IMPACT OF SEISMIC PROVISIONS IN DIFFERENT EDITIONS OF THE EGYPTIAN CODE OF LOADS

Abstract

The last edition of the Egyptian Code of Loads (ECOL) was released by the end of year 2008. The seismic provisions in this edition are almost completely different compared with those in the 1993 edition while some specific changes are presented relative to the 2003 edition. The major significant changes in the seismic provisions revealed in the different editions are reviewed. The impact of these provisions on the level of seismic protection for different types of structures with different heights is analyzed and discussed. An analytical analysis is carried out to compare and verify the applicability of these methods and the protection level they introduce. The modal response spectrum (MRS) analysis is carried out using the elastic design spectrum specified by the 2008 ECOL while the time history analysis (THA) is applied using seven different real earthquake excitations selected to match the specified elastic spectrum and soil type. Suggestion to rationally enhance the seismic protection level obtained from the multiple response spectrum is presented and emphasized. This study extends to analyze and compare our seismic provisions with those appeared in different international codes for sites with similar conditions. It is found that the provisions in the 1993 edition yield base shear much less than the values obtained using 2008 edition especially for low to medium height buildings located in medium and high seismic zones. Also, it is found that some provisions in the new edition need to be urgently reconsidered.