在设计上海南浦大桥的过程中,因遇到东西两端引桥自接线处距地面不足3 m高的桥台与主桥桥面高达40m衔接,提升高差特大,设计引桥纵坡为4.5％。但若按常规采用支座,不仅纵坡不能大于2％,其引桥拉长,工程造价加大,而且由于该桥受地形所限,不能延长引 During the design of Nanpu Bridge in Shanghai, the abutment at both ends of the bridge had a bridging height of less than 3 m from the ground and up to 40 m in height. Due to the large elevation difference, the designed longitudinal gradient of the approach bridge was 4.5%. However, if the bearing is adopted conventionally, not only the longitudinal slope can not be larger than 2%, the extension of the approach bridge leads to an increase of the construction cost, and as the bridge is limited by the terrain, it can not be lengthened