STATIC AND DYNAMIC BEHAVIOUR OF MULTI STOREYED BUILDINGS CONSIDERING FINITE WIDTH OF JOINTS AND VARIABLE STIFFNESS OF GIRDERS

Abstract

In order to analyse a multistorey frame against static and dynamic' forces, centre to centre dimensions of beams and columns are usually taken irrespective to their size, whereas in practice, all frame members have finite cross-sections. When the depth of the cross-section is significant as in the case of wide columns and beams, accuracy of analysis can be improved and savings can be effected in design, if the finite size of joints is taken into account. The nn ltistorey frames of 1,2,3,6 and 10 storeys are analysed considering finite width of joints and on the basis of centre line dimensions, it is observed that lateral deflection, interstorey drift, time-period and member forces are reduced on consideration of finite width of joints. In addition to this, the validity of assumption-"floor beam behaves as a T-beam" , is tested by introducing intentionally varrying stiffness i.e. rectangular beam at either. end and T-beam at the central portion. All the characteristics viz deflction, inter storey drift, time-period etc. get increased where as the design governing forces are seen to be reduced in the later case . The assumption of T-beam is found on the conservative side.