大跨度桥梁考虑桥塔风效应的随机风场模拟

SIMULATION OF STOCHASTIC WIND FIELD OF LONG-SPAN BRIDGES CONSIDERING WIND EFFECTS OF THE BRIDGE TOWERS

  • 摘要: 将谐波合成法与修正的谱描述法结合用于大跨度桥梁主梁及桥塔上的随机风场模拟。论述了利用谐波合成法对桥梁上顺风向风场的模拟过程,其中考虑了风谱沿高度的变化、由不对称互相关函数引起的重谱以及与频率有关的相位关系,对涉及的复数形式的目标谱密度阵给出了实用的分解方法。文中对用上述理论模拟出的风场样本进行了风谱的相关性检验,计算结果与目标值吻合良好,证明了所用模拟方法的可靠性。最后,使用该方法模拟生成了一座大跨度斜拉桥上随机风场的样本。

     

    Abstract: A combination of the wave superposition method and the modified spectral representation method is applied to a wind field simulation for whole bridge including the deck and the towers. In wave superposition method, the variation of the auto-spectrum with respect to the elevation and the quadrature spectrum caused by asymmetric cross-correlation function as well as the frequency dependent phase lag are all taken into account. A practical decomposition method is presented for the case which involves complex target cross-spectral density matrix. In a spectrum comparison, it is found that the correlation functions of the simulated wind field generated by the above methods agree well with the target correlation functions. This indicates that the method presented in this paper is reliable. Some of the stochastic wind field samples of a long-span cable-stayed bridge are given.

     

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