大跨悬索桥加劲梁吊装阶段的施工控制

Construction Control of Long Span Suspension Bridges During Erecting Stiffening Girders

大跨悬索桥加劲梁吊装阶段的施工控制中,吊装前的控制计算和吊装期间的监测十分关键。为消除主缆施工期间产生的误差对加劲梁施工的影响,并保证成桥后桥面线形符合设计要求,提出了一种反馈控制分析方法;采用有限元正装计算方法计算各吊装阶段施工控制参数的理论值以及主索鞍自由滑移量等,并根据该滑移量和索塔的抗弯能力确定索鞍的顶推时机和顶推量。通过对宜昌长江公路大桥的施工控制,得出了主缆跨中标高、主索鞍的滑移以及钢箱梁的开口角等在加劲梁吊装过程中的变化规律,并保证了施工过程中结构受力的安全以及加劲梁吊装完后桥面线形符合设计要求。

It is important to carry out the construction control calculation before erecting stiffening girders and the monitoring during erecting the girders for controlling the long span suspension bridges.In order to eliminate the influence of the construction error taken place in the construction of the main cables on the construction of stiffening girders,and to ensure that the deck line shape agrees with the design line shape,a feedback control method is brougt forward.The theoretical values of the controlling parameters and the free slipping values of main saddles are calculated by the finite element method. On the basis of the slipping curves and the resistance to bending of the towers, the time and the value of pushing the saddles are determined. Through the construction control of Yichang Yangtze River Bridge, the variation regulari- ties of the height of the main cables, the slipping of the main saddles and the opening angle values of stiffening girders are obtained. At the same time, the safety of the structure during construction is guaranteed and the line shape of the deck conforms to the design specification after the erection finished.