Longer Version of Seismic Clause, which might be brought out as “Guidelines for Seismic Design of Highway Bridges” in line with similar AASHTO publication is one of the present mandates of the IRC committee. Towards this, Guidelines are proposed comprising of various chapters on (a) Design Philosophy; (b) Design Methods; (c) Detailing etc., besides introducing an Explanatory Handbook for use by designers.
8.
of practice for road bridges (Section II) (second revision) - loads & stresses’, Indian Roads Congress, New Delhi 4.
IRC-6 (1966). ‘Standard specification and code of practice for road bridges (Section II) (third revision) - loads & stresses’, Indian Roads Congress, New Delhi
5.
IRC-6 (2010).‘Standard specification and code of practice for road bridges (section ii) (fifth revision) - loads & stresses’, Indian Roads Congress, New Delhi
6.
IRC-6 (2014). ‘Standard specification and code of practice for road bridges (Section II) - loads & stresses (revised edition)’, Indian Roads Congress, New Delhi
7.
BRIDGE RULES (1941). ‘Bridge Rules’, Ministry of Railways, New Delhi
8.
IITK-RDSO GUIDELINES (2010). ‘IITK RDSO guidelines on seismic design of railway bridges: provisions with commentary and explanatory examples’, RDSO, Lucknow.
9.
IS 1893 (1984)‘Criteria for earthquake resistant design of structures (fourth revision)’, Bureau of Indian Standards, New Delhi
Conclusions
Seismic provisions of first IRC Bridge Code, published in the year 1958 have undergone significant modifications during the last five decades. Continuous revision of the Seismic Clauses in IRC: 6 has been necessary to bring up the same at par with International Standards and also conforming to the Limit State Method of design adopted in the IRC Concrete Bridge Code IRC: 112-2011 and relevant BIS publication IS: 1893 – Part 3. The major aspects covered in the latest IRC: 6-2014 pertain to inclusion of appropriate map of seismic zones, as per IS 1893, introduction of Response Reduction factor, Importance Factors, Limit State Method of design and provision for Ductile Detailing etc. IRC is expected to finalize the Longer Version of Seismic Clause in the form of detailed Guidelines in near future. Evolution of seismic provisions for railway bridges since its first publication (1941) and first revision (1964) to publication of RDSO guidelines (2015) for seismic design of railway bridges has been substantial. As things stand today, there are significant variations in seismic provisions for bridges in IS 1893, IRC 6 and Railway codes, which needs to be narrowed down.
9.
References
1.
IS 1893-Part 1 (2002).‘Criteria for earthquake resistant design of structures: Part-1,general provisions and buildings (fifth revision)’, Bureau of Indian Standards, New Delhi
2.
IRC-6 (1958).‘Standard specification and code of practice for road bridges (Section II) - loads & stresses’, Indian Roads Congress, New Delhi.
3.
IRC-6 (1964). ‘Standard specification and code
The Bridge and Structural Engineer
10. Paper No.112 (1946). ‘Standard specification and code of practice for road bridges (Section II)’, Journal of IRC, Vol X. 11. IRC-78 (1980). ‘Standard specification and code of practice for road bridges (Section VII) (First Published) – Foundations & Substructure’, Indian Roads Congress, New Delhi 12. BRIDGE RULES (1964). ‘Bridge Rules’, Ministry of Railways, New Delhi 13. RDSO GUIDELINES (2015). ‘RDSO Guidelines on seismic design of railway bridges, published by bridge & structures directorate’, RDSO, Lucknow. 14. IS 1893-Part 3 (2014). ‘Criteria for Earthquake Resistant Design of Structures; Part-3 Bridges & Retaining Walls’, Bureau of Indian Standards, New Delhi
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