Last reviewed 30 Sept 2026 · 5 min read
Why codes matter
A bridge code is the distilled experience of thousands of bridges — the loads to use, the material properties, the safety factors, the detailing rules and the workmanship standards. Design to the code is a legal and professional requirement, and in exams and interviews the question is usually which code covers which subject, and what design format it uses.
Indian codes for highway bridges — IRC
The Indian Roads Congress (IRC) publishes the codes for road bridges. Some of the main ones:
| Code | Subject |
|---|---|
| IRC:5 | Standard specifications and code of practice for road bridges — general features of design |
| IRC:6 | Loads and load combinations — dead, live (Class A, B, 70R, AA), wind, seismic, temperature, water current, etc. |
| IRC:112 | Code of practice for concrete road bridges (reinforced and prestressed) in limit-state format |
| IRC:22 | Composite construction for road bridges — steel–concrete composite |
| IRC:24 | Steel road bridges |
| IRC:78 | Foundations and substructure |
| IRC:83 | Bearings — metallic, elastomeric, pot, spherical |
| IRC:SP series | Special publications — guidelines for inspection, maintenance, load testing, strengthening, expansion joints, etc. |
IRC codes are revised regularly. The listing above is a guide to which code covers which topic; check the current edition before design and never quote a clause number from memory.
IRC:112 is the main concrete bridge code and replaced the earlier separate codes for reinforced (working stress) and prestressed concrete. It uses the limit state method, with partial safety factors on materials and on loads, serviceability limits (stress, crack width, deflection) and durability requirements by exposure class.
Indian Railways codes
Railway bridges follow the Indian Railways Bridge Rules (loading, deflection and design stresses) and a family of IRS codes (Indian Railway Standard):
- IRS Bridge Rules — the rules specifying the loads (standard loading, dynamic augment, forces) and the general principles.
- IRS Concrete Bridge Code — design of reinforced and prestressed concrete bridges.
- IRS Steel Bridge Code — steel bridges; welded and bolted design.
- IRS Bridge Substructure and Foundation Code — piers, abutments, foundations.
- Indian Railways Bridge Manual — inspection, maintenance and rehabilitation practice.
- Schedule of Dimensions — moving and fixed dimensions that define clearance requirements.
- RDSO (Research Designs and Standards Organisation) publishes the standard drawings, guidelines and technical specifications for bridges, bearings, girders, and instrumentation.