Abstract In recent years, with the rapid development of China's transportation industry, some existing bridges have needed to be demolished and rebuilt. Bridge demolition is a complex process of structural system conversions. During demolition, the prestressed beam performance is not clear after anchorage system failure. Therefore, it is important to carry out research to better understand the behaviour of post-tensioned prestressed concrete members after anchorage failure. In this paper, the demolition project of the Qingkou interchange ramp bridge of the Fuzhou circumferential highway is taken as research background to carry out an experimental investigation on post-tensioned prestressed concrete beam specimens to study their mechanical performance before and after the failure of the anchorage system. The results show that the anchorage has a longitudinal extrusion effect on the concrete, and the contribution of the concrete and the rebar to the structure decreases from the end to the mid-span of the beams. The failure of the anchorage system affects the cracking load, the crack width and the ultimate bearing capacity, while it has no effect on the final crack distribution and the concrete failure mode. Beyond the limit of elasticity, the prestressing tendons and the concrete grout start to debond, and the bearing capacity of the beam decreases gradually. The crack resistance and the ductility of the prestressed concrete beams are also reduced. After concrete cracking and under the same load condition, the prestressing tendons bear a larger load in the case of anchorage system failure. It is suggested that after the failure of the anchorage system, the contribution of the residual stress in the prestressing tendons to the bearing capacity of the structure be taken into account until the limit of elasticity of the structure is reached.

中文翻译：

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锚固系统失效后简支后张梁试验研究

摘要 近年来，随着我国交通运输业的快速发展，部分既有桥梁需要拆除和重建。桥梁拆除是一个复杂的结构体系转换过程。拆除过程中，锚固系统失效后预应力梁性能不明确。因此，开展研究以更好地了解锚固破坏后后张预应力混凝土构件的行为非常重要。本文以福州环线高速公路青口立交匝道桥拆迁工程为研究背景，对后张预应力混凝土梁试件进行试验研究，研究其锚固破坏前后的力学性能。系统。结果表明，锚固对混凝土具有纵向挤压作用，混凝土和钢筋对结构的贡献从梁端到跨中逐渐减小。锚固系统的失效影响开裂荷载、裂缝宽度和极限承载力，而对最终裂缝分布和混凝土破坏模式没有影响。超出弹性极限，预应力筋和混凝土灌浆开始脱粘，梁的承载力逐渐下降。预应力混凝土梁的抗裂性和延性也降低。混凝土开裂后，在相同荷载条件下，预应力筋在锚固系统失效的情况下承受更大的荷载。