Response Parameters of Steel Midrise Buildings with Dual Structural Systems subjected to Near Field Records contain Coherent Velocity Pulses

The seismic design of structures located close to active faults must account for the special characteristics of ground motions in the near-fault region. These ground motions can be more severe than far-fault ground motions. Studies on recorded near fault strong motions indicate that there are usually some obvious effects in the acceleration, velocity and displacement time histories. Generally, the strong ground motions recorded in near fault zones are contain coherent pulses in the velocity time history. The structural demand due to an earthquake ground motion can be approximated by performing nonlinear time history analyses with computational models subject to a given ground motion. In midrise to highrise structures, dual systems (DS) enable a structural designer to satisfy the stringent drift limitations of current codes without compromising ductility. The resistance system against lateral loads is braced frame + moment resistant frame in all models. In this study the performance of 3 models midrise buildings has been assessed by conducting nonlinear time history analyses. The performances of the structures are analyzed by using Sap2000. It was found that the response of structures to near-fault ground motion is substantially different from the response to far-field earthquake records. According to the nonlinear analyses, the structural demands which are calculated subject to near field records are considerably more than those due to far field motions. The nonlinear time history analyses results indicate that dual structural system has appropriate seismic behaviour in midrise buildings.

Keywords:

Dual systems , Near-fault , Far-fault , Nonlinear time history analyses , Midrise buildings , highrise structure