格构式钢塔斜拉桥动力测试及动力影响分析

Analysis on Dynamic Test and Dynamic Influence of Lattice Steel Pylon Cable-stayed Bridge

为研究格构式钢塔斜拉桥的动力特性,以宝鸡市陆港大桥为背景,采用脉动测试法对桥梁的动力特性现场测试,与有限元模型值进行对比分析;在此基础上,分析主塔刚度、主梁刚度、边跨辅助墩、主塔高度等参数变化对该桥动力特性的影响。结果表明:实测模态振型与理论振型基本一致,实测频率值略大于理论值;格构式钢塔斜拉桥塔梁振型容易被同时激发,互相耦合,互相牵动,不利于抗震;桥塔整体扭转刚度大,有利于提高结构的抗风能力;边跨辅助墩可以大幅提高桥梁纵向刚度和竖向刚度,能增强结构抗风性能,并提高行车舒适性;就其动力特性方面,此种桥型最佳索塔高跨比介于1/3~1/2.5之间。

In order to study the dynamic characteristics of lattice steel pylon cable-stayed bridge,taking Baoji Lugang Bridge as the background,the dynamic characteristics of the bridge are measured by pulsation test method,and compared and analyzed with the finite element model value.On this basis,the influences of the parametric change of the main pylon stiffness,main girder stiffness,side span auxiliary piers,main pylon height and other parameters are analyzed.The results show that the measured modal vibrating shape is basically consistent with the theoretical modal vibrating shape,and the measured frequency value is slightly larger than the theoretical value.The vibrating modes of the pylon and girder of lattice steel pylon cable-stayed bridge are easy to be excited at the same time,coupled with each other and affected each other,which are not conducive to earthquake resistance.The whole torsional stiffness of bridge pylon is big enough to improve the wind resistant capability of structure.The side span auxiliary piers can greatly improve the longitudinal rigidity and vertical rigidity of the bridge,which can enhance the wind resistance of the structure and improve the driving comfort.For its dynamic characteristics,the best pylon-to-span ratio of this type of bridge is between 1/3 and 1/2.5.