基于反应谱法的低重心斜拉桥判定简化计算

Simplified criterion for low gravity center cable-stayed bridge based on response spectrum

为便于斜拉桥抗震方案比选,建立全漂浮体系斜拉桥反向双质点简化分析模型和纵向铰接体系斜拉桥双质点简化分析模型,并推导2种体系斜拉桥纵向一阶自振周期的简化计算公式。根据反应谱计算理论得到全漂浮体系和纵向铰接体系斜拉桥塔底弯矩的简化计算公式,提出简化的低重心斜拉桥判定公式,并与10座已建斜拉桥的有限元计算结果进行对比验证,弯矩吻合良好。研究结果表明:2种不同体系斜拉桥纵向一阶自振周期简化计算公式均具有较高的计算精度,基于反应谱法提出的低重心斜拉桥简化判定公式具有较高的可靠性,可为斜拉桥初步设计时抗震方案必选提供参考。

In order to make scheme comparison of cable-stayed bridges convenient,the reverse double-mass model for full floating cable-stayed bridges and the double-mass model for fixed hinge cable-stayed bridges were developed,and based on the simplified models,the formulas were derived.Then,on the basis of the double-mass models and the response spectrum,the simplified calculation of the bottom bending moment and simplified criterion of low gravity center cable-stayed bridges were put forward.Finally,the proposed models and simplified calculation were evaluated by the tests on ten built-up bridges and the simplified calculation results were matched well with those analyzed by finite element method.The results show that the two simplified models have higher accuracy and the criterion of low gravity center cable-stayed bridge is reliable,they can be adopted in preliminary design and scheme comparison of cable-stayed bridges.