Elastic Earthquake Response of Building Frames

The accuracy of the response spectrum analysis (RSA) for estimating the maximum response of a building directly from the earthquake design spectrum is evaluated with the objective of developing better simplified analysis procedures which are suitable for preliminary design of buildings. The procedures can also be included in building codes. This paper demonstrates that: (1) For a fixed fundamental period $T_1$ of the building, the response contributions of the higher vibration modes increase, and consequently, the errors in the RSA results increase, with decreasing beam‐to‐column sitffness ratio ρ; (2) for a fixed ρ, the response contributions of the higher vibration modes increase, and consequently, the errors in the RSA results increase, with increasing $T_1$ in the medium‐ and long‐period regions of the design spectrum; and (3) the RSA results are accurate enough for design applications. Based on the results presented in this paper, improved simplified analysis procedures for the preliminary design of buildings are developed in the companion paper.