IS CODES FOR RCC STRUCTURAL DESIGN

This article describes the basic codes for RCC structural design as per Indian standard codes. The structural design of reinforced concrete structures should be carried so as to conform to the Indian codes for reinforced concrete design, published by Bureau of Indian standards, New Delhi.

Purpose of design codes:

National building codes have been formulated in different countries to lay down guidelines for the design and construction of structures. The codes have been evolved from the collective wisdom of expert structural engineers, gained over the years. These codes are periodically revised to bring them in line with current research, and often current trends.

Following are the functions of design codes:

Firstly, the design codes ensure adequate structural safety, by specifying certain essential minimum reinforcement for design.

Secondly, they render the task of the designer relatively simple, often the result of sophisticate analysis is made in the form of a simple formula or chart.

Thirdly, the codes ensure a measure of consistency among different designers.

Finally, they have some legal validity in that they protect the structural designer from any liability due to structural failures that are caused by inadequate supervision and/or faulty material and construction.

Following are the design codes in India:

(i) IS456: 2000 – plain and reinforced concrete – code of practice (fourth revision)

(ii) Loading standard codes

The loads to be considered for structural design are specified in the following loading standards:

IS 875 (Part 1 to 5) : 1987 – code of practice for design loads (other than earthquake) for buildings and structures (second revision).

Part – 1: Dead loads

Part – 2: Imposed (Live) loads

Part – 3: Wind loads

Part – 4: Snow loads

Part – 5: Special loads and load combinations

IS 1893: 2002 – criteria for earthquake resistant design of structure (fourth revision).

IS 13920: 1993 – ductile detailing of reinforced concrete structures subject to seismic forces.

Design Handbooks:

The bureau of Indian Standards have also published the following handbooks which serve as useful supplement to the 1978 version of the codes. Although the handbooks need to be updated to bring them in line with the recently revised (2000 version) of the code, many of the provisions continue to be valid (especially with regard to structural design provisions).

SP 16 – 1980 – Design Aids (for Reinforced Concrete) to IS456: 1978

SP 24: 1983 – Explanatory handbook on IS 456: 1978

SP34: 1987 – Handbook on Concrete Reinforced and Detailing.