【摘要】 针对地震作用下大跨斜拉桥主桥与多联引桥间易发生连锁碰撞现象,以一座典型大跨斜拉桥为研究背景,采用SAP2000 Nonlinear有限元程序,建立考虑主桥与多联引桥伸缩缝处碰撞效应的桥梁结构三维非线性计算模型,采用非线性时程分析法,研究大跨斜拉桥主桥与多联引桥伸缩缝处连锁碰撞效应对桥梁抗震性能的影响,并分析初始间隙、引桥周期比对连锁碰撞效应的影响规律。研究结果表明:若仅在引桥-引桥相邻梁体间发生碰撞,碰撞效应对短周期联引桥影响不大,但对长周期联引桥有一定影响,即会增大长周期联引桥梁端位移、梁墩相对位移以及固定墩墩底地震响应;而若主桥与多联引桥间发生连锁碰撞,不仅会显著增大短周期联引桥梁端位移、梁墩相对位移以及桥墩地震响应,而且会进一步增大长周期联引桥梁端位移、梁墩相对位移以及桥墩地震响应,更易引起各联引桥桥墩破坏或梁体落梁;随着初始间隙的增大,连锁碰撞效应对引桥结构的影响减弱;随着短周期联引桥基本周期的减小,连锁碰撞效应对短周期联的影响也有所降低。更多还原

【Abstract】 Because the pounding usually occurs at expansion joints between main span and multiple approach spans,a typical long-span cable-stayed bridge is analyzed. The three dimensional nonlinear dynamics model considering the effects of pounding at expansion joints between main span and multiple approach spans is established by SAP2000 Nonlinear software. Using the nonlinear time history analysis method,the effects of pounding at expansion joints on seismic performance of the bridge under earthquakes are studied and the influence laws of initial clearances and the natural period ratios between approach spans are analyzed. The results indicate that if the pounding only emerges between approach spans,it has little influence on the short-period unit approach span. However,the pounding has more influence on the long-period unit approach span because the pounding effects can amplify the deck displacement,the relative displacement between the deck and transitional pier,and the seismic response of its fixed pier. But if the pounding between main span and multiple approach span takes place,both the seismic responses of the short-period unit approach spans and long-period unit approach spans will be amplified. Furthermore,the piers of approach spans may be seriously damaged the decks may collpase. The effects of the pounding decrease with the increase of initial clearances.The effects on the short-period unit approach span also weaken gradually when the natural period of the short-period unit approach span decreases.更多还原