Journal of the Arab American University مجلة الجامعة العربية الامريكية للبحوث

Journal of the Arab American University  مجلة الجامعة العربية الامريكية للبحوث


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.