单斜塔混合梁斜拉桥计算分析与试验

Analysis and Testing of Cable-stayed Bridge Structures with Single Oblique Tower and Steel-concrete Composite Beam

为了解桥跨结构的实际承载能力,研究其在使用荷载下的静、动力性能,针对—(112+48)m单斜塔双索面混合主梁斜拉桥进行结构受力分析,并进行成桥的静载与动载试验。采用专用程序建立全桥的有限元模型,分析设计荷载下的桥跨结构的荷载效应及其分布。根据桥跨结构的受力特性,针对主跨钢箱梁及边跨混凝土梁以及塔的最不利弯矩截面进行静载试验,测试对应梁体、塔的应力以及梁体、塔顶的位移,并进行斜拉索的索力测试。静载试验结果表明,桥跨结构实际受力状况与计算模式相符较好;静载下主跨钢箱梁,边跨混凝土梁及塔的实测应力相对较低;静载下几何位移基本小于计算值,说明实际桥跨结构具有良好的结构强度与刚度。同时采用脉动法进行自振特性测试,并进行行车、跳车激振试验,动力试验表明桥跨结构动力特性良好。

In order to know the actual bearing capacity and research the performance of the bridge structure under static and dynamic load, the structural analysis and static and dynamic loading test were performed on the steel-concrete composite beam and single oblique tower cable-stayed bridge with the spans of 112rn and 48m. The specific finite element analysis program was used to establish the calculation model and the load effects and its distribution under design load were analyzed. According to the characteristics of bridge structure, the static load tests were conducted on the most unfavorable moment section in main span of the steel box girder, the other concrete span and the tower. The stress and displacement of the girder and tower, and the tension of cables were measured during the loading test. The tests results show that the actual loaded state coincides well with the calculation model, the tested stresses of steel box girder and concrete girder and tower are relative lower than the calculation values; the tested displacements are smaller than calculation values. It is demonstrated that the bridge is of enough strength and stiffness. The free-vibration characteristics of the bridge were tested with microseism method, and the tests were done under passing vehicle with and without obstacle. The dynamic tests show fairly well dynamic performance of the bridge.