Site effect and soil non-linear behavior in frequency domain in Northern region of Yazd city
Subject Areas :
Ahmad Adib
1
(
دانشگاه آزاد اسلامی واحد تهران جنوب
)
Keywords: Yazd, Site effect, non-linear behavior,
Abstract :
In this research, ground motion analysis and site effect were conducted in the north of Yazdcity using data from boreholes and accelerographs with regard to changes in frequency. Toestimate the soil non-elastic response and equivalent linear behavior of soil, an iterativeloop was utilized. The first iteration was performed using shear modulus and attenuationratio with regard to the incoming stress-strain curves. The test was frequently repeated inorder to comply with the determined numerical requirement. Vibrations with the mostcritical resonance response were assumed as the highest probable damage mode in the area.To evaluate site effect in the north region of Yazd city, geotechnical data, down holeseismic profiles and historical seismic records of the region were used. The accelerationrecords of ground motion in bedrock for a 100 years return period in Shahediyeh andAmirabad boreholes that are used for this resarch work are 0.151g and 0.157g,respectively . Taking the above mentioned return period into consideration, for Shahediyehborehole the vaiues of resonance frequency and alluvium resonance ratio were measured as5.4 and 1.6, respectively. Similarly, for Amirabad borehole, these values are 5.8 and 1.7,respectively. On the basis of average resonance ratios and frequencies obtained from all themodels, the amplification of shear waves are intensified in frequencies between 5 to 6 Hzwith a resonance ratio of 1.6
