MATHEMATICAL MODELLING FOR THE SEISMIC ANALYSIS OF FRAMED BUILDINGS

Abstract

The results of dynamic analysis, are influenced by the approximations involvad in establishment of Mathematical mod~'ls. The importance of mathematical modelling has been recognized by earthquake engineers in the past however, the concentration has been on giving results of a particular chosen modelling technique rather than on the implication of idealizations carried out in mathematical modelling. All structural problems are truely three dimensional in nature and have to be analysed as such. Three dimensional analysis is complicated and expensive. Therefore modelling for earthquake analysis of multistorey frame buildings has to bo simplifid while maintaining the three dimensional nature of the problem. This dissertation examines the effiCacy of one dimensional; two dimensional, and three dimensional models using different modelling tt-chn ques.' The dissertation also studies modelling for floor slabs by incorporating their stiffness in beams. The study indicates that all one dimensional models give highly conservetiva results. For symmetric frames a two dimensional model in which frames are arranged side •by side arid conne=cted by inextensible pin—ended members is found to give excellent results. For unsumm :tric frames use of three dimensional models is recommended. d. Thy: study also revels that incorporation of floors stiffn:ssos by including them in b'ams stiffnesses is adequate.