【摘要】 研究目的：针对大轴重运输条件下既有铁路小跨度桥梁开裂严重、挠度偏大和振动加剧等系列问题，以某重载铁路30余孔12.0 m跨度板梁更换施工为背景，采用静载试验、数值模拟和实际工程应用等手段，开展新型小跨度整体式预应力板梁在大轴重运输条件下的静力适应性试验和极限承载能力研究，探索繁忙干线短时天窗条件下小跨度梁快速换架技术。研究结论：（1）1.2倍设计静活载作用下，小跨度整体式预应力板梁各关键截面的荷载-应变/位移曲线均呈线性变化，各控制截面应变及位移实测结果均小于理论计算值；试验过程中，板梁未发生开裂且始终处于弹性工作阶段；（2）整体式板梁发生破坏时的跨中弯矩为1.67×10~4 kN·m，破坏特征为顶部混凝土压溃；（3）采用“吊车+走行台车”的整体换架技术，能够在4 h短时天窗时间内实现整孔小跨度板梁的更换作业；（4）本研究成果可为重载铁路桥梁强化改造提供参考和借鉴。更多还原

【Abstract】 Research purposes: In response to a series of problems such as severe cracking, excessive deflection, and intensified vibration of existing railway short-span bridges under large axle load transportation conditions, taking the replacement construction of more than 30×12.0 m-span slab beams on a heavy-haul railway as the background, static load tests, numerical simulations and practical engineering applications were used to conduct static adaptability tests and ultimate bearing capacity research on a new type of short-span integral prestressed slab beam under large axle load transportation conditions, and to explore the rapid replacement technology of short-span beams on busy trunk lines.Research conclusions:( 1) Under the 1.2 times design static live load, the load strain/displacement curves at key positions of the short-span integral prestressed slab beam show linear changes, and the measured strain and displacement of each control section are smaller than the theoretical calculation values. During the experiment, the plate beam did not crack and remained in the elastic working stage.( 2) The results show that the mid-span moment of the integral plate girder is 1.67×10~4 kN·m when the damage occurs, and the damage is characterized by the collapse of the concrete at the top.( 3) By adopting the overall frame replacement technology of "crane+trolley", it is possible to replace the entire hole plate beam within four hours of skylight time.(4) The research results of this paper can provide a reference for the strengthening and renovation of heavy-haul railway bridges.更多还原