1建设背景在立交桥的建设中,为考虑其整体性和美观,匝道多为现浇连续箱梁,下部结构采用独柱独支座的也很多。经过10多年运行证明,这种结构形式总体上能满足运营要求,但随着交通流量的增大,重型和超载车辆日益增多,超速行驶时有发生。据统计,2003年全国范围公路货物车超载车辆占60%以上, 1 Construction Background In the construction of overpasses, in order to consider the integrity and aesthetics, the ramp is mostly a continuous cast-in-place box girder, and the lower structure adopts a single column and a single stand. After more than 10 years of operation, this type of structure can meet the operational requirements as a whole. However, with the increase of traffic volume, heavy-duty and overloaded vehicles are increasing day by day. According to statistics, in 2003, the nationwide overloaded vehicles on road freight vehicles accounted for more than 60%