三塔单索部分斜拉桥模型试验研究

Model test on extra-dosed PC bridge with three towers and single stayed-cables

以福州市浦上大桥三塔单索部分斜拉桥主桥为原型,设计制作1∶40缩尺有机玻璃模型,开展三塔单索部分斜拉桥全桥有机玻璃模型试验和有限元结构分析,研究全桥弹性阶段结构受力性能.重点测试模型主梁变形、纵横向应力、桥墩和桥塔截面应力和支承反力,并模拟斜拉索换索状态,测试换索时结构受力性能变化情况.研究结果表明:三塔单索部分斜拉桥具有独特的受力特性,由于斜拉索的弹性支承能够承担部分活载作用,使主梁截面高度减小,结构轻巧优美、整体受力合理;但在换索时主梁应力明显增大,且变形增加约20%.

Extradosed PC bridge is a new type bridge, whose loading performance behaves between normal cable - stayed bridge and girder bridge. In order to deeply study its dimensional performance in elastic stage, an organic glass model test is taken based on Pushang main bridge. The model type, testing system, testing arrangement and loading methods are clearly designed. The displacement and stress of the main girder, the stress of the piers and towers and the support reaction is tested. According to the case of changing stayed cables, the situation of loading performance is tested too. A dimensional finite - element model is built to calculate, and the calculated result is similar to the tested result. The loading performance is validated in the test. Compared with continuous rigid girder bridge, the height of girder is smaller, due to the elastic support of stayed cables. Then the whole structure is light and loading in reason. But the power of stayed cable increases about 20% after one cable is changed.