大跨度钢桁梁悬索桥临时连接方式分析研究

在大跨度钢桁梁悬索桥建造中，不同的钢桁梁段间的连接方式会直接影响桁架结构的实时与成桥的内力分布状态，所以临时连接方式的选择非常重要。以杨泗港长江公路大桥作为研究背景工程，分析逐步铰接法、逐步刚接法、适时铰接法3种连接方式进行对比，比选参数分别主要为钢桁梁构件和临时连接的受力情况、吊索索力等，获得结论为逐步刚接法因不能保证结构安全而不可行，逐步铰接法和适时铰接法安全可以保障，虽然适时铰接法需较多仿真计算和现场监测数据共同分析来确定钢桁梁铰接时机增加了工作难度，但在下弦杆的临时连接的措施下，比逐步铰接法的整体结构刚度和稳定性要好。此外，考虑在架梁过程中适当增加配重有利于主缆和主梁提前接近于成桥线形状态，并且可降低临时连接的受力大小的情况下，故以适时铰接法为研究基础，比较适时铰接法+无配重、适时铰接法+等额配重、适时铰接法+部分配重3种连接方式来分析配重的影响，得知采用适时铰接法+部分配重的连接方式的钢桁梁构件和吊索各项指标均为适宜，不仅较适时铰接法+无配重提前将下弦杆进行闭合可铰接状态，增加了主梁结构的刚度和稳定性，又较适时铰接法+等额配重中吊索索力安全系数满足要求，是最优的临时连接方式。

Analysis on temporary connection mode of the large-span steel#br#truss girder suspension bridge

During the construction of large-span steel truss girder suspension bridge, the temporary connection between steel truss girder segments has great influences on its construction. Different connection ways may directly affect the real-time and the bridge-completion internal force distributions of truss structure. With the Yangsigang Yangtze river highway bridge project taken as an example, three connection ways, including the gradually hinged method, gradually rigid connecting method and timely hinged method, were compared and analyzed. The parameters or variables for comparison were the forces, cable force, etc-in steel truss girder member and temporary connection. The research conclusions indicate that, the gradually rigid-connecting method is infeasible because it can’t ensure the structural safety, while the gradually hinged method and the timely hinged method can guarantee the structural safety. For the timely hinged method, the work difficulty may be increased as the simulation calculations and the field monitoring analysis are often combined for determining the hinging moment of steel truss girder, and the whole rigidity and stability of structure with the temporary connection measures of the lower chord are better compared to the gradually hinged method. In addition, counterweight was increased appropriately in the girder erection process for making the main cable and girder close to the curve shape of bridge-completion and reducing the forces of the temporary connection. Based on the research of timely hinged method, the timely hinged method without counterweight, the timely hinged method with equal counterweight and the timely hinged method with partial counterweight were compared for analyzing the effects of counterweight on steel truss girder. The research conclusions show that when the timely hinged method with partial counterweight is used, the indicators of truss girder and suspension cable are appropriate. Compared to the timely hinged method without counterweight, the timely hinged method with partial counterweight can close the lower chord into the hinged state in advance, enhancing the stiffness and stability of main girder structure. Compared to the timely hinged method with equal counterweight, the cable force of the timely hinged method with partial counterweight meet the requirements on safety factor, implying that it is an optimal way of temporary connection.