INVESTIGATION OF DIRECTIVITY EFFECTS OF NEAR -FAULT RECORDS ON THE RESPONSE OF JACKET PLATFORMS

Earthquake records in sites within distance of less than 20 km from a ruptured fault are significantly influenced by the rupture mechanism the direction of rupture propagation relative to the site and possible permanent ground displacements resulting from the fault slip and have different specifications such as high frequency content directivity and fling step . directivity causes the internse pulse of the record leading to sever damages. steel jacket platforms are the special structures with long natural period . this period is in the range of pulse period of near -fault earthquakes. this paper presents the effects of near-fault earthquakes on the behavior of steel jacket platforms.

Keywords:

near-fault earthquakes , directivity , mathematical pulse model , steel jacket platforms.