Assessment of building behavior under near-fault pulse-like ground motions through simplified models

Abstract

Interstory drift and floor acceleration demands in buildings subjected to near-fault pulse-like ground motions are investigated by means of simplified building and ground motion models. A pulse model proposed by Mavroeidis and Papageorgiou is used to represent near-fault ground motions. Similarly, a continuous model formed by a flexural beam laterally coupled to a shear beam is used as a simplified model of multi-story buildings. Firstly, closed-form solutions for the response of damped single-degree-of-freedom systems subjected to Mavroeidis Papageorgiou (MP) pulses are derived and employed to construct closed-form solutions for the response of the simplified continuous model. This allows the analysis of elastic and near elastic response of buildings, which is important for the assessment of financial losses on non-structural elements. Peak responses of the continuous systems subjected to MP pulses are compared to those of the continuous systems subjected to recorded near-fault pulse-like ground motions. It is found that the proposed closed-form solutions produce very good estimates of peak interstory drift demands as well as their variation along building height. Acceleration demands are found to be more sensitive to the high frequency content of the ground motion, therefore, the results are not as good, but still MP pulses are able to capture the main features of the response when a sufficient number of modes is considered. After several parametric studies it was found that pulse duration is the most critical parameter influencing floor acceleration and interstory drift demands, when near-fault pulse like ground motion occurs; as it can induce large variations on peak and along height acceleration and drift responses.