Seismic Vulnerability of Rc Shell And Spatial Structures

Abstract

This study deals with seismic behaviour of reinforced concrete shell and spatial structures under static and dynamic loads. IS: 2210-1988, Criteria for Design of RC Shell Structures and Folded plates, suggests to design shell structures for seismic loads in accordance with IS 1893 (Part-1):2002, Criteria for earthquake resistant design of structures, however lack in detail specifications for shell structures to be adopted. Therefore, from this point of view, a methodology needs to be proposed for understanding the behaviour of shell structures under seismic loads. Linear static and dynamic analyses are performed on the basis of IS 1893(Part-1):2002 using SAP-2000 software. The Equivalent Static method is performed for 63 load combinations and the Response spectrum method is performed for 151 load combinations. newline newlineIt needs to be studied whether nonlinear analysis is applicable for reinforced concrete shell structures or not. In this study, nonlinear static analysis and nonlinear dynamic analysis of cylindrical shell structure are attempted. SAP-2000 finite element software is used to perform both analyses. newline newlineAn attempt has been made for seismic vulnerability assessment of reinforced concrete cylindrical shell structure using nonlinear static and dynamic procedures. Conversion of MDOF model of reinforced concrete shell structures into ESDOF model is done using concept of N2-method suggested by Fajfar with some modifications. For nonlinear static analysis SAP 2000 software is used and for nonlinear dynamic analysis NONLIN computer program is used. Nonlinear time-history analyses of ESDOF model are performed with a suite of 20 ground motions used by Vamvatsikos and Cornell (2002) scaled to different levels of intensity. A computer program NONLIN is used to perform Incremental Dynamic Analysis. Maximum displacement obtained from time-history analyses are plotted against ground motion intensities. Yield and collapse capacities of the structure are determined using IDA curves.