多点支撑加固坦拱桥试验研究

Research on Multi-point Supporting Strengthening Flat Arch Bridge

以多点支撑加固坦拱桥技术原理为依据，在完成2片模型试验拱的制作、加固前后测试的基础上，对比分析了圬工坦拱多点支撑加固增强处治前后主拱的应变、挠度、裂缝控制、破坏形态、极限承载力及支撑纵向钢筋应力指标。从加固前后试验拱的应变、挠度对比分析结果可看出：主拱经增设支撑加固增强处治后，强度、刚度明显提高，在同级荷载作用下，其应变值减少30％～40％，挠度值减少30％-50％，新增设的钢筋混凝土Y型支撑能与主拱协调变形、分担部分活载作用效应，提高了主拱的承载力。同时，增设的支撑对主拱裂缝的发展有抑制作用。该加固增强技术提高坦拱桥的承载能力的效果显著，可广泛应用于实践。

According to the principles of multi-point supporting strengthening flat arch bridge, based on the fabrication of two model arches and test of the model arches before and after strengthening, strain, deflection, crack control, failure mode, maximum beating capacity and stress of supporting longitudinal bar before and after flat arch multi-point supporting strengthening were compared and analysed. From the results of comparative analysis of the strain and the deflection, it can be concluded that （1） the strength and stiffness of the main arch supported by the additional reinforcement can be increased significantly, the strain and the deflection reduced by 30% to 40% and 30% to 50% respectively under the same loading condition; （2） the new Y-shaped RC component can harmonize deformation and share partial live-load effect with main arch to increase the bearing capacity of main arch; （3） the additional component can restrain the development of cracks in the main arch. The strengthening technology, which can be widely used in practice, can improve the bearing capacity of the flat arch bridge.