桥梁工程本科毕业设计外文翻译---混凝土桥梁的结构形式-桥梁设计(编辑修改稿)

桥梁工程本科毕业设计外文翻译---混凝土桥梁的结构形式-桥梁设计(编辑修改稿)内容摘要：

pressways ,long spans facilitate access and minimize obstruction to activities below .Concern for environmental damage has led to the choice of long spans for continuous viaducts . For river crossings, intermediate piers may be impossible because of requirements of navigational clearance. In typical construction of this type, piers are castinplace, often using the slipforming technique .A ―hammerhead‖ section of box girder is often cast at the top of the pier, and construction proceeds in each direction by the balanced cantilever method. Finally, after the closing castinplace joint is made at midspan, the structure is further posttensioned for full continuity .Shear keys may be used on the vertical faces between segments, and precast are glued with epoxy resin. The imaginative engineering demonstrated by many special techniques has extended the range of concrete construction for bridges far beyond anything that could be conceived just a few years ago .In the United States, twin curved castin –place segmental box girders have recently been pleted for of span of 310 ft over the Eel River in northern California .Preliminary design has been pleted for twin continuous box girders consisting of central 550 ft spans flanked by 390 ft side spans. Another form of prestressed concrete bridge well suited to long spans is the cablestayed box girder .A notable example is the ChacoCorrientes Bridge in Argentina .The bridges main span of 804 ft is supported by two Aframe towers, with cable stays stretching from tower tops to points along the deck .The deck itself consists of two parallel box girders made of precast sections erected using the cantilever method .The tensio。