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IS 10792:1984 is the Indian Standard (BIS) for recommendations for formwork for concrete. This code provides recommendations for the design, fabrication, erection, and stripping of formwork for in-situ concrete structures. It covers materials, design loads, construction practices, tolerances, and minimum time periods before striking formwork to ensure safety and quality.
Provides recommendations for the design, construction, and removal of formwork for concrete structures.
Overview
Status
Current
Usage level
Frequently Used
Domain
Structural Engineering — Scaffolding, Formwork and Construction Equipment
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! This 1984 version has been superseded by IS 10792:2022. The new version should be consulted for current projects as it contains updated provisions.
! Stripping times are highly dependent on ambient temperature and type of cement. The code specifies values for temperatures above 15°C using Ordinary Portland Cement; adjustments are needed for other conditions.
! For multi-story construction, ensure that the supporting floors have gained sufficient strength before being subjected to the load of freshly placed concrete from the floor above.
Provides comprehensive guidance on design, construction, and materials for concrete formwork.
BS 5975:2019British Standards Institution, UK
HighCurrent
Code of practice for temporary works procedures and the permissible stress design of falsework
Covers falsework design and procedural control of all temporary works, including formwork.
AS 3610.1:2018Standards Australia, Australia
HighCurrent
Formwork for concrete - Part 1: Specifications
Directly specifies requirements for the design, fabrication, erection, and stripping of formwork.
EN 12812:2008European Committee for Standardization, Europe
MediumCurrent
Falsework - Performance requirements and general design
Focuses on the performance and design of falsework, the structural support system for formwork.
Key Differences
≠IS 10792 is based on a Permissible/Allowable Stress Design (ASD) philosophy, whereas modern international standards like ACI 347R and AS 3610 are aligned with Limit State Design (LSD) or Load and Resistance Factor Design (LRFD) principles.
≠IS 10792 specifies formwork removal times prescriptively based on days and ambient temperature. Modern standards like ACI 347R strongly recommend basing removal on achieving a specified percentage of the concrete's design strength, a performance-based approach.
≠The minimum specified live load in IS 10792 (0.75 kN/m²) is significantly lower than that recommended in standards like ACI 347R (2.4 kN/m²), reflecting different assumptions about modern construction site loads and equipment.
≠International standards like BS 5975 are far more detailed on procedural controls, requiring formal roles like a Temporary Works Coordinator (TWC) and comprehensive design checks, which are not explicitly defined in IS 10792.
Key Similarities
≈All standards share the fundamental principle that formwork must be strong enough to support all imposed loads without failure and stiff enough to maintain the specified shape and dimensional tolerances of the concrete structure.
≈All codes recognize and provide methods for calculating the lateral pressure exerted by fresh concrete, considering factors like pour rate, temperature, and mix properties, as this is a critical design load.
≈The types of loads to be considered are consistent across all standards, including dead loads (concrete, reinforcement, formwork self-weight), live loads (workers, equipment), and environmental loads (wind).
≈All standards specify permissible deflection limits for formwork members to ensure the final concrete surface has the required accuracy, appearance, and serviceability.
Parameter Comparison
Parameter
IS Value
International
Source
Minimum Live Load on Slabs
75 kg/m² (0.75 kN/m²)
50 psf (2.4 kN/m²) for workers and equipment
ACI 347R-14
Permissible Deflection (General)
Span / 270
Span / 240 (unless specified otherwise by the engineer)
ACI 347R-14
Minimum Horizontal Load (for Bracing)
2% of total dead load
The greater of 1.5 kN/m of floor edge or 2% of total dead load
ACI 347R-14
Basis for Formwork Striking Time
Prescriptive time in days based on temperature and span (e.g., 7 days for slabs > 6m)
Performance-based: based on concrete achieving a specified percentage of its design strength
ACI 347R-14
Tolerance for Plumb (Verticality)
1 in 500 of height, max 25 mm total
Varies by finish class; for Class A: 6 mm in 3 m
AS 3610.1:2018
Design Philosophy
Permissible Stress Design
Limit State Design / LRFD principles
General (ACI, AS, EN)
Timber Design Stress Basis
Based on IS 883:1970 (Withdrawn)
Based on current national timber design codes (e.g., NDS for USA, Eurocode 5 for Europe)
General (ACI, BS)
⚠ Verify details from original standards before use
Key Values7
Quick Reference Values
Stripping time for vertical faces (columns, walls)16 to 24 hours
Stripping time for slab soffits (props re-fixed immediately)3 days
Stripping time for beam soffits (props re-fixed immediately)7 days
Stripping time for slab props (span up to 4.5m)7 days
Stripping time for beam/arch props (span up to 6m)14 days
Maximum deviation from vertical for columns/walls±6 mm per 3 m height
Tolerance in cross-sectional dimensions of columns/beams+12 mm / -6 mm
Key Formulas
P = γh — Basic formula for lateral pressure of fluid concrete (where P is pressure, γ is unit weight, h is depth of fluid concrete)
Tables & Referenced Sections
Key Tables
Table 1 - Recommended Tolerances for Finished Concrete Structures
Table 2 - Minimum Period Before Striking Formwork
Key Clauses
Clause 6 - Loads on Formwork
Clause 7 - Design of Formwork
Clause 9 - Tolerances in Finished Concrete
Clause 11 - Striking of Formwork (Stripping Times)
What is the minimum time to remove formwork from a concrete column?+
For vertical faces like columns, walls, and large beam sides, formwork can be removed after 16 to 24 hours. (Clause 11.2)
When can I remove the bottom formwork (soffit) of a 4m slab?+
Soffit formwork can be removed after 3 days if props are re-fixed immediately. The props themselves can be removed after 7 days for spans up to 4.5m. (Table 2)
What are the main loads to consider when designing formwork?+
The design must account for the dead load of wet concrete, self-weight of the formwork, live loads from workers and equipment, and the lateral pressure exerted by the fresh concrete. (Clause 6)
What is the acceptable tolerance for the dimensions of a concrete beam?+
The tolerance for cross-sectional dimensions of members like beams and columns is +12 mm and -6 mm. (Table 1)