Rocking bridge piers equipped with shape memory alloy (SMA) washer springs

2020 ◽  
Vol 214 ◽  
pp. 110651 ◽  
Author(s):  
Cheng Fang ◽  
Dong Liang ◽  
Yue Zheng ◽  
Michael C.H. Yam ◽  
Ruiqin Sun
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Bridge Piers

Seismic Performance of Concrete Bridge Piers Reinforced with Hybrid Shape Memory Alloy (SMA) and Steel Bars

2019 ◽  
Vol 14 (01) ◽  
pp. 2050001
Author(s):  
Jize Mao ◽  
Daoguang Jia ◽  
Zailin Yang ◽  
Nailiang Xiang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Seismic Performance ◽  
Residual Deformation ◽  
Steel Reinforcement ◽  
Bridge Piers ◽  
Dissipated Energy ◽  
Concrete Bridge ◽  
Loss Of Function ◽  
Hybrid Reinforcement

Lack of corrosion resistance and post-earthquake resilience will inevitably result in a considerable loss of function for concrete bridge piers with conventional steel reinforcement. As an alternative to steel reinforcement, shape memory alloy (SMA)-based reinforcing bars are emerging for improving the seismic performance of concrete bridge piers. This paper presents an assessment of concrete bridge piers with different reinforcement alternatives, namely steel reinforcement, steel-SMA hybrid reinforcement and SMA reinforcement. The bridge piers with different reinforcements are designed having a same lateral resistance, or in other words, the flexural capacities of plastic hinges are designed equal. Based on this, numerical studies are conducted to investigate the relative performance of different bridge piers under seismic loadings. Seismic responses in terms of the maximum drift, residual drift as well as dissipated energy are obtained and compared. The results show that all the three cases with different reinforcements exhibit similar maximum drifts for different earthquake magnitudes. The SMA-reinforced bridge pier has the smallest post-earthquake residual displacement and dissipated energy, whereas the steel-reinforced pier shows the opposite responses. The steel-SMA hybrid reinforcement can achieve a reasonable balance between the residual deformation and energy dissipation.

Rocking isolation of bridge pier using shape memory alloy

2021 ◽  
Vol 16 (2-3) ◽  
pp. 85-103
Author(s):  
Rajesh R. Rele ◽  
Ranjan Balmukund ◽  
Stergios A. Mitoulis ◽  
Subhamoy Bhattacharya
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Lateral Displacement ◽  
Plastic Hinge ◽  
Time History ◽  
Bridge Pier ◽  
Bridge Piers ◽  
Isolation Technique ◽  
Residual Drift ◽  
Dynamic Time

The conventional design philosophy of bridges allows damage in the pier through yielding. A fuse-like action is achieved if the bridge piers are designed to develop substantial inelastic deformations when subjected to earthquake excitations. Such a design can avoid collapse of the bridge but not damage. The damage is the plastic hinge formation formed at location of maximum moments and stresses that can lead to permanent lateral displacement which can impair traffic flow and cause time consuming repairs. Rocking can act as a form of isolation by means of foundation uplifting which act as a mechanical fuse, limiting the forces transferred to the base of the structure. In this context, this paper proposes a novel resilient controlled rocking bridge pier foundation, which uses elastomeric pads incorporated beneath the footing of the bridge piers and external restrainer in the form of shape memory alloy bar (SMA). The rocking mechanism is achieved by restricting the horizontal movement of footing by providing stoppers at all sides of footing. The pads are designed to remain elastic without allowing their shearing. The pier, the footing and the elastomeric pads are assumed to be supported on firm rigid concrete sub base resting on hard rock. By performing nonlinear dynamic time history analysis in the traffic direction of the bridge, the proposed pier with the novel resilient foundation is compared against a fixed-based pier and classical rocking pier (CC). The proposed pier rocking on elastomeric pads and external restrainer (CP+SMA) has good re-centering capability during earthquakes with negligible residual drift and footing uplift. In this new rocking isolation technique, the forces in the piers are also reduced and thus leading to reduced construction cost with enhanced post-earthquake serviceability.

Seismic Vulnerability Assessment of a Multi-Span Continuous Highway Bridge Fitted with Shape Memory Alloy Bars and Laminated Rubber Bearings

2012 ◽  
Vol 28 (4) ◽  
pp. 1379-1404 ◽  
Author(s):  
M. A. Rahman Bhuiyan ◽  
M. Shahria Alam
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Vulnerability Assessment ◽  
Seismic Vulnerability ◽  
Longitudinal Direction ◽  
Bridge Piers ◽  
Highway Bridge ◽  
Seismic Vulnerability Assessment ◽  
Rubber Bearings ◽  
Bridge System

This study performs seismic vulnerability assessment in the longitudinal direction of a three-span continuous highway bridge, restrained by shape memory alloy (SMA) bars and isolated with laminated rubber bearings. The analytical simulation method based on incremental dynamic analyses is used in evaluating the seismic fragility functions of the bridge components (pier and isolation bearing) and the system. A two-dimensional finite element model scheme with nonlinear force-displacement relationships is used for the bridge piers and bearings. This study shows that the bridge piers with SMA bars have led to relatively higher seismic vulnerability over the bridge piers without SMA bars, which is also reflected in the bridge system. The isolation bearings with SMA bars have revealed comparatively less seismic vulnerability than those without SMA bars. From the numerical results, it is recognized that the failure probability of the bridge system is dictated by the bridge pier over the isolation bearing.

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