roof Waterproofing Methods] --> B[Bitumen Felts (IS 1346)]
  A --> C[Lime Concrete (IS 3036)]
  A --> D[Bitumen Mastic (IS 4365)]
  A --> E[Polyethylene Film (IS 7290)]
  F[Clay Block Slab Design] --> G[Bending Moment Coefficients]
  F --> H[Shear Force Coefficients]

For detailed material characteristics and usage, always refer to the associated Indian Standards.

Guidelines for Fabrication and Curing of Precast Hollow Clay Block Joists (IS 6061 Part 3)

Fabrication (Clause 4.2)

• Use wetted and surface-dry hollow clay blocks.
• Align blocks end-to-end placing the broader base on the casting platform.
• Bond blocks with mortar mix 1:3 cement to sand or equivalent cement-lime mortar.
• Position two cleaned, oiled timber planks along the sides, secured by mild steel clamps.
• Insert designed reinforcement bars inside the hollow spaces, maintaining proper cover.
• Fill hollows with a minimum M15-grade concrete.
• Remove side planks after 45 to 90 minutes based on ambient conditions.

Curing (Clause 4.3)

• Commence water curing on the casting platform one day post-casting.
• After approximately four days, when concrete attains sufficient handling strength, invert joists and transfer to the curing yard.
• Continue moist curing without interruption for at least 14 days from casting.

Additional Details

• Follow IS standards for steel reinforcement bars selection.
• Fill gaps between joists with M15 concrete as specified.
• Apply negative reinforcement for cantilever or partially fixed joists.

Process Summary Table

flowchart TD
    A[Place wetted clay blocks] --> B[Bond with mortar]
    B --> C[Attach side wooden planks with clamps]
    C --> D[Insert reinforcement bars]
    D --> E[Fill hollow cores with M15 concrete]
    E --> F[Remove planks after 45-90 mins]
    F --> G[Begin curing on platform (Day 1)]
    G --> H[Invert joists and move to curing yard (Day ~4)]
    H --> I[Continue moist curing for 14 days]

Load Specifications and Arrangements (IS 6061 Part 3)

Design Loads (Clause 5.2)

• Live loads determined as per IS 875-1964.
• Design considers two loading phases for prefabricated clay block slabs:
  • Phase 1: Self-weight plus construction-related loads.
  • Phase 2: Superimposed dead load combined with live load.

Loading Configurations for Continuous Slabs (Clause 5.6)

Load scenarios include:

Bending Moment Coefficients (Clause 5.6.1, Table 1)

Note: Multiply coefficients by total design load and effective span to determine bending moments.

Shear Force Coefficients (Clause 5.6.1, Table 2)

Multiply coefficients by total design load to obtain shear forces.

Moment Calculation Formula:

[ M = C_m \times w \times L ]

Where:

• (M) = Bending moment
• (C_m) = Moment coefficient
• (w) = Total design load per unit length
• (L) = Effective span length

Construction and Assembly Guidelines for Joists and Hollow Clay Filler Blocks (IS 6061 Part 3)

Key Instructions:

• Joists are spaced according to design criteria, typically 450 to 600 mm center-to-center.
• Hollow clay filler blocks are positioned firmly between joists to create floor or roof slabs.
• To ensure staggered joints and improved load transfer, half-length filler blocks are used at joint interfaces (Clause 6.1.1).
• Blocks are bedded with mortar to maintain tight joints.
• Reinforcement such as mild steel rods or mesh may be placed over filler blocks before plastering.

Essential Details:

• Provide adequate bearing length on walls, generally a minimum of 100 mm.
• Maintain uniform filler block thickness for level surfaces.
• Ensure sufficient curing of mortar and blocks for strength development.

Conceptual Diagram (Fig. 3):

graph LR
    A[Wall Support] --> B[Precast Joist]
    B --> C[Filler Block (half units at joints)]
    C --> D[Precast Joist]
    D --> E[Wall Support]
    style B fill:#f9f,stroke:#333,stroke-width:2px
    style C fill:#bbf,stroke:#333,stroke-width:1px

This method promotes a robust, crack-resistant slab system with effective load distribution.

IS 6061 Part 3 (1981) – Finishing Floors and Roofs: Essential Points

Applicable IS Codes for Finishing (Clause 7.1.1)

Roof Waterproofing Standards (Clause 7.3)

• Bitumen felts (IS 1346-1976)
• Lime concrete (IS 3036-1980)
• Bitumen mastic (IS 4365-1967)
• Polyethylene film (IS 7290-1973)

Summary Table for Finish Selection

For other finishes, consult respective IS codes for detailed guidance.

Guidelines for Reinforcement Detailing (IS 6061 Part 3)

Reinforcement Standards:

• Use steel bars complying with IS 432 (Part 1)-1966, IS 1139-1966, or IS 1786-1979.
• Maintain minimum clear cover of 15 mm around reinforcement (Clause 6.5.3).
• Splicing of reinforcement bars should be avoided wherever feasible.

Design Parameters:

Table 1: Bending Moment Coefficients

Table 2: Shear Force Coefficients

Summary:

• Calculate bending moments and shear forces by multiplying coefficients with respective design loads.
• Ensure minimum cover and avoid reinforcement splices.
• Follow IS 456 for slab depth and deflection control.

flowchart TD
    A[Input Design Load] --> B[Compute Moments]
    A --> C[Compute Shear Forces]
    B --> D[Apply Bending Moment Coefficients]
    C --> E[Apply Shear Force Coefficients]

Although IS 6061 Part 3 (1981) does not explicitly address handling, storage, and transport, standard engineering practices and related IS codes apply:

Handling

• Employ slings, chains, or clamps designed to prevent damage to precast elements.
• Distribute the loads evenly to avoid bending or distortion.
• Avoid dropping or impact during handling.

Storage

• Store precast components on flat, level surfaces with supports spaced typically every 1.5 to 2 meters for beams.
• Protect from moisture and corrosive environments.
• Stack elements with spacers to enable air circulation.

Transportation

• Secure loads firmly to prevent shifting during transit.
• Use padding materials to protect surfaces.
• Adhere to vehicle capacity and weight limitations.

Typical Support Spacing for Storage

flowchart LR
    A[Handling] --> B[Use appropriate slings/clamps]
    A --> C[Ensure even load distribution]
    D[Storage] --> E[Place on flat, level surface]
    D --> F[Support spacing every 1.5-2.5 m]
    D --> G[Protect from moisture]
    H[Transportation] --> I[Secure loads firmly]
    H --> J[Use cushioning]
    H --> K[Respect vehicle limits]

For more detailed procedures, consult IS 800 and IS 875 standards.

Support and Bearing Requirements as per IS 6061 Part 3

Bearing Lengths (Clause 6.3)

• Minimum bearing length along the span: 75 mm
• Minimum bearing length at slab ends: 20 mm

Bending Moment Coefficients (Clause 5.6.1, Table 1)

Moment (M) = Coefficient × Total Design Load (W) × Effective Span (l)

Shear Force Coefficients (Clause 5.6.1, Table 2)

Shear Force (V) = Coefficient × Total Design Load (W)

Moments for Simply Supported Slabs (Clause 5.7)

• Positive moment at midspan: [ M = \frac{W l^2}{8} ]
• Negative moment at supports (with partial fixity): [ M = \frac{W l^2}{24} ]

Summary:

• Apply coefficients from Tables 1 and 2 for continuous slabs with uniform loads.
• Maintain minimum bearing lengths of 75 mm along spans and 20 mm at ends.
• Design slabs considering partial restraints and simple support conditions.

Moment and Shear Force Computations
IS 6061 Part 3: Essential Formulas and Tables

Bending Moment Coefficients (Clause 5.6.1, Table 1)

Moment (M) = Coefficient × Total Design Load × Effective Span

Shear Force Coefficients (Clause 5.6.1, Table 2)

Shear Force (V) = Coefficient × Total Design Load

Shear Stress Formula (Clause 5.9)

[ q = \frac{V}{b \times d} ]

Where:

• (V) = Shear force at the section
• (b) = Minimum web width
• (d) = Effective depth

Additional Notes:

• For slabs with unequal spans or support loads, design using the larger negative moment (Clause 5.6.1.1).
• Applicable primarily for slabs with three or more spans, with span lengths within 15% difference.

flowchart TD
    A[Total Design Load] --> B[Calculate Moments]
    B --> C[Use Table 1 Coefficients]
    C --> D[End Span Moment]
    C --> E[Interior Span Moment]

Quality Control and Safety Guidelines in IS 6061 Part 3

1. Quality Control Standards:

• Waterproofing must meet requirements in these IS codes:
  • IS 1346-1976 (Bitumen felts waterproofing)
  • IS 3036-1980 (In-situ cement concrete flooring)
  • IS 4365-1967 (Flexible PVC flooring)
  • IS 7290-1973 (Burnt clay brick flooring)

2. Design Coefficients Utilization (Clause 5.6.1):

3. Safety and Compliance:

• Test results must be rounded in accordance with IS 2-1960.
• Maintain accuracy in significant digits as specified.
• Follow referenced IS codes strictly to ensure construction safety and durability.

flowchart TD
    A[Initiate Design & Construction] --> B[Select Waterproofing per IS Codes]
    B --> C[Apply Bending Moment Coefficients]
    C --> D[Apply Shear Force Coefficients]
    D --> E[Conduct Quality Control Tests]
    E --> F[Round off Values per IS 2-1960]
    F --> G[Ensure Safety & Compliance]
    G --> H[Obtain Construction Approval]

Summary: Employ the bending moment and shear force coefficients for load designs and adhere to all referenced IS standards for quality and safety.

IS 6061 Part 3 (1981): Key Referenced Indian Standards

This code references several important IS standards relevant to waterproofing and roofing:

Waterproofing-Related Codes (Clause 7.3)

Additional Relevant Codes

• IS 2118-1980: Jack-arch built-up floor and roof construction
• IS 2119-1980: Brick-cum-concrete composite floor/roof systems
• IS 2792-1964: Stone slabs over joist floors
• IS 2858-1964: Roofing using Mangalore tiles
• IS 6061 (Parts I, II, IV): Construction with joists and filler blocks of various materials
• IS 6332-1971: Precast doubly curved shell units for floor and roof

SI Units Overview

Diagram: IS 6061 Part 3 Reference Overview

graph TD
    A[IS 6061 Part 3 - Waterproofing & Roofing] --> B[IS 1346 - Bitumen Felts]
    A --> C[IS 3036 - Lime Concrete]
    A --> D[IS 4365 - Bitumen Mastic]
    A --> E[IS 7290 - Polyethylene Film]