Experimental investigation of life-time performance of unbounded natural rubber bearings as an isolation system in bridges

Maghsoudi-Barmi, Ali; Khaloo, Alireza

doi:10.1080/15732479.2020.1793208

Cited by 9 publications

(3 citation statements)

References 20 publications

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“…In their wok, 13 full-scale steel-reinforced elastomeric bearing specimens were constructed and tested to explore the effect of the long-term presence of vertical loads on the mechanical properties of the bearings. The results of their research indicated that although the long-term vertical loading can slightly change the vertical and shear stiffness and damping coefficient of bearings, their lifetime performance is satisfactory, and they can act as an isolation system [9]. In 2021, Xiang et al studied the effect of bearing installation method on the overall seismic behavior of bridges.…”

Section: Introductionmentioning

confidence: 99%

Application of Viscous Damper and Laminated Rubber Bearing Pads for Bridges in Seismic Regions

Dolati

Mehrabi

Dolati

2021

Metals

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Normally, Laminated Rubber Bearing Pads (LRBPs) are directly placed between girders and piers and their role is to provide the bridge span with horizontal movement, and to transmit the gravity loads from the deck to the piers. Although not designed for seismic loads, they can act as a fuse, partially isolating the substructure from the superstructure and keeping the piers intact during earthquakes. However, recent investigations show that large relative displacement of superstructure against substructure caused by sliding at bearing (sliding between girders and LRBPs) can cause expansion joint failure or even bridge span collapse. Accordingly, proper restrainers should be selected to prevent large displacement. Among all types of restrainers, viscous dampers as passive energy dissipation devices have shown a great capacity in damping earthquake energy. This study investigates the effectiveness of a VD-LRBP system, a viscous damper in conjunction with LRBPs, in dissipating energy and reducing the displacement of the superstructure with reference to the substructure caused by sliding at bearing during a seismic event. A Finite Element (FE) model was first developed and validated using available experimental and numerical results. With the validated model, a 3D Nonlinear Time History Analysis (NTHA) was conducted on a reinforced concrete bridge model under various records of earthquakes using OpenSees, an open-source finite element software. The relative displacement histories were recorded for the bridge in two cases: 1- with only LRBPs and 2- with viscous dampers and LRBPs (VD-LRBP system). The results of this study show that applying viscous dampers can reduce the relative displacement of the superstructure with reference to the substructure for up to 60 percent. As importantly, it can also reduce the residual displacement after the earthquake to near zero.

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Section: Introductionmentioning

confidence: 99%

Application of Viscous Damper and Laminated Rubber Bearing Pads for Bridges in Seismic Regions

Dolati

Mehrabi

Dolati

2021

Metals

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“…Natural rubber elastomeric bearings reinforced with steel shims, which are currently popular as bearings for service loads at bridges, are one of the firsts in line as low-cost isolators. Many have sought to investigate the inherent capabilities of steel-reinforced elastomeric bearings (SREBs) to provide improved structural performance under seismic excitations [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

“…Maghsoudi-Barmi et al [4] presented an experimental program to analyze the mechanical properties of steel-reinforced natural rubber bearings without the upper and lower endplates when subjected to large shear displacements, and to assess how they can be used and what the limitations are. In another study, Maghsoudi-Barmi and Khaloo [5] studied the lifetime performance of the ordinary elastomeric bearings as an isolation system. Other than the several experimental studies, numerical investigations were also carried out to develop a practical bilinear model capable of simulating the cyclic behavior of the SREBs while considering the interaction of axial and shear loads [7].…”

Section: Introductionmentioning

confidence: 99%

Seismic Risk Assessment of Optimally Designed Highway Bridge Isolated by Ordinary Unbounded Elastomeric Bearings

Maghsoudi-Barmi

Khansefid

Khaloo

et al. 2021

NMCE

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Recent experimental research has shown that ordinary unbounded steel reinforced elastomeric bearings (SREBs) can be considered as an attractive cost-effective option for the seismic isolation of highway bridges. To further investigate its benefits, the current study is focused on the seismic risk assessment of an optimally designed highway bridge isolated by SREB system. A typical three-span highway bridge located in Tehran Metropolis is considered and designed with the SREBs as isolation system, applying a multi-objective optimization procedure to reduce both the seismic isolation deformation and the base shear, simultaneously. Then, the vulnerability of the bridge is evaluated through an Incremental Dynamic Analysis (IDA) using a suite of 20 ground motion records, and the fragility functions are generated. Next, for the hazard modelling, all active faults around the site of the project are taken into account to simulate the earthquake scenario. Afterwards, probable earthquake scenarios during the design life of the bridge are generated randomly, including the events, as well as their corresponding synthetic stochastic accelerograms. In the last step, the response of the bridge and its losses are calculated under the entire scenarios. Finally, the seismic risk of the bridge is estimated. The results indicate an improved behavior of the bridge, and the capability of isolation system in mitigating the earthquake excitation. Moreover, the results, obtained from the assessed seismic risk, show a significant reduction in the amount of bridge losses.

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Probabilistic seismic performance assessment of optimally designed highway bridge isolated by ordinary unbonded elastomeric bearings

Maghsoudi-Barmi

Khansefid

Khaloo

et al. 2021

Engineering Structures

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Experimental investigation of life-time performance of unbounded natural rubber bearings as an isolation system in bridges

Cited by 9 publications

References 20 publications

Application of Viscous Damper and Laminated Rubber Bearing Pads for Bridges in Seismic Regions

Application of Viscous Damper and Laminated Rubber Bearing Pads for Bridges in Seismic Regions

Seismic Risk Assessment of Optimally Designed Highway Bridge Isolated by Ordinary Unbounded Elastomeric Bearings

Probabilistic seismic performance assessment of optimally designed highway bridge isolated by ordinary unbonded elastomeric bearings

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