Seismic Isolation Performance of a Concrete Continuous Girder Bridge Based on High-Damped Rubber Bearings

Author(s):  
Chang-jiang Shao ◽  
Guo-qing Han ◽  
Lin Fang ◽  
Yong-jiu Qian
2011 ◽  
Vol 243-249 ◽  
pp. 1928-1934 ◽  
Author(s):  
Tian Bo Peng ◽  
Zhen Nan Wang ◽  
Xun Tao Yu ◽  
Cheng Yu Yang

The double spherical seismic isolation (DSSI for short) bearing has been adopted in seismic design of several important engineering projects since developed recently. It was used generally as fixed bearings in a continuous girder bridge in these projects, and only a few fixed piers, usually just one fixed pier would transmit the horizontal earthquake action to the foundation, which is uneconomical and results in the much larger seismic risk in the longitudinal direction of a continuous girder bridge than that in the transverse direction. In order to share the earthquake effect with all the piers and avoid relative vertical displacement among all the bearings under the normal traffic conditions, a new seismic design method of continuous girder bridges is introduced. The configuration and working mechanism of two kinds of DSSI bearings used to make the new seismic design possible are introduced. It’s shown that the method is preferable for the seismic design of continuous girder bridges by a numerical seismic analysis with a four-span continuous girder bridge.


2010 ◽  
Vol 29-32 ◽  
pp. 209-214
Author(s):  
Wen Jing Liu ◽  
Li Li ◽  
Kun Ye

LRB base isolation technology is different from the traditional continuous girder structure system, and shows good isolation performances. However, because fixed piers were canceled and all bearings were LRB, it is often considered that the reliability of structure might be reduced. Therefore, the reliability of LRB continuous girder bridges subject to seismic excitation was systematically studied from different indicators for the first time in this paper, the world's first double traffic double deck isolated continuous girder bridge – Dongjiang double-layer-pier isolated approach bridge in Dongguan of Guangdong province was adopted as study case. The results shows that, when the effect of pile-soil interaction is considered, LRB system still has a very good isolation performance; pounding subjected to seismic must be analyzed; dynamic stability needs checking when higher piers and larger earthquake displacement. Generally speaking, the reliability of LRB continuous girder bridges subject to seismic excitation won’t be reduced.


2013 ◽  
Vol 353-356 ◽  
pp. 2000-2003
Author(s):  
Peng Zhang ◽  
Cui Ping Pang ◽  
Min Yuan ◽  
Wan Wen Wang

The seismic performance of multi-span simply supported steel-girder bridges with sliding and high rocker steel bearings is poor during earthquakes. During the past 20 years, seismic isolation has emerged as one of the most promising strategy for improving the seismic performance of existing bridges. In this study elastomeric bearings, lead-rubber bearings, and cable restrainers are attempted to modify the seismic response of bridges, and theirs effects are analyzed and compared.


2021 ◽  
Vol 11 (10) ◽  
pp. 4431
Author(s):  
Gyeong-Hoi Koo ◽  
Tae-Myung Shin ◽  
Sang-Jin Ma

To assure seismic isolation performance against design and beyond design basis earthquakes in the nuclear facility components, the lead inserted small-sized laminated rubber bearings (LRB), which has a 10 kN vertical design load, have been designed and quasi-statically tested to validate their design mechanical properties in previous studies. Following this study, the seismic shaking tests of these full-scale LRBs are performed and discussed in this paper with the dummy mass system to investigate actual seismic isolation performance, dynamic characteristics of LRBs, consistency of the LRB’s quality, and so on. To study the seismic isolation performance, three beam structures (S1–S3) with different natural frequencies were installed both on the shaking table and the dummy mass supported by four LRBs: (1) S1: structure close to seismic isolation frequency; (2) S2: structure close to peak input spectral frequency; (3) S3: structure in the high-frequency region. The test results are described in various seismic levels of OBE (Operating Basis Earthquake), SSE (Safe Shutdown Earthquake), and BDBE (Beyond Design Basis Earthquake), and are compared with the analysis results to assure the seismic isolation performance and the LRB’s design parameters. From the results of the shaking table tests, it is confirmed that the lead inserted small-sized LRBs reveal an adequate seismic isolation performance and their dynamic characteristics as intended in the LRB design.


Author(s):  
Satoshi Fujita ◽  
Keisuke Minagawa ◽  
Mitsuru Miyazaki ◽  
Go Tanaka ◽  
Toshio Omi ◽  
...  

This paper describes three-dimensional isolation performance of seismic isolation system using air bearings. Long period seismic waves having predominant period of from a few seconds to a few ten seconds have recently been observed in various earthquakes. Also resonances of high-rise buildings and sloshing of petroleum tanks in consequence of long period seismic waves have been reported. Therefore the isolation systems having very long natural period or no natural period are required. In a previous paper [1], we proposed an isolation system having no natural period by using air bearings. Additionally we have already reported an introduction of the system, and have investigated horizontal motion during earthquake in the previous paper. It was confirmed by horizontal vibration experiment and simulation in the previous paper that the proposed system had good performance of isolation. However vertical motion should be investigated, because vertical motion varies horizontal frictional force. Therefore this paper describes investigation regarding vertical motion of the proposed system by experiment. At first, a vertical excitation test of the system is carried out so as to investigate vertical dynamic property. Then a three-dimensional vibration test using seismic waves is carried out so as to investigate performance of isolation against three-dimensional seismic waves.


Author(s):  
Qiwen Jin ◽  
Zheng Liu

In-service bridges, under long-term service operational environment, are usually accompanied by different damage types. Traditional method for the measure point arrangement of in-service bridge SHM is usually based on engineering experience. A large number of SHM sensors are usually arranged on the structure, followed by a high engineering cost and a heavy maintenance task. These sensors will also produce large amounts of data, creating a challenge for operators requiring to deal with data processing in an effective manner. This study serves as a part of the series of studies on the measure point arrangement strategy of in-service bridge SHM. In this study, the SHM sensor measure point arrangement of in-service continuous girder bridge (a common structural style of high way bridge in China) is proposed. Two-span continuous beam, three-span continuous beam, and four-span continuous beam are taken as examples. Detailed comparison and verification are also performed with consideration of numerical simulation and previous studies. Different traffic speeds and different bridge spans are considered. The effect of different damage locations and different damage degrees are analyzed in detail. This study shows that a general similar trend can be observed for the structural robustness of in-service continuous girder bridge. The elements with smaller structural robustness of this kind of bridge are basically located around the middle cross section of side spans (first span and last span), followed by the middle span. Moreover, the numerical value of structural robustness of different elements in a continuous girder bridge is significantly different from each other, due to the complexity of the joint effect of different traffic speeds and damage locations. Therefore, the measure point should be generally arranged at the side span firstly, followed by the middle span. With consideration of the specific traffic speed and damage location in engineering application, a detailed analysis is also proposed for the further optimization of SHM sensor measure point arrangement. Once the elements are arranged in order of the numerical value of structural robustness, the SHM sensor measure point arrangement of this kind of bridge can be more targeted, and the number of sensors can also be greatly reduced.


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