大跨双层钢桁斜拉桥地震响应分析及减震控制研究

Compared to single-deck long-span cable-stayed bridges, the most direct advantage of double-deck long-span cable-stayed bridge is the effective increase in permission of the traffic amount, the savage of land resources at the bridge site, and the good economical performance while the span of the bridge ranges moderately. Research on the seismic response of double-deck steel truss-girder long-span cable-stayed bridge and the seismic ruction will be performed in this research program. Firstly, procedures for random vibration analysis of cable-supported bridges subjected to spatially varying ground motions are presented based on the pseudo excitation method, with the consideration of initial equilibrium state, since the geometry nonlinearity. The seismic response of the bridge under uniform and multiple excitations are studied in detailed in time and frequency domain. Secondly, the effects of several energy dissipation devices, including nonlinear fluid viscous damper, elastic/inelastic connections, SMA dampers, etc on the seismic reduction of long-span double-deck steel truss-girder cable-stayed bridge are analyzed and the parameters optimization study are carried out. The dynamic behavior of the bridge willed studied when the energy dissipation devices fail suddenly. The reasons for the differences on the reduction of displacement and internal force of above energy dissipation devices are discussed with the consideration of dynamic character of structure and the related solutions are presented. Finally, an multi-protection composite dampers is presented based on the advantage and disadvantage of energy dissipation devices mentioned above and the analysis model and simplified formula will be presented, and the affectivity will be justified by experiment test.

相对于同等跨度的单层斜拉桥，双层斜拉桥最直接的优点是允许通行量有效增加、节约桥址处土地资源等，并且在适当的跨度内具有良好的经济性。本项目针对大跨双层钢桁斜拉桥地震响应及其减震控制开展研究。首先，针对大跨柔性结构几何非线性特点，在考虑初始平衡态影响情况下，给出了基于虚拟激励法的大跨桥梁多点激励随机响应计算流程；研究一致及多点激励下，大跨双层斜拉桥时域和频域内地震响应的特点。其次，系统研究多种被动减震措施（如非线性粘滞阻尼器、弹性/非弹性连接、SMA阻尼器等）的减震效果及其突然失效后的结构地震响应特点；对上述减震措施进行参数优化；从结构动力特性角度剖析不同减震措施对位移响应和内力响应减震效果不一的内在原因，并提出相应的解决措施。最后，根据既有被动减震措施的有效性与不足，构造多防线复合阻尼器，建立相应数值模拟模型、提出等效简化计算公式并进行试验研究以论证其有效性。

大跨双层斜拉桥在适当的跨度内具有良好的经济性，本项目针对大跨双层钢桁斜拉桥地震响应及其减震控制开展研究。针对大跨柔性结构几何非线性特点，在考虑初始平衡态影响情况下，基于Abaqus平台实现虚拟激励法的大跨桥梁多点激励随机响应计算。系统研究了多种被动减震措施（如非线性粘滞阻尼器、弹性/非弹性连接、SMA阻尼器、滑移剪切阻尼器等）对大跨双层斜拉桥的减震效果及结构地震响应特点；研究弹性连接失效及考虑支座仅受压特性下的桥梁时域地震响应特点。提出了一种针对非线性粘滞阻尼器的速度和位移简易放大措施。结合既有被动减震措施特点，构造多防线复合阻尼器，建立相应数值模拟模型并论证其有效性。