低重心斜拉桥地震响应特性研究

Study results show that if it wants to control cable-stayed bridge's seismic force response, then it will pay large seismic displacement as cost and vice versa. The understanding is not comprehensive and accurate. So, it is necessary to study the influence of gravity center high on cable-stayed bridge seismic response characteristic and put forward the conception of low gravity center cable-stayed bridge. Build the first order longitudinal vibration frequents of floating cable-stayed bridge calculating model using double particles reverse pendulum type construction and the first order longitudinal vibration frequents of fixed-hinge bearing cable-stayed bridge calculating model using double particles type construction. Deriving first order vibration frequent calculating equation and then build the judgment criterion of low gravity center cable-stayed bridge. Research low gravity center cable-stayed bridge's seismic response characteristic and earthquake destroy mechanism. Utilizing the friction and self-locking principle, research a large tonnage safe-belt connection device for low gravity cable-stayed bridge, which is activated by earthquake acceleration. And then, build the safe-belt device mechanic model and derive its element's constitutive model. Form an innovation low gravity center cable-stayed bridge aseismic structure system, safe-belt connected structure system. On the basis, research the seismic response characteristic and seismic dissipation mechanism of low gravity center cable-stayed bridge and study the influence of gravity center high on cable-stayed bridge's strong earthquake damage mechanism and damage mode. At same time,do vibration platform model experiments study. The research not only has theoretical significance, but also has practical application value.

目前研究认为要使地震作用下斜拉桥的内力响应小，就要付出较大位移为代价，反之亦然，这种认识是不尽全面、不够准确的。为此，研究重心高度对不同结构体系斜拉桥地震响应特性的影响，提出低重心斜拉桥概念。建立飘浮体系斜拉桥纵向一阶振动频率双质点反向摆式简化模型和纵向固定铰接结构体系斜拉桥纵向一阶振动频率的双质点简化计算模型，推导纵向一阶振动频率计算公式，进而提出低重心斜拉桥判断准则，研究低重心斜拉桥地震响应特性和破坏机理。利用摩擦自锁原理研发以地震动加速度激活的大吨位安全带连接装置，建立其单元本构模型。提出一种新型低重心斜拉桥抗震结构体系- - 安全带连接体系，在此基础上，分析安全带连接体系低重心斜拉桥地震响应特性和减震机理；研究重心高度对不同结构体系斜拉桥地震破坏机理及损伤模式影响，并进行相应的振动台模型实验。该项目的研究不仅具有较强的理论意义，且具有较好的实际应用价值。

目前认为漂浮体系斜拉桥自振周期长，在地震作用下，主塔的内力响应比相同条件下铰接体系斜拉桥小，但纵向位移响应要比铰接体系斜拉桥大。要使地震作用下斜拉桥的内力响应小，就要付出较大位移为代价，反之亦然，这种认识是不尽全面、不够准确的。.为此，本项目在研究重心高度对不同结构体系斜拉桥地震响应特性影响的基础上，提出了低重心斜拉桥概念。从地震作用下斜拉桥惯性力传递路径入手，提出飘浮体系、固定铰接体系斜拉桥的双质点简化计算分析模型，利用刚度法和Rayleigh能量法分别推导了两种体系纵向一阶频率简化计算公式。根据不同体系斜拉桥纵向一阶振动频率计算公式，建立了低重心斜拉桥判断准则。并结合已建10座斜拉桥实例，验证了本文提出的斜拉桥纵向一阶自振周期简化计算公式和低重心斜拉桥的评价准则具有良好的稳定性，可用于斜拉桥的初步设计和方案比选，其误差在可接受的范围。利用摩擦自锁原理研发以地震动加速度激活的大吨位安全带连接装置和锁死销装置，建立了安全带和锁死销的单元本构模型。提出一种新型低重心斜拉桥抗震结构体系——安全带连接体系。以某斜拉桥为依托工程设计了4个1:25的斜拉桥振动台实验模型，分别进行了漂浮体系斜拉桥振动台实验、固定铰接体系斜拉桥振动台实验、安全带连接体系斜拉桥振动台实验和低重心斜拉桥纵向“人字形”塔振动台实验。通过模型实验和数值模拟研究了低重心斜拉桥的破坏特征和破坏机理。探讨了安全带连接体系低重心斜拉桥地震响应特性和减震机理，提出了斜拉桥安全带连接体系设计注意事项。本项目的研究不仅具有较强的理论意义，且具有较好的实际应用价值。该项目已经发表SCI论文3篇，EI论文15篇，EI期刊录用待发表论文2篇，EI/ISTP会议论文3篇，核心期刊论文8篇，获批发明专利6项。