Response of frames seismically protected with passive systems in near-field areas

The present paper analyses the behaviour of moment resisting frames in reinforced concrete subject to earthquakes recorded in near-field areas. In these areas, the signals show impulsive-type accelerograms, with velocity and displacement peaks higher than in far-field zones especially for the fault-normal component of the ground motion velocity in the direction of propagation of the wave, which shows large-amplitude pulses. In the following, seven near-field signals scaled in agreement with the design spectrum of the Italian code (NTC, 2008) have been adopted to perform a nonlinear analysis on a six-story frame. The response has also been determined for the same frame protected once with hysteretic-type energy dissipaters and once with base isolators. The aim of the present study is to acquire quantitative knowledge on the near-field ground motion effects on frame buildings and on their damage also in the presence of passive seismic protection systems