Title: Effect of vertical ground motion on the response of structures isolated with friction pendulum isolators
Authors: Huseyin Cilsalar; Michael C. Constantinou
Addresses: Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA ' Department of Civil, Structural and Environmental Engineering, University at Buffalo, The State University of New York, Buffalo, NY, 14260, USA
Abstract: Structures isolated with friction pendulum isolators have their instantaneous stiffness and friction force dependent on vertical load. As such they are affected by vertical ground motion. This paper presents a study to investigate the vertical earthquake effects on the base shear force and isolator displacement in structures equipped with friction pendulum isolators and with or without added viscous damping devices in the isolation system. Analyses are carried out for a simple rigid structure and results are presented for values of the ratio of the base shear and isolator displacement calculated with the effect of the vertical ground motion and divided by the same quantity when the vertical ground motion effect is disregarded. The effects of two-component horizontal ground motion are also studied. The results may be used to modify the equivalent lateral force method of ASCE 7 for seismic isolated structures in order to account for the vertical earthquake effects.
Keywords: vertical ground motion; friction pendulum isolators; dampers; seismic isolation; sliding bearings; base shear; isolator displacement.
International Journal of Earthquake and Impact Engineering, 2017 Vol.2 No.2, pp.135 - 157
Received: 01 May 2017
Accepted: 15 Jun 2017
Published online: 04 Jan 2018 *