Seismic response mitigation of prefabricated industrial equipment structural frames through a hybrid isolation system

Abstract

For reducing the excessive acceleration response of the critical equipment in a type of industrial equipment structural frames under strong earthquakes, a hybrid isolation system (HIS), incorporating linear natural rubber (LNR) and lead rubber (LR) bearings, is proposed. The efficiency and reliability of the HIS are verified through a series of full-scale shaking table tests on two prefabricated industrial moment resisting frames (MRFs), with respect to a corresponding fixed-base system (FBS). The structural dynamic characteristic and seismic performance of the two types of MRFs, i.e., reinforced concrete structure (RCS) and composite concrete-filled steel tube structure (CCFSTS), are examined both with the HIS and FBS subjected to a range of seismic intensities. The test results demonstrate the superior performance of the HIS in controlling transient acceleration response under near-fault, far-field and artificial ground motions. The average peak acceleration reduction coefficients (PARCs) of the HIS range between 75.60% and 79.51% in the two considered MRFs along two horizontal directions, with a strict satisfaction on the peak acceleration response for normal operation of the critical equipment. Also, the hysteretic behavior of the HIS is stable and controllable during the earthquake excitations. The peak transient displacement of the HIS is satisfactory, and the residual deformation is negligible even under the maximum considered earthquake (MCE) excitations. Besides, components of the two MRFs are undamaged during the whole test. Thus, with the capacity of protecting the acceleration-sensitive equipment and structural components, the proposed HIS possesses a great prospect in enhancing the structural resilience.