Non Linear Analysis of High-Rise Buildings under Earthquake Loads

Abstract

In this research, the structural systems normally used in tall buildings are presented. The linear and non linear finite element analysis of tall building under seismic loads is carried out .The main purpose was to study the importance of nonlinear analysis for displacement and shear force. A selected tall building of reinforced concrete skeleton having height of 20 stories was checked by increasing the number of nodes(one node and two nodes ) in the corner columns and compared the carve of the displacement, then have been analysed and designed .Dead load, live load, and seismic load were applied to the selected buildings in accordance to BS 8110-1:1997. The selected building were analyzed using the finite element structural analysis program ETABS in linear and non linear mode for any load alone and for all loads together. The results obtained ( the maximum displacement in linear analysis 53.5mm ,in P_Δ case 83.4 and P_Δplus larg displacement 85.6 also the maximum shear force were 395.8Kn,641.8Kn and 900.9Kn respectively ) were analysed and discussed . These clearly show the necessity of non linear analysis of real displacements are required and the importance of the P_∆ plus large displacement analysis if the correct shear forces are to be obtained