Li Yong, Yu Zijie, Wu Qifan, Liu Yongqian, Wang Shang
Laboratory of Roads and Railway Engineering Safety Control, Shijiazhuang Tiedao University, Shijiazhuang 050043, China.
Materials (Basel). 2022 Jun 1;15(11):3949. doi: 10.3390/ma15113949.
Precise evaluation for flexural ultimate capacity of bridges which are subjected to the collision of over-height trucks is essential for making decisions on corresponding maintenance, strengthening or replacement. When the span of a cross-line continuous bridge with a double-box girder was hit by an overly high vehicle, the concrete floor of one girder was severely damaged, and part of the prestressed strands and reinforcements in the girder were broken. After the double-box girder was removed and separated into two single box girders, the ultimate flexural capacity of both box girders was studied by destructive tests, and a comparison was made between the damaged and undamaged girders. Moreover, finite element analysis was conducted to simulate the failure process. The results show that the flexural bearing capacity of the damaged box girder decreased by 33%, but it was still 1.07 times greater than the design bearing capacity, which basically meets the design requirements. Also, the damaged box girder showed a desirable serviceable limit state for three-axle vehicles and five-axle vehicles, but showed an undesirable serviceable limit state for six-axle vehicles. This study shows that repairing or strengthening the damaged span may be better than demolishing and rebuilding the whole superstructure bridge.
精确评估遭受超高车辆碰撞的桥梁的抗弯极限承载力，对于做出相应的维护、加固或更换决策至关重要。当一座双箱梁跨线连续桥的跨中被超高车辆撞击时，其中一片梁的混凝土桥面板严重受损，梁内部分预应力钢绞线和钢筋断裂。将双箱梁拆除并分离为两片单箱梁后，通过破坏性试验研究了两片箱梁的极限抗弯承载力，并对受损梁和未受损梁进行了对比。此外，还进行了有限元分析以模拟破坏过程。结果表明，受损箱梁的抗弯承载力下降了33%，但仍比设计承载力大1.07倍，基本满足设计要求。同时，受损箱梁对于三轴车辆和五轴车辆呈现出理想的正常使用极限状态，但对于六轴车辆则呈现出不理想的正常使用极限状态。本研究表明，修复或加固受损跨段可能比拆除并重建整个桥梁上部结构更好。
