Investigation of forward directivity effects on design spectra of industrial complexes near Assaluyeh fault

Recorded ground motions in near-fault region have completely distinct nature from others that recorded in far field of the fault. Near source outcomes cause much of the seismic energy to appear in a single large and long period pulse at the beginning of the velocity record. Assaluyeh complex is located near the reverse Assaluyeh fault that is a segment of Mountain Front Fault. This complex contains facilities which have a wide range of structural periods. Effects of this vicinity on the seismic hazard of this region can be considered by using approaches which incorporate effects of near-fault in seismic hazard analysis. It can be achieved by using near source specific ground motion models in probabilistic seismic hazard analysis and using accelerograms which contain the pulse-like effects of forwarding directivity. The results indicate that the site-specific design spectra of this study fall at an upper level in comparison with the standard design spectra of Iranian Code of Practice for Seismic Resistant Design of Buildings (Standard No.2800) and the site-specific design spectrum of International Institute of Earthquake Engineering and Seismology (IIEES). It is worth noting that near-fault effects should be considered in probabilistic seismic hazard analysis and preparation of site-specific design spectra if the site is located near source region of a fault.