Notes on the Structural Response Parameters under Iranian Pulse Like Strong Near-Field Records of Tabas 1978 and Bam 2003

This paper is devoted to studying the most important characteristics of two earthquake disasters in Iran, Tabas 1978 and Bam 2003 from engineering seismological and structural engineering points of view. Iran as one of the world’s most earthquake prone countries, has been exposed to many destructive earthquakes in the past long years. In this research, the most important physical characteristics of a strong record such as acceleration, velocity and displacement time history, frequency content, energy flux are studied and then assessment of their influence on the tall buildings with framed tube skeletons are performed. Four 15 and 30 story structural models with separated framed tube based skeletons were selected and designed. The structural models have been designed according to the Iranian seismic code 2800 (4th edition). The structural response parameters have been computed and obtained by conducting a number of non-linear dynamic time history analyses under three-component strong records. Based on nonlinear analyses, the values of maximum story acceleration and displacement time history, configuration of plastic hinge, were investigated and the results have been discussed and compared with the life safety and collapse prevention performance limits, as recommended by Fema 356 and Fema 440. Findings from this study reveal that, mean maximum demands and the dispersion in the peak values were extremely higher subjected to the powerful near-fault records such as Tabas 1978 and Bam 2003. As a general note, it was concluded that the seismic response parameters of 15 story steel framed tube structures are intensively influenced by those strong earthquake records which contain powerful forward directivity effects and are able to emerge long period pulses in their time histories.

کلیدواژه ها:

Non-Linear Dynamics ، Framed Tube Skeleton ، Strong Ground Motion ، Velocity Pulse