Conference Papers
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Item Effect of diaphragm discontinuity on the seismic response of an rc building(Springer Science and Business Media Deutschland GmbH, 2021) Mable Vas, V.; Nagaraja, P.; Venkataramana, K.Although rigid floor diaphragm is a reasonable assumption for seismic analysis, certain building configurations may exhibit diaphragm flexibility. Detailed investigations have been carried out on modelling of flexible diaphragms compliant with various codes such as ASCE-07 and UBC 1997. Studies have shown that diaphragm flexibility amplifies both the deformation and the shear in the diaphragm. However, additional studies are essential to assess the magnitude of such amplification and to account for it in the design. The methodology is outlined by three major elements such as the choice of building models, the adopted method of analysis and the parameters studied. Buildings with large cut-outs and openings are observed to exhibit flexible behaviour. These models are analysed dynamically using a site-specific response spectrum developed from probabilistic seismic hazard analysis (PSHA) for Mangalore region (a coastal city in Karnataka, Southern India). The analysis is carried out using a G+10 RC building. The effect of percentage of openings in the diaphragm is studied using structural parameters such as storey drift, base shear and storey displacement with the help of ETABS 2015 software, and the optimum shape for these openings in a building plan is finalized. Further, time history analysis is performed over the models, and the results obtained through response spectrum and time history analysis are compared. The study highlights the importance of diaphragm flexibility in determining the seismic response of a building. This flexibility causes significant increase in the building period, which results in reduction in the earthquake-induced base shear. Since the seismic input used for the study was developed for the moderate seismic zone, the outcomes of this investigation are believed to have vast applications. © Springer Nature Singapore Pte Ltd 2021.Item Seismic Analysis of a PSC I Girder Bridge Using Nonlinear Static Method(Springer Science and Business Media Deutschland GmbH, 2023) Vamsi, A.; Baby, B.; Palanisamy, T.This paper presents a seismic analysis of three spanned Prestressed Concrete (PSC) I girder bridge, which is known for having a high load-bearing capacity and high flexural resistance. Bridge modeling is done in MIDAS Civil software. MIDAS Civil is a recently developed finite element-based software, exclusively for bridge modeling and well known for its user-friendly interface. A case study was carried on a 36.7 m of three spanned prestressed I girder bridge which consists of 4 numbers of Pre-Cast Post Tensioned-I Girder of 35.7 m long, under seismic Zone-II and is rested on hard soil strata. Loading on the superstructure is assigned as per IRC:6-2017. The entire work is divided into two phases; in the first phase, a three-dimension model of the bridge has been subjected to the linear dynamic method (response spectrum method) to obtain the displacement demand of the bridge. In the second phase, the nonlinear static method (push-over analysis) has been performed as per ACT 40 and FEMA 440. The displacement capacity results from the push-over analysis are used for carrying out seismic performance evaluation of a bridge. After analysis, the seismic response of a bridge is found out in terms of base shear and displacements. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.