地震作用下桥梁梁体间的碰撞响应分析  

Analysis on the Pounding Responses between Adjacent Bridge Beams under Earthquakes

作　　者：陈学喜[1] 朱晞[1] 高学奎[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《中国铁道科学》2005年第6期75-79,共5页China Railway Science

基　　金：国家自然科学基金资助项目(50278002)

摘　　要：以一座3×16 m简支梁桥为例,进行3种地震波作用下桥梁的地震响应分析,研究梁体间的碰撞对桥梁结构地震响应的影响。研究结果表明,结构的碰撞响应与输入地震波的频谱特性、桥梁本身的动力特性及碰撞单元特性密切相关。在强烈地震作用下,桥梁碰撞力相当大,最大达到结构自重的21倍。碰撞易发生在桥台与主梁接触部位,且次数频繁,但峰值较小,发生时间多在地震波能量最大时刻。碰撞力随碰撞弹簧刚度的增加而增大,但增加幅度逐渐变缓,梁间设置压缩刚度较小的缓冲材料,可降低梁间的撞击力。采用柔性连接时,碰撞的瞬间作用对梁跨轴力影响明显,对最大支座反力、墩底弯矩、剪力的影响不明显,说明柔性支座在碰撞瞬间作用向桥墩传递过程中,有“隔减”的效果。The seismic responses of one 3 × 16 m simple-supported bridge under three kinds of seismic waves are analyzed to explore how beam poundings affect the seismic responses of the bridge structure. Results show that the pounding responses are tightly related with the frequency spectrum characteristics of the input seismic wave, the dynamic characteristics of the bridge and the characteristics of the pounding element. The pounding force between beams is relatively high during strong earthquake. The maximum pounding force reaches 21 times of the structure dead weight. Pounding actions normally occur at the contact position between the abutment and the main girder with high frequency and low peak value, and occur at the moment when seismic wave energy arrives at maximum. The pounding force increases with the increase of the pounding spring rigidity while the increasing speed is slowed down gradually. The pounding force between beams can be decrease if the buffer material with low compressive rigidity is installed between beams. When flexible connection is used, the instant pounding action influences the beam axial force evidently but has little effect on the bearing reaction force, moment at pier bottom and shear force at pier bottom. This shows that the flexible bearing has the function of vibration-diminishing and vibration-isolating.

关 键 词：桥梁 梁体碰撞 伸缩缝 地震响应 

分 类 号：U442.55[建筑科学—桥梁与隧道工程]