Assessment of important seismic provisions of EBCS 8 - 1995 from structural dynamics perspective

Abstract

In this paper, an attempt is made to assess some of the important seismic provisions and speciflcations of the 1995 Ethiopian Building Code Standard (EBCS 8) from, the perspective of the theory of structural dynamics and principles of earthquake engineering. For this purpose, a concise but thorough theoretical background is provided on the vibration of structural systems. Only horizontal earthquake excitation of the systems is treated, as this causes the most important effects on building structures. Many concepts that are unknown to the average structural designer, but specified by the Code for strict adherence are clarified and critically assessed. The design spectra of the Code are compared with early research results that served as the basis for the preparation of design spectra of many international codes. Existing discrepancies are shown and illustrated using an example problem. Important conclusions are drawn and some recommendations made. Comparison of the provisions of the Code with those of other international codes is not the intention of the paper. This is postponed to a future work.

Keywords: single-degree-of-freedom-system (SDOF), multi-degree-of-freedom-System (MDOF), generalized-single-degree-of-freedom-system (GSDOF), response spectrum, design spectrum, time-history analysis (THA), response-spectrum analysis (RSA), tripartite plot, Rayleigh quotient, story drift.