Experimental validation of semi‐active resetable actuators in a ⅕th scale test structure

Abstract

The seismic performance of a test structure fitted with semi‐active resetable devices is experimentally investigated. Shaking table tests are conducted on a ⅕th scale four‐storey building using 27 earthquake records at different intensity scalings. Different resetable device control laws result in unique hysteretic responses from the devices and thus the structure. This device adaptability enables manipulation or sculpting of the overall hysteresis response of the structure to address specific structural cases and types. The response metrics are presented as maximum 3rd floor acceleration and displacement, and the total base shear. The devices reduce all the response metrics compared with the uncontrolled case and a fail‐safe surrogate. Cumulative probability functions allow comparison between different control laws and additionally allow tradeoffs in design to be rapidly assessed. Ease of changing the control law in real‐time during an earthquake record further improves the adaptability of the system to obtain the optimum device response for the input motion and structural type. The findings are an important step to realizing full‐scale structural control with customized semi‐active hysteretic behaviour using these novel resetable device designs. Copyright © 2008 John Wiley & Sons, Ltd.

Earthquake Protection of Existing Structures with Limited Seismic Joint: Base Isolation with Supplemental Damping versus Rotational Inertia

“…Additionally, the class of socalled semi-active devices, having variable effective stiffness and/or variable effective damping, provides supplemental damping while keeping the overall base shear limited. In this context, resettable stiffness devices using electrorheological and magnetorheological materials have been increasingly developed [65][66][67] and studied in large-scale experimental validations in an attempt to optimize damping and minimize response by effectively reshaping and customizing the hysteretic loops (see, e.g., [68][69][70][71]). e nonlinearity of these models, including valve size, mass flow rate, and friction, has been investigated in experiments and numerical models [72].…”

Effectiveness of resettable energy dissipating devices in seismic response modification of elastic SDoF systems

“…Semi-active structural control has become popular because of its balance between passive and active control traits, exploiting the benefits of both without taking on their negative aspects [1][2][3][4][5][6][7]. The control algorithm requires a set of sensors/actuators to determine when to damp the structural response similar to active control, but does not add any additional energy to the system, being strictly dissipative [2,4,[8][9][10][11]. Furthermore, they do not require significant energy/power for their operation; thus, they provide significant resiliency during disruptive episodes.…”

“…This research aims at evaluating a relatively new class of semi-active variable stiffness energy dissipating systems with a decentralized control strategy. These systems offer significant capability in reducing displacement and/or base shear response of structures subject to lateral excitations similar to those induced by seismic and wind loads [4,5,11,20,[25][26][27][28]. The stiffness of such a system is manipulated in real time with insignificant levels of energy that makes them ideal for real world applications.…”

“…Despite their advantages, variable stiffness resettable devices are under-utilized mainly because of the shortage of fundamental research in quantifying the sensitivity of key seismic response parameters, and losses, in structures that use such systems for seismic hazard mitigation. These systems offer significant capability in reducing displacement and/or base shear response of structures subject to lateral excitations similar to those induced by seismic and wind loads [4,5,11,20,[25][26][27][28]. The performance (i.e.…”

“…These systems offer significant capability in reducing displacement and/or base shear response of structures subject to lateral excitations similar to those induced by seismic and wind loads [4,5,11,20,[25][26][27][28]. These systems offer significant capability in reducing displacement and/or base shear response of structures subject to lateral excitations similar to those induced by seismic and wind loads [4,5,11,20,[25][26][27][28].…”