Large strain nonlinear model of lead rubber bearings for beyond design basis earthquakes

Eem, Seunghyun; Hahm, Doshik

doi:10.1016/j.net.2018.11.001

Cited by 31 publications

(20 citation statements)

References 13 publications

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“…For investigating the behavioral accuracy of the isolator in the software, the isolator used in the Eem et al's [23] paper was selected to compare the base isolation's performance in experimental work and Seismostruct software. The design of the seismic isolation system usually determines the LRB's primary stiffness (K 1 ), secondary stiffness (K 2 ), and characteristic strength (Q d ), as shown in Fig.…”

Section: Validation and Design Of Base-isolatormentioning

confidence: 99%

On Seismic Response Reduction of Adjacent Frame: Emphasis on the Different Characteristics of Earthquakes

2021

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Seismic response reduction of adjacent frames with the use of dampers, base isolations, or hybrid controls has been considered in recent years. What makes this to be highly important are the different properties of input earthquake loadings that can lead to different results. In this study, friction dampers and LRB isolators were used as the passive energy absorbers and, accordingly, the performance of such devices subjected to a wide range of earthquake loadings has been studied. Two experimental samples were considered to be used as model verifications. Afterward, the frames were excited by three sets of far-fault, near-fault, and near-fault with pulse records, and then the seismic responses of the frames were evaluated in the forms of displacement, inter-story drift, and acceleration. Subsequently, efficient techniques for implementing passive control devices were proposed. The results showed that the hybrid control strategy (a combination of devices) is the most efficient technique for all three statuses; however, using the base-isolation technique can also lead to acceptable performance. When the height of the frame increases, the role of the damper in the reduction of inter-story drift decreases. Nevertheless, the maximum displacement caused by near-fault with pulse records in the base isolation deceives is the main concern in using such devices. The rate of reduction of structural drift in near-fault with pulse records by using hybrid control was significant so that in 3-, 5-, and 8-story frames this reduction was 77%, 85%, and 87%, respectively.

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Section: Validation and Design Of Base-isolatormentioning

confidence: 99%

On Seismic Response Reduction of Adjacent Frame: Emphasis on the Different Characteristics of Earthquakes

2021

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“…Here, the allowable displacement of the restrainer is set at the shear deformation of the LRB at a collapse damage state (i.e., 250% shear strain of LRB). Since the modern isolation bearings can experience high shear strains (e.g., 400%) with no failure, the designed restrainers can effectively prevent LRBs from collapse 55,56 and as a result, the bridge can remain serviceable even after strong earthquakes. The required length of the restrainers is calculated as 2300 mm.…”

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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“…Therefore, more studies on the seismic performance of NPP structures are needed. Base isolators such as Lead Rubber Bearing (LRB) or friction pendulum systems can mitigate the possibility of damage to the civil structures and NPPs during an earthquake [1][2][3][4]. Numerous studies have been conducted on the effects of base isolators and the seismic performance of base-isolated NPP structures.…”

Section: Imentioning

confidence: 99%

Seismic Responses of NPP Structures Considering the Effects of Lead Rubber Bearing

Nguyen¹,

Nguyen²

2020

Eng. Technol. Appl. Sci. Res.

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Abstract-This study investigates the effects of Lead Rubber Bearings (LRBs) on Floor Response Spectra (FRS) of Nuclear Power Plant (NPP) structures. Three main structures in the Advanced Power Reactor 1400 (APR1400) NPP including the reactor containment building, an internal structure, and an auxiliary building were numerically developed in SAP2000. The structures were modeled using beam stick elements, and lumped masses were assigned to beam element nodes. All equivalent section properties of beam elements were calculated based on the designed cross-sections of the structures. A series of 40 ground motions with response spectra scaled to match the NRC 1.60 spectrum were utilized in numerical time-history analyses. Finally, a thorough comparison of FRS was conducted at different elevations of the structures, considering both with and without LRB. Numerical results showed that the FRS of base-isolated structures at higher elevations was significantly reduced compared to non-isolated structures. However, at lower elevations, the FRS was higher for the base-isolated structures compared to the non-isolated ones. Additionally, at a low-frequency range, roughly smaller than 3 Hz, the FRS of base-isolated structures was always greater than that of the non-isolated ones.

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Large strain nonlinear model of lead rubber bearings for beyond design basis earthquakes

Cited by 31 publications

References 13 publications

On Seismic Response Reduction of Adjacent Frame: Emphasis on the Different Characteristics of Earthquakes

On Seismic Response Reduction of Adjacent Frame: Emphasis on the Different Characteristics of Earthquakes

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

Seismic Responses of NPP Structures Considering the Effects of Lead Rubber Bearing

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