某四塔斜拉桥不同约束体系的动力特性研究

Research on the Dynamic Properties of One Four-tower Cable-Stayed Bridge Under Various Constraint Systems

依托于琼州海峡大桥的四塔斜拉桥设计方案,研究了在不同塔梁连接方式下结构的自振特性和地震作用下的弹性反应。根据地震分析结果,发现不同频谱特性的地震波对各约束体系影响不同,从而可能会得出不一致的结论。就一般意义而言,全漂浮体系动力性能优于半漂浮体系,而与约束体系相比,其主梁和边塔顶纵向位移都明显更大;全约束体系的抗震性能优于局部约束体系,且对主梁纵向位移约束最强,但与漂浮体系相比其桥塔内力和主梁竖向挠曲都更大。

Based upon the design plan of a four-tower cable-stayed bridge for Qiongzhou Strait Bridge, the paper investigates its modal properties as well as its elastic seismic responses under various pylon-girder constraint systems. In terms of the seismic analysis, different seismic waves with various frequency contents may influence bridge models differently, and then inconsistent conclusions can be drawn for the cable-stayed bridge under those constraint systems. In general, the dynamic performance of bridge with total floating system is better than bridge with semi-floating system, but compared with pylon-girder longitudinal constraint systems, it has larger girder and pylon longitudinal displacement; the system with all pylons constrained by girder has superior dynamic performance than partial constraint systems, also it has the highest constraint on girder displacement. But compared with floating system, the forces in pylons and the vertical displacement of girder are larger.