大跨斜拉桥非一致激励地震响应研究

以海南某拟建斜拉桥为例,计算了该桥的动力特性,分析了该结构在一致输入地震激励和非一致输入地震激励下的非线性地震响应。计算结果表明:与一致输入地震激励下的结构响应相比,在非一致输入地震激励下桥梁结构最大响应值均有不同程度的增大。考虑纵向行波效应时,结构的纵向位移以及关键部位的内力响应值增大,这些响应值将随着地震波波速的提高而减小,并逐步接近一致输入地震激励下的响应值。

Investigation for Seismic Response of A Long-span Cable-stayed Bridge under Non-uniform Excitation

In this paper,the dynamic characteristics and the nonlinear seismic responses for the proposed cable-stayed bridge in Hainan Provinec under the uniform earthquake excitation and the non-uniform earthquake excitation are analyzed and computed.Through comparison of the computational results,it is found that the ratio of the torsion frequency and the bending-torsion frequency are high,so the torsion stiffness of this double-cable surface cable-stayed bridge is enough big.The maximum of the responses of the bridge structure under the non-uniform earthquake excitation are bigger than those under the uniform earthquake excitation.If the traveling effect of the longitudinal earthquake wave is considered in the response analyses,the longitudinal displacements and the internal forces in the important parts of the structure would increase.And these responses would decrease and be close to those under the uniform earthquake excitation with the increase of the wave velocity.