Seismic control performance of a three‐story frame prototype equipped with semi‐active variable stiffness and damping structural joints

Abstract

This paper presents numerical and experimental studies on semi‐active seismic response control of structures equipped with variable stiffness and damping structural joints. Such adaptive joints, which are comprised of a shape memory polymer (SMP) core reinforced by an SMP‐aramid composite skin, function as load‐transfer components as well as semi‐active control devices. The SMP core material can transition from a glassy to a rubbery state through thermal actuation resulting in a shift of the structural natural frequencies and a parallel increase of damping ratio, which enables a new semi‐active control strategy. Control performance has been evaluated on a three‐story frame equipped with 12 adaptive joints and subjected to seismic excitations. Full‐transient analysis has shown that when the joints are thermally actuated to the transition temperature (65°C), acceleration and base shear are reduced by up to 62% and 65%, respectively. Shake‐table tests have been carried out on a 1/10‐scale prototype, confirming that through thermal actuation of the adaptive joints the structural damping ratio increases from 2.6% to 11.3% and the first natural frequency shifts by up to 37%. As the structure becomes more flexible, an increase of displacements and interstory drift might occur. However, depending on the seismic excitation, top‐story acceleration and base shear are significantly reduced in the range 43%–50% and 35%–51%, respectively. These results confirm that semi‐active control through thermal actuation of variable stiffness and damping structural joints is effective to mitigate the structure response under seismic excitation.

Research on seismic behavior of prefabricated building joints in China

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Reliability-based energy scheduling of active buildings subject to renewable energy and demand uncertainty

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“…Active structural control through sensing and actuation has been considered as a solution for meeting safety and serviceability criteria in the presence of severe loading events such as high winds and large crowds [5]. The authors demonstrated in [6] that semi-active building control may be employed to reduce the structure's reaction to seismic stimulation.…”

D1244: Design and Construction of the First Adaptive High-Rise Experimental Building

“…In (Senatore and Reksowardojo 2020) it has been shown that well designed adaptive structures can achieve up to 60% reduction of the whole-life energy (material + operational for actuation) compared to optimized passive structures. Semi-active control through thermal actuation of variable stiffness and damping joints were investigated to significantly reduce the dynamic response of a 1:10-scale multi-story building under earthquake loading (Wang et al, 2021). Adaptive façades have been investigated at different universities over the last years (Loonen et al, 2013;Bedon et al, 2019a;Bedon et al, 2019b).…”