Evaluation of Seismic Acceleration Demands on Mechanical Support Systems

Earthquakes are among the most influential force of nature that affect human life. Reconnaissance after the severe earthquakes pointed out that seismic performance of non-structural members and elements could be as significant as the structural members in lateral force-resisting systems. As such, it is important for design engineers to recognize the seismic demand on the mechanical systems that support the critical non-structural components (e.g., sprinklers, electrical and mechanical equipment, etc.) in terms of the safety during and after an earthquake as well as functionality and retrofitting cost after an earthquake. The primary goal of this study is to systematically investigate the seismic demands on the mechanical support systems of a typical mid-rise steel structure. For this purpose, non-linear time history analyses are carried out using a suite of ground motion acceleration records to evaluate the seismic demands on both seismic force-resisting system and the support system by means of inter-story drift angle and horizontal accelerations, respectively. Results obtained from the analyses are discussed considering the requirements stipulated in the current national and international buildings and recommendations are made.