Displacement-Based Seismic Design of Steel, FRP, and SMA Cable Restrainers for Isolated Simply Supported Bridges

Li, Shuai; Dezfuli, Farshad Hedayati; Wang, Jingquan; Alam, M. Shahria

doi:10.1061/(asce)be.1943-5592.0001231

Cited by 40 publications

(50 citation statements)

References 38 publications

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“…After designing the SMA‐reinforced piers, the effective stiffness, equivalent damping, and effective time period of the bridge can be determined. Then, the SMA restrainers can be designed according to the displacement‐based design procedure 40 . Considering the optimized configuration of the restrainer, 41 the allowable displacement, ∆ a , and the slack in restrainers, ∆ s , are set at 175 mm and 25 mm, respectively.…”

Section: Case Studymentioning

confidence: 99%

Seismic performance assessment of a multispan continuous isolated highway bridge with superelastic shape memory alloy reinforced piers and restraining devices

Wang

Alam

2020

Earthq Engng Struct Dyn

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The objective of this study is to analytically determine the effectiveness of a novel bridge system with superelastic (SE) shape memory alloy (SMA) reinforced concrete piers. The bridge is also equipped with SE SMA cable restrainers to prevent the bridge spans from a large displacement that can potentially cause span unseating. In the concrete bridge piers, the conventional steel reinforcements in the plastic hinge regions are replaced with SE SMA rebar to avoid large plastic deformation and improve its self-centering capacity. A typical three-span continuous highway bridge is modeled with SMA-reinforced piers and SMA restrainers. Numerical simulations of the bridge are conducted under destructive near-fault ground motions. The seismic responses and fragility curves of the novel bridge (Bridge IV) are assessed and compared with the reference bridge (Bridge I), the bridge with only SMA-reinforced piers (Bridge II), and the bridge with only SMA restrainers (Bridge III). The results revealed that the SMA-reinforced pier can successfully reduce the residual deformation and damage probability of the bridge; however, the bridge with only SMAreinforced piers is less efficient in preventing a large displacement. The use of SMA restrainers can efficiently limit the displacement of the bridge spans but increase the damage probability of the bridge piers. The proposed novel bridge having SMA-reinforced piers equipped with SMA restrainers (Bridge IV) is more efficient than the bridge with only SMA-reinforced piers (Bridge II)) or the bridge with only SMA restrainers (Bridge III).

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Section: Case Studymentioning

confidence: 99%

Seismic performance assessment of a multispan continuous isolated highway bridge with superelastic shape memory alloy reinforced piers and restraining devices

Wang

Alam

2020

Earthq Engng Struct Dyn

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“…It is evident from Equation (8) that the average impact force F in the pounding process is a function of the damping ratio ξ and stiffness k [21]. Therefore, when preventing bridge pounding, controlling the stiffness and damping of the structure will influence the pounding force.…”

Section: Of 24mentioning

confidence: 99%

“…The bridge has a single span of 30 m and a total span of 120 m, as shown in Figure 1a. Figure 1b shows the section of the girder, which consists of six small box girders with either reinforced or pre-stressed concrete, with a width of 17 m and a height of 1.6 m. The compressive strength of concrete used in the girder is 50 MPa, the elastic modulus is 34,500 MPa, and the bulk density is 25 kN/m 3 [21]. The piers of the bridge have a square cylindrical section, with a height of 15 m and a side length of 1.8 m, as shown in Figure 1c.…”

Section: Description Of the Bridgementioning

confidence: 99%

“…The researchers used experiments [7,8] and numerical simulation techniques to study different seismic measures, such as concrete shear keys [9][10][11], steel bar restrainers [12,13], cable restrainers [7,14], viscoelastic dampers, and innovative devices [15,16]. Numerical simulation techniques (including quasi-static [17][18][19], the seismic design method [20][21][22], and dynamic simulation [23][24][25][26]) are widely used for anti-seismic research on the prevention of pounding and unseating because of their advantages that they consume few resources and acquire a large amount of physical information.…”

Section: Introductionmentioning

confidence: 99%

“…They found that the inadequate performance of restrainers during large earthquakes remained elastic. Li et al [21] proposed a displacement-based seismic design method for cable restrainers in a three-span simply supported highway bridge; the behavior of cable restrainers was modeled using a tension-only elastic element with a gap/slack. The results show that the restrainers could remain functional and limit the relative displacement within a design value during earthquakes.…”

Section: Introductionmentioning

confidence: 99%

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Seismic Effectiveness of Multiple Seismic Measures on a Continuous Girder Bridge

Shi

Liu

2020

Applied Sciences

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Seismic hazards, such as bridge pounding, unseating, collapse, etc., cause significant economic losses and affect traffic and safety. Research on seismic measures, such as limiting and unseating prevention devices for the bridge, can effectively prevent damage to the bearings, such as excessive displacement, the pounding of the beam end, etc., in an earthquake. In this paper, the dynamic time-history analysis method was used to study the mechanical behaviors of the bridge structure, such as its seismic performance, structural displacement, pier bending moment, etc. We found that different combinations of seismic measures can effectively reduce the displacement at the bridge expansion joint and bearings. The joint application of an expansion device, restrainer, and unseating prevention devices shows the best limiting effect on bridge displacement and expansion joint displacement. The maximum reduction of bridge expansion joint displacement reaches 48% and is within the allowable deformation range of an expansion device in a large earthquake, and the maximum reduction of bearing displacement reaches 34%, which only slightly exceeds the shear deformation of the bearing. The expansion device, restrainer, and unseating prevention devices have smaller internal forces in this case than other cases, without damage. In contrast to the previous studies on single seismic measures of unseating restrainers, this study investigates the combination of multiple seismic measures and earthquakes of various magnitude. It reveals the catastrophe process of the bridge structure and the cooperation law of seismic measures in an earthquake.

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Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

Fang

Liang

Zheng

et al. 2021

Earthq Engng Struct Dyn

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This study presents a novel type of shape memory alloy (SMA) cable-restrained high damping rubber (SMA-HDR) bearing, which is particularly suited to nearfault (NF) regions where the pulsing effect potentially exists in the ground motions. The working mechanism of the bearing is first described, followed by an experimental investigation on a full-scale SMA-HDR bearing specimen. The test results confirm the efficient restraining effect offered by the SMA cables, which contribute to 65% and 24.4% of the lateral load resistance and total energy dissipation, respectively, prior to the initial fracture of the SMA cables. The failure of the cables is initiated near the end grip where moderate stress concentration exists at this region. Following the experimental study, the numerical modeling strategy for the bearing is discussed, and a case study is then presented, demonstrating the application of the SMA-HDR bearings in the Datianba #2 highway bridge, a real project that first adopts the proposed bearings in the world. A simplified design process is introduced for the bridge with novel SMA-HDR bearings to mitigate the potential damage during strong earthquakes especially the NF ones. The system-level analysis on the prototype bridge shows that the novel SMA-HDR bearings equipped with ten 7×7×1.2 SMA cables in each bearing could reduce the average maximum bearing displacement (MBD) by nearly 30% compared with the conventional bridge with HDR bearings. The application of the novel SMA-HDR bearing can significantly alleviate the pounding effect, especially under the NF earthquakes. The presence of the SMA cables tends to increase the maximum force response of the piers, but this effect is minor and under control.

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Displacement-Based Seismic Design of Steel, FRP, and SMA Cable Restrainers for Isolated Simply Supported Bridges

Cited by 40 publications

References 38 publications

Seismic performance assessment of a multispan continuous isolated highway bridge with superelastic shape memory alloy reinforced piers and restraining devices

Seismic performance assessment of a multispan continuous isolated highway bridge with superelastic shape memory alloy reinforced piers and restraining devices

Seismic Effectiveness of Multiple Seismic Measures on a Continuous Girder Bridge

Seismic performance of bridges with novel SMA cable‐restrained high damping rubber bearings against near‐fault ground motions

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