An Approximate Method for Modal Analysis of Dynamic Structures

Abstract

This research is to study an approximate modal analysis of multistory building. The higher mode effects will be considered, depend on a lateral load pattern and frequency domain of loading. An analysis of dynamic responses of tall building used much time, much memory consumption of computer and increased accuracy no much. The method of modal analysis of dynamic structure is based on the concept that the total response may be obtained from the contributions of equivalent single-degree-offreedom modal systems, in combination with the technique of modal superposition. An approximate modal analysis method is a
sum response of the first three translation modes of each building. This study is to investigate the performance of the method. An example of this study is five story building modeled by five degree of freedom load by periodic force vary in frequency domain and a lateral load pattern. Numerical method used Newmark method. The results of the proposed method are more accuracy
than the other approximate methods.