大跨悬索桥三维非平稳耦合抖振分析

基于Priestley(1967)演变功率谱模型，并采用Lin和Yang(1983)的建议，建立了脉动风速的非平稳功率谱模型。依据此模型，采用三维有限元法，建立了大跨桥梁非平稳耦合抖振运动方程。然后，将虚拟激励法和精细时程积分法相结合，建立了求解桥梁三维非平稳耦合抖振运动方程的快速算法。以某大跨悬索桥为例，分析了该桥的非平稳耦合抖振响应，并与平稳耦合抖振响应进行了比较。计算结果表明：随着脉动风速平稳部分持时的增大，非平稳抖振分析结果逐渐收敛于平稳抖振分析结果；但若脉动风速的平稳部分持时较短，非平稳抖振分析结果将低于平稳抖振分析结果。

3D non-stationary coupled buffeting analysis of long-span suspension bridges

Based on Priestley's evolutionary power spectral method (1967) and the suggestion by Lin and Yang (1983), a mathematical model of non-stationary power spectral of fluctuating wind velocities is proposed. Using this model, the 3D FEM-based dynamic equations of motion for non-stationary coupled buffeting analysis of long-span bridges are established, which is featured mainly by a combination of the pseudo excitation method and the precise integration method. With Tsing Ma suspension bridge in Hong Kong taken as a case study, the non-stationary buffeting analyses are compared with the stationary ones. It is shown that the non-stationary characteristics of the turbulen wind sometimes affects the structural responses significantly, particularly when the duration of the stationary part of the fluctuating wind excitations is not long enough compared with the basic period of the bridge. The results also show that the non-stationary coupled buffeting analysis method proposed in this paper is reasonable and efficient.