劲性骨架混凝土拱桥施工稳定性分析

Analysis of Stability of Steel-Frame Reinforced Concrete Arch Bridge at Construction Stage

天工大桥主桥为一座劲性骨架钢筋混凝土拱桥。为了研究该桥施工阶段的稳定性和风荷载、预应力对稳定系数的影响,通过建立以实体单元+梁单元为主的ANSYS三维有限元模型,模拟施工过程中钢管混凝土截面和混凝土箱形截面的分次浇筑过程。根据计算结果可知:该桥在施工过程中的稳定系数均大于4,满足规范要求;风荷载在拱肋截面分期浇筑成形阶段对稳定系数影响较大,因此,根据计算结果增设临时横撑;纵、横向预应力对稳定系数的影响均较小,分析时可考虑纵向系杆力,忽略横向预应力。

The main bridge of the Tiangong Bridge is a steel-frame reinforced concrete arch bridge.To study the stability,wind load and influence of prestressing on the stability factors of the bridge at construction stage,the three-dimensional finite element model of ANSYS mainly used with solid and beam elements was established and the concreting of the concrete-filled steel tube sections and concrete box sections of the bridge in times in the construction process was simulated.It is known from the results of calculation that the stability factors in the construction process are all greater than 4 which can meet the requirements in the relevant codes.The wind load at the stage of concreting of the arch rib sections in phases has considerable influence on the stability factors and the temporary lateral bracings are hence added in order to resist the wind load in accordance with the calculation.The longitudinal and transverse prestressing does not have much influence on the stability factors and in the analysis,the longitudinal tied member force can be considered while the transverse prestressing may be neglected.