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  严琨,王立新,姜慧.伸缩缝刚度对大跨度悬索桥动力特性的影响[J].震灾防御技术,2017,12(3):667-676, DOI:10.11899/zzfy20170322.

伸缩缝刚度对大跨度悬索桥动力特性的影响
摘要:    伸缩缝作为大跨度桥梁与引桥之间的重要连接构件,其抗推刚度及可能存在的变异性对主桥及引桥动力特性的影响不可忽略。本文建立了大跨度悬索桥及引桥的有限元模型,采用弹簧单元模拟加劲梁与引桥箱梁之间的伸缩缝,分析伸缩缝刚度对悬索桥及引桥自振特性及其地震响应的影响规律。分析结果表明:伸缩缝刚度对加劲梁的横弯振型、竖弯与纵飘耦合振型的频率有明显的影响;伸缩缝刚度的变化会导致加劲梁与引桥的振型相互耦合,同时这些振型的频率发生相应的突变,当伸缩缝刚度较大时,加劲梁两个竖弯与纵飘的耦合振型解耦成为独立的竖弯和纵飘振型;当引桥与悬索桥加劲梁的纵飘振型发生耦合时,在纵向和竖向地震作用下的悬索桥及引桥的地震响应达到最小。伸缩缝刚度对悬索桥动力特性影响的分析可为悬索桥的模态参数确认、损伤识别、抗震性能分析提供有价值的借鉴。
作者单位
严琨 广东省地震局, 广州 510070;中国地震局地震监测与减灾技术重点实验室, 广州 510070;广东省地震预警与重大工程安全诊断重大实验室, 广州 510070 
王立新 广东省地震局, 广州 510070;中国地震局地震监测与减灾技术重点实验室, 广州 510070;广东省地震预警与重大工程安全诊断重大实验室, 广州 510070 
姜慧 广东省地震局, 广州 510070;中国地震局地震监测与减灾技术重点实验室, 广州 510070;广东省地震预警与重大工程安全诊断重大实验室, 广州 510070 
关  键  词:大跨度悬索桥  伸缩缝  抗推刚度  自振特性  地震响应
DOI:10.11899/zzfy20170322
基金项目:地震科技星火计划(XH16031),广东省地震预警与重大工程安全诊断重点实验室建设项目(2011A060901006),中国地震局地震监测与减灾技术重点实验室自主课题
收稿日期:2017-03-23
作者简介:严琨,男,生于1982年。博士,工程师。主要从事大跨桥梁结构分析理论、工程抗震、结构健康监测等方面的研究。E-mail:stefyk@163.com
通讯作者:
Dynamic Characteristics of Long-span Suspension Bridge with Variability of Stiffness of Expansion Joints
Abstract:      As an important connecting component between the long-span bridge and approach bridge, the anti-push rigidity and the possible variability of the expansion joints cannot be neglected for the dynamic characteristics of main bridge and approach bridge. The finite element model of long-span suspension bridge and approach bridge is established in this paper. The spring element is used to simulate the expansion joints between stiffening girder of suspension bridge and box girder of approach bridge, and the influence of stiffness of expansion joints on natural frequency characteristics and seismic response of suspension bridge and approach bridge is analyzed. The results show that:①The stiffness of expansion joints has a significant effect on the frequency of transverse bending modes and coupling mode frequency of vertical bending and longitudinal floating of stiffening girder. ②The change of stiffness of expansion joints may result in the coupling of stiffening girder and approach bridge, and the frequency of these modes may change accordingly. When the stiffness of the expansion joint is large, two coupling mode of vertical bending and longitudinal floating of stiffening girder are decoupled into two independent vertical and longitudinal vibration modes respectively. ③The seismic response of suspension bridge and approach bridge under the action of longitudinal and vertical earthquakes is minimized when the longitudinal floating mode is coupled between stiffening girder of suspension bridge and approach bridge. The analysis of influence of stiffness of the expansion joints on dynamic characteristics of suspension bridge can provide a valuable reference for the modal parameter identification, damage identification and seismic performance analysis of suspension bridge.
Keywords:  Long-span suspension bridge  Expansion joint  Anti-push rigidity  Natural vibration characteristic  Seismic response
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