40 Sets of Strong Ground Motion Records Convey All Design Response Spectrums Located in Tartous, Syria

Selecting  seismic  records  in  Global  Standards is, until  now,  based  on  matching  design response  spectrum,  where  records  should  have  seismological  characteristics  similar  to  the expected earthquake for the considered site (magnitude, distance, fault mechanism and soil conditions). Then it is necessary to scale these records to match the intensity of the earthquake expected for the site.  Generally,  scaling  can  be  made  by  ground  motions  uniform scaling  in  time domain to best match (in average) the target spectrum within a period range of interest. Design ground motions are typically prescribed by smooth response spectra.  But it is preferred to use a set of time histories that are representative of the design target spectrum in an ensemble average due to the increase of available strong ground motion database and improving computing power.

When testing the selected and scaled ground motions, it’s a standard procedure to use the nonlinear time history analysis to validate the results in terms of structural responses and their variation. This proves the efficiency of the presented procedure. In  this  study,  basic  methodologies  for  selecting  and  scaling  strong  ground  motion  time histories  are summarized  and  utilized  to  obtain  40  sets  of  real  seismic  records  that  are sufficient  to  Tartous  city’s  needs.  These  sites  are  conveying  a  wide  range  of  classic buildings periods, and all soil types Sa, Sb, Sc, Sd and Se, which means the city’s five design spectra.  Thus the Syrian  engineer  can  safely  use  these  records  in  linear  and  nonlinear analyses recommended for design and research purposes. Then a sample of five resulting time histories are investigated and compared in terms of suitability as input to time history analysis of civil engineering structures, by means of time history analyses of SDOF systems, which are conducted to examine the scatter in the structural response. The nonlinear response of SDOF systems is represented by bilinear hysteretic model. Assuming 5 different Periods, yield strength reduction factor, R= 4.5, α=3% post-yield stiffness, a number of 350 runs of analysis are conducted. The results are described for elastic displacement D.