Shaking table test of a timber building equipped with a novel cost-effective, impact-resilient seismic isolation system

Abstract

In most cases, construction of Light Frame Timber Buildings (LFTBs) in areas of high seismic hazard requires strong wood frame shear walls and continuous rod systems, which increases the cost of LFTBs. Frictional seismic isolation might be applied to protect LFTBs against extreme ground motions and mitigate the cost of continuous rod systems. However, there are no experimental studies on the response of LFTBs equipped with frictional isolation and subjected to extreme seismic ground motions that might cause impacts between the slider and the perimetral ring or between the isolated base and the perimetral moat wall. This study explores the potential of using impact-resilient frictional isolators as a feasible solution to alleviate stiffening and overturning costs of LFTBs while making them resilient to impacts in case of extreme events. This issue has been researched by evaluating the response of a 1:2 scaled 3-story LFTB isolated with a novel Impact Resilient Double Concave Frictional Pendulum recently developed by the authors. The specimen was subjected to a suite of shaking table tests (white noise, harmonics signals, and seismic records), including strong ground motions such as the Concepcion record (2010 Maule, Chile earthquake, Mw = 8.8) scaled to 130 %. Results indicate that despite being subjected to extreme excitations, peak acceleration ratios (i.e., the ratio of peak floor acceleration to peak ground acceleration) did not exceed 0.75, and story drift ratios were smaller than 0.52 % in most cases. Thus, the superstructure remained in the elastic range without damage. The study demonstrates the potential of achieving effective seismic protection of LFTBs using Impact Resilient devices. In addition, this paper presents a numerical model developed with experimental data, which provides insight into modeling issues such as, for instance, damping properties.