Civil Engineering Association

STEPS FOR SAFE DESIGN AND CONSTRUCTION OF MULTISTOREY REINFORCED CONCRETE BUILDINGS

A large number of reinforced concrete multistoreyed frame buildings were heavily damaged and many of them collapsed completely in Bhuj earthquake of 2001 in the towns of Kachchh District (viz., Bhuj, Bhachao, Anjar, Gandhidham and Rapar) and other district towns including Surat and Ahmedabad. In Ahmedabad alone situated at more than 250 kilometers away from the Epicentre of the earthquake, 69 buildings collapsed killing about 700 persons. Earlier, in the earthquake at Kobe (Japan 1995) large number of multistoreyed RC frame buildings of pre 1981 code based design were severely damaged due to various deficiencies. Such behaviour is normally unexpected of RC frame buildings in MSK Intensity VIII and VII areas as happened in Kachchh earthquake of January 26, 2001. The aim of this paper is to bring out the main contributing factors which lead to poor performance during the earthquake and to make recommendations which should be taken into account in designing the multistoreyed reinforced concrete buildings so as to achieve their adequate safe behaviour under future earthquakes. The Indian Standard Code IS:1893 was suitably updated in 2002 so as to address the various design issues brought out in the earthquake behaviour of the RC Buildings. The paper highlights the main provisions of this code.