Numerical simulations of a highway bridge structure employing passive negative stiffness device for seismic protection

Abstract

SUMMARYA new passive seismic response control device has been developed, fabricated, and tested by the authors and shown to be capable of producing negative stiffness via a purely mechanical mechanism, thus representing a new generation of seismic protection devices. Although the concept of negative stiffness may appear to be a reversal on the desired relationship between the force and displacement in structures (the desired relationship being that the product of restoring force and displacement is nonnegative), when implemented in parallel with a structure having positive stiffness, the combined system appears to have substantially reduced stiffness while remaining stable. Thus, there is an 'apparent weakening and softening' of the structure that results in reduced forces and increased displacements (where the weakening and softening is of a non-damaging nature in that it occurs in a seismic protection device rather than within the structural framing system). Any excessive displacement response can then be limited by incorporating a damping device in parallel with the negative stiffness device. The combination of negative stiffness and passive damping provides a large degree of control over the expected performance of the structure. In this paper, a numerical study is presented on the performance of a seismically isolated highway bridge model that is subjected to various strong earthquake ground motions. The Negative Stiffness Devices (NSDs) are described along with their hysteretic behavior as obtained from a series of cyclic tests wherein the tests were conducted using a modified design of the NSDs (modified for testing within the bridge model). Using the results from the cyclic tests, numerical simulations of the seismic response of the isolated bridge model were conducted for various configurations (with/without negative stiffness devices and/or viscous dampers). The results demonstrate that the addition of negative stiffness devices reduces the base shear substantially, while the deck displacement is limited to acceptable values. This assessment was conducted as part of a NEES (Network for Earthquake Engineering Simulation) project which included shaking table tests of a quarter-scale highway bridge model.

Simplified optimal design of MDOF structures with negative stiffness amplifying dampers based on effective damping

“…At first, applications of negative stiffness mainly concentrated on base‐isolated buildings and vibration control of cables . By engaging the NSD at a prescribed displacement, Nagarajaiah et al proposed the concept of apparent yielding, with which structures can achieve bilinear‐elastic behavior.…”

Experimental Study on Vibration Control of Suspended Piping System by Single-Sided Pounding Tuned Mass Damper

“…Compared to passive devices, active and semi-active controls are more effective at suppressing vibrations; however, the control devices require power sources, and components are normally more complex and more likely to fail [42]. In general, passive damping devices have the advantages of simple structure, easy maintenance, and high reliability, and have been widely implemented in mechanical, civil, and aerospace structures [43,44]. Commonly used passive vibration dampers include TMDs (tuned mass damper) [45,46], viscoelastic dampers, impact dampers [47,48], particle dampers [49,50], oil dampers, friction dampers [51,52], shape memory alloy (SMA) dampers [53][54][55], eddy current dampers [56][57][58], among others [59][60][61][62].…”

Experimental Shake Table Testing of an Adaptive Passive Negative Stiffness Device within a Highway Bridge Model

“…1.) and tested on a shake table at the University at Buffalo NEES Laboratory (UB-NEES) (Attary et al, 2012a(Attary et al, , 2012b(Attary et al, , 2013(Attary et al, , 2014. …”