斜靠式拱桥吊杆张力计算模型探讨

Research on calculating model of suspenders initial tension of double X-shape arch bridge

以斜靠式拱桥——平顶山市城东河路湛河桥主桥为工程实例,采用有限元程序MIDAS/Civil对该桥进行空间有限元离散,建立了斜靠式拱桥空间有限元计算模型.分别采用一次落架法、用吊杆张力设计值作为吊杆张拉控制力的计算方法及影响矩阵法3种不同方法,求解了吊杆初始张拉控制力.由3种不同计算模型得到的结果进行对比可以看出:采用影响矩阵法确定吊杆张力的计算模型得到的吊杆张力响应值与设计值吻合较好,保证了成桥时桥梁的内力和线形,是斜靠式拱桥确定吊杆张力的合适计算模型,对复杂空间异型梁拱组合桥的吊杆张力确定有较大的参考价值;其他两种方法计算结果的偏差均较大.

As an example, the main bridge of Zhanhe Bridge, a double X-shape arch bridge,over Chengdong River in Pingdingshan is discribed by the spatial FEM with MI- DAS/Civil program. With the FEM model,suspenders＇ initial tensions of the bridge are solved using three different methods of overall drop-frame method, using the design value of suspenders as its control tension method and influencing matrix method. By comparative analysis, it can be concluded that influencing matrix method, from which is suspender initial tension is derived, makes the suspender response tension fit very well with the design tension, and the bridge＇s internal force is ensured, this is suitable for certain suspender initial tension, which has great reference value for certain shaped archbeam combined structural suspender initial tension. By comparison, the other two method deviates are deviated from the experimental data.