SEISMIC ANALYSIS OF A CHIMNEY

Abstract

Seismic analysis of chimneys is currently performed using finite element approaches combined with probability theory methods. This article presents the results of a seismic analysis of a chimney computational model (CCM) using ground motion accelerograms. Based on time-domain analysis theory, a mathematical model of chimney vibrations, considered as a discrete dissipative system (DDS), is constructed. Within this model, the differential equations of motion are reduced to a system of 2n algebraic equations of recurrent form, where n is the number of degrees of freedom. In the reaction equations, the displacements and velocities at the current step of the digitized accelerogram are determined based on the values of these same parameters at the previous step, which are taken as initial conditions. The energy dissipation effect is taken into account using a non-proportional damping model. An analysis of the seismic vi-brations of a reinforced concrete RMDT at n = 100 is presented using the accelerogram of the Iranian earthquake (1978). The dynamic response parameters of the chimney are obtained, and the accuracy of the dynamic problem solution is assessed.