Abstract: With the continuous increase of road vehicles and the service life of concrete cover beams, cracks have appeared in some bridge cover beams. Taking a bridge in Shijiazhuang as an example, by studying the possible impact on bridge cracking during the operation phase, the influence of vehicle load location, vehicle load size, and superstructure form on cracking of the large cantilever prestressed concrete cover beam under vehicle load is studied. The comparison is made with the bridge without vehicle load to determine the degree of impact of vehicle load on the cracking of the cover beam. The results show that the closer the vehicle load position is to the cantilever end, the greater the tensile stress of the cover beam, and the more severe the structural deflection. When the right lane experiences severe overloading, compared to the simultaneous overloading of the left and right lanes, the change in tensile stress is smaller, but the deflection of the cover beam is larger, about twice that of the overloading of the left and right lanes.

Key words: concrete cracking, large cantilever cover beam, overload

摘要： 随着路面车辆的不断增加以及混凝土盖梁使用年限的增加,部分桥梁的盖梁出现裂缝。以石家庄某桥梁为例,通过研究在运营阶段可能对桥梁开裂产生的影响,研究大悬臂预应力混凝土盖梁在车辆荷载作用下,车辆荷载位置、车辆荷载大小以及上部结构形式对盖梁产生裂缝的影响与桥梁在无车辆荷载时进行对比,确定车辆荷载对盖梁开裂的影响程度。结果表明:车辆荷载位置越靠近悬臂端,盖梁拉应力越大,结构的下挠越严重,右车道发生严重超载时与左、右车道同时超载相比,拉应力变化较小,但盖梁挠度较大,约为左、右车道超载时两倍。

关键词: 混凝土开裂, 大悬臂盖梁, 超载