Effect of Design and Detailing Deficiencies on Seismic Performance and Vulnerability of Indian RC Frame Building
Due to rapid increase in demand of residential and commercial buildings in India, there is a steep increase in land prices, which is leading to compulsory usage of maximum land and giving birth to irregular shapes of multistorey buildings. Further, in Indian multi-storey buildings, parking is a major problem. Professional consultants/ architects find an easy solution for parking by providing open ground storey; however, the other storeys of these multistorey buildings are infilled with masonry panels. Other problems are typically the re-entrant corners to provide ventilation in these buildings, insufficient seismic gap between two building blocks and asymmetric distribution of mass, stiffness and strength creating torsion irregularity. Along with these configurational deficiencies, there are a lot of design, detailing and constructional deficiencies. To have an overview of the prevailing design and construction practices in India, a survey of multistory buildings was conducted in the New Okhla Industrial Development Authority (NOIDA) Township in the national capital region (NCR). NOIDA is one of the fastest growing cities of the world and the largest existing planned industrial township of Asia. About 50 randomly selected multistoried RC frame buildings have been surveyed. The survey was based on visual inspection using a questionnaire. In some cases, access was available to structural drawings, but in most of the cases, structural configuration was plotted at site and typical member sizes were measured. It has been found that most of these building lacks and even voilets the basic seismic resistant provisions. It was found that the surveyed buildings do not have one but a combination of several deficiencies. Simplified Vulnerability Assessment (SVA) of buildings was conducted as per the procedure of FEMA-310 (1998). The observed deficiencies have been broadly classified into two groups, ‘Configurational’ deficiencies and ‘Design and Detailing’ deficiencies. The detail of common deficiencies observed during survey has been discussed in the paper. The seismic performance and vulnerability of RC buildings with the most common design and detailing deficiencies have been estimated.