阻尼模型对复杂结构水管桥地震响应分析的影响

Effects of Damping Model on Seismic Responses of Complicated Water Pipe Bridge

与对普通桥梁的抗震性能研究不同,对水管桥研究时需考虑动水压力的影响,以附加质量的形式模拟动水压力对水管桥动力特性和地震响应的影响.阻尼是结构动力响应分析中的重要参数,针对阻尼模型的合理选择进行讨论.水管桥自振特性复杂,对横桥向分别采用Rayleigh阻尼模型、分块Rayleigh阻尼模型进行动力计算;对顺桥向采用Rayleigh阻尼模型进行动力计算.两个方向均以振型叠加法所得结果作为精确解,评价了各阻尼模型的合理性.结果表明:分块Rayleigh阻尼模型更能合理地模拟结构横桥向振动的阻尼特性,而顺桥向按Rayleigh阻尼计算就能得到较好的精度.

Different from the seismic research on ordinary bridges, the influence of hydrodynamic pressure on the water pipe bridge should be considered when research on water pipe bridges; in the form of added mass simulating that the hydrodynamic pressure effects on the dynamic characteristics and seismic responses of the water pipe bridge. Damping is an important parameter in the structural dynamic analysis. The appropriate model of the damping is discussed. The complicated structural form of the water pipe bridge causes that its mode shape and form are complex. The paper analyzes seismic responses of the water pipe bridge in the longi- tudinal direction and the transverse direction of the bridge separately by using different damping models. In the transverse direction the paper uses the Rayleigh model and the damping matrix model assembled by Ray- leigh damping matrices in the structural dynamic analysis, while using the Rayleigh model in the longitudinal direction. From analytical results, it is found that the damping matrix model is directly assembled by Rayleigh damping matrices for different substructures components which can reasonably simulate the damping charac- teristics when the bridge vibrates in the transverse direction, while it can get the accurate results by the Ray- leigh damping model when the bridge vibrates in the longitudinal direction.