Experimental simulation of base‐isolated buildings pounding against moat wall and effects on superstructure response

Abstract

SUMMARY Base‐isolated buildings are typically important facilities expected to remain functional after a major earthquake. However, their behavior under extreme ground shaking is not well understood. A series of earthquake simulator experiments were performed to assess performance limit states of seismically isolated buildings under strong ground motions, including pounding against a moat wall. The test setup consists of a quarter scale three‐story frame isolated at the base with friction pendulum bearings and a moat wall model. An effort was made to properly scale the strength and the stiffness of the frame relative to the bearings properties from a professionally designed isolated three‐story steel intermediate moment‐resisting frame so that realistic yielding mechanisms can be observed. The moat wall was modeled as either a rigid triangle steel stopper or a concrete wall of various thicknesses with soil backfill. The moat wall gap was set to various displacement increments to examine the sensitivity of this parameter and also to assess the effects of impact on the superstructure at different velocities. The test results indicate that the contact forces are largely dependent on the gap distance, impact velocity and wall flexibility and, in extreme cases, pounding can induce yielding in the superstructure. Copyright © 2012 John Wiley & Sons, Ltd.

Performance of base‐isolated reinforced concrete buildings under bidirectional seismic excitation considering pounding with retaining walls including friction effects

“…Furthermore, column curvature ductility at the first story reaches a maximum value of 19, which is greater than the minimum curvature ductility capacity of 15, and is close to the maximum curvature ductility capacity of 24, also indicating that the first story is near collapse (Figure 10(h)). Note that such a dramatic increase in base-level acceleration because of pounding was also reported by Masroor and Mosqueda [8] based on recent shaking table tests. This further highlights high concentration of the adverse effects of pounding only at the first story.…”

“…Because pounding of base-isolated buildings with adjacent structures is likely due to large base displacements, several investigations have been carried out through numerical analyses [1][2][3][4][5][6][7] and experimental studies [8,9]. Because pounding of base-isolated buildings with adjacent structures is likely due to large base displacements, several investigations have been carried out through numerical analyses [1][2][3][4][5][6][7] and experimental studies [8,9].…”

Effect of Ground Motion Directionality on Seismic Response of Base-Isolated Buildings Considering Pounding to Adjacent Structures

“…A number of recent research works that extend the simulation in the more realistic 3D space [10][11][12][13][14][15][16][17][18][19] have been reported. Matsagar and Jangid [10] investigated the seismic response of a single-story asymmetric structure supported on various base-isolation systems during impact with adjacent structures.…”

Computer-aided investigation of special issues of the response of seismically isolated buildings

“…In practice, there is a possibility of structural pounding of seismically isolated buildings with adjacent structures during very strong earthquakes, mostly due to the large relative displacements at the isolation level, when the width of the clearance that is provided around a seismically isolated building is limited by practical constraints. Although earthquakeinduced pounding incidences between fixed-supported buildings motivated relevant research, very limited research work has been carried out for structural pounding of seismically isolated buildings [5][6][7][8], which exhibit quite different dynamic characteristics from conventionally fixed-supported buildings. Selected results are presented from assessing the influence of structural pounding of a base-isolated building with the surrounding moat wall or adjacent structures on the effectiveness of seismic isolation.…”