Evaluation of local soil site class effects on the behavior of a special moment resisting steel frame with the use of 1989 Loma Prieta earthquake records

The Fa and Fv factors which are used to consider the local site class effects in American seismic design codes are calibrated with the use of the seismic data recorded during 1989 Loma Prieata Earthquake. This calibration process was carried out via the elastic and inelastic spectral analyses of Single Degree of Freedom (SDOF) systems. Since the number of recordings of this earthquake are too many, it can be accepted as a rich data base in order to examine the soil site class effects. In this sense, a ten story special moment resisting frame is designed according to the American design codes and inelastic time history analyses of this model building is carried out under the effect of the whole recordings of the 1989 Loma Prieta Earthquake. The main purpose of this work is to examine the generalizations constructed based on SDOF systems for a multi story model frame. Initially, multiple regression analyses were performed with independent parameters of closest distance from the fault rupture and ground motion shear wave velocity whereas dependent variable was the structural response. For none of the structural response parameters, the correlation was acceptable. Thus, in order to represent a certain magnitude-distance scenario, which in turn means to represent a homogenous seismic hazard zone, the results are grouped in 10 km intervals. The relations between the roof displacement-shear wave velocity and base shear force-shear wave velocity are evaluated. Obtained results do not indicate a characteristics systematic increase (/decrease) relationship. However, the only certain result is that, for small shear wave velocity values the dispersion of the structural response parameters are considerably high. Keywords: Steel Frame, Local Site Class Effects, 1989 Loma Prieta Earthquake Records