宽幅下承式空间多索面异型系杆拱桥设计关键技术

以外秦淮河大桥为工程背景，采用Midas Civil对该异型拱桥进行仿真模拟，首先探讨了不同主梁刚度、拱肋刚度两个参数条件下的拱桥结构受力性能影响规律；其次考虑异型拱桥结构最不利情况，进行了强度、刚度验算分析；另外计算了桥梁结构前五阶振型及自振频率，分析了其动力特性；最后针对拱肋可能会发生的失稳情况，进行了拱肋稳定性设计分析。结果表明：主梁与拱肋的变形、应力均满足设计要求；在10%~20%范围内改变主梁、拱肋结构刚度对结构受力影响较小，外秦淮河大桥作为城市交通景观桥梁，主梁与拱肋构造设计仍有一定的优化空间；桥梁前5阶的自振频率在0.49~1.25 Hz之间，动力性能较好，为抗震设计提供了参考；该异型拱桥结构具有较好的稳定性能。

Key Technology in Design of Wide Through Spatial Multi-plane Special-shaped Bowstring Arch Bridge

Taking the Outer Qinhuai River Bridge as the engineering background, Midas Civil is used to simulate the special-shaped arch bridge. Firstly, the effects of the stiffness of the main beam and the stiffness of the arch rib on the mechanical performance of the arch bridge are discussed. Secondly, by considering the most unfavorable situation of special-shaped arch bridge structure, the strength and stiffness are checked, calculated and analyzed. In addition, the first five vibration modes and natural vibration frequencies of the bridge structure are calculated, and the dynamic characteristics are analyzed. Finally, aiming at the instability of arch rib, the stability of arch rib is designed and analyzed. The results show that the deformation and stress of the main beam and arch rib all meet the design requirements. Changing the stiffness of the main beam and arch rib in the range of 10%~20% has little effect on the structural force. As an urban traffic landscape bridge, there is still some optimizing space in the structural design of the main beam and arch rib of the Outer Qinhuai River Bridge. The natural vibration frequency of the first five modes is 0.49 ~ 1.25 Hz, and the dynamic performance is good, which provides a reference for its seismic design. The structure of the special-shaped arch bridge has good stability performance.