Development of a bidirectional rocking isolation bearing system (Bi‐RIBS) to control excessive seismic response of bridge structures

Abstract

A bidirectional rocking isolation bearing system (Bi-RIBS) is proposed to provide seismic protection for bridge structures. By using the 3-D rocking motion of the Bi-RIBS, this system acts as a mechanical fuse to limit the maximum force transmitted to the bridge piers and as a restoring component to control an excessive girder response. Possible applications in bridge structures were discussed. A simple analytical model was established to characterize the dynamics of an example bridge featuring such a Bi-RIBS. A series of dynamic analyses were performed by using the proposed model to investigate the effects of several factors on controlling the seismic responses of the bridge, for example, the design parameters of Bi-RIBS including inclined angle and size, the damping property at the support interface, and the mass ratio. The peak ground accelerations of the bidirectional ground motion record were scaled to various levels to evaluate the maximum performance indices of the bridge structure and the response control effectiveness of the Bi-RIBS compared to the uncontrolled counterparts. The simulation results demonstrated that the proposed Bi-RIBS could effectively control the maximum pier displacement while keeping the bearing from overturning if suitable parameters were selected. In particular, the control effectiveness on the maximum pier response becomes more significant as the seismic intensity increases, due to its distinctive negative stiffness property. K E Y W O R D S3-D rocking motion, bidirectional rocking isolation bearing system (Bi-RIBS), bridges, maximum seismic response control, negative stiffness properties, orthogonally horizontal ground motions INTRODUCTIONThe introduction of a rocking mechanism into structures is recognized as a promising seismic response modification technique. The application of rocking structures in practical engineering dates back to the 1970s. 1,2 Various strategies are currently employed to address the rocking mechanism in modern structures, such as rocking walls, 3,4 rocking frame systems, 5-8 rocking podium structures, 9-11 and rocking bridge piers. 6,12 In particular, the latter three are related to theThis is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

Experimental study of a scaled bridge model with a unidirectional rocking isolation bearing system (Uni‐RIBS) through shaking table tests

“…Transverse restrainers are implemented to counter seismic actions induced by maximum considered earthquakes to mitigate falling girder risks in the transverse direction. Moreover, our prior research introduced the concept of bidirectional RIBS (Bi-RIBS) 35 through the 3-D extension of 2-D in-plane rocking motion, facilitating a bidirectional isolation effect on bridges by employing the 3-D wobbling motion of bearings. In terms of the principle of operation, upon exceeding the seismic action thresholds defined by the bearing's geometrical properties, Uni-RIBS activates its rocking mechanism, providing seismic isolation in the longitudinal direction.…”

Machine Learning Algorithms for the Prediction of the Seismic Response of Rigid Rocking Blocks

“…In contrast to fixed-base structural systems, whose seismic response is primarily governed by the dissipative energy process occurring at predefined locations through damage, free-standing structures' rocking response results in diminished structural damage, owing to the presence of negative post-uplift stiffness [2]. Apart from large-scale structures [3][4][5][6][7][8][9][10][11][12][13], non-structural elements within buildings may also uplift and rock [14][15][16] in response to floor accelerations [17,18].…”