孟加拉新沙哈·阿曼纳特大桥设计与施工

Design and Construction of New Shah Amanat Bridge in Bengal

新沙哈·阿曼纳特大桥主桥为(115+3×200+115)m连续预应力箱梁矮塔斜拉桥。主梁采用带箱内斜撑的单箱单室薄壁箱梁;斜拉索采用单索面布置,在桥塔处从上塔柱转向鞍管穿过桥塔,两端锚固在主梁顶板与斜撑交汇处;桥塔由底座、下塔柱和上塔柱构成。上部结构箱梁0号块及1号块均在支架上现浇施工,墩顶临时固结形成T构,其它节段采用三角挂篮对称悬臂浇筑施工,合龙段采用合龙吊架施工,箱梁边跨现浇段采用支架现浇施工;桥塔采用定型钢模分次浇注施工;为便于箱梁现浇挂篮的安装,斜拉索施工滞后箱梁施工1个节段。该桥的结构特点最大限度地发挥了矮塔斜拉桥的工程经济性。

The main bridge of the New Shah Amanat Bridge is a continuous prestressed box girder extradosed bridge with span arrangement of （115＋3X200＋115） m. The main girder a- dopts the type of single cell box girder with thin walls and with diagonal struts installed inside the box. The stay cables, arranged in single cable plane, are threaded through the pylons via the de- viation saddle tubes installed in the upper pylon columns, the two ends of the stay cables are an- chored to the connection point of the top plate of the main girder and the diagonal strut. The py- lon is composed of pedestal, lower pylon column and upper pylon column. The sections No. 0 and No. 1 of the box girder of the superstructure were all cast in-situ on the scaffoldings and tem- porarily fixed to the pier top to form T frames. The remaining sections of the main girder were constructed by balanced cantilever cast, using the triangular form traveler, and the closure sec- tion was erected by lifting frames. The cast-in-situ sections of the box girder in the side spans were cast on scaffoldings. The pylon was cast step by step using set-shaped steel formwork. In order to facilitate the installation of the form traveler for box girder casting, the construction of the stay cables was carried out one section lagging behind the box girder construction. The struc- tural characteristics of the bridge enable the engineering economy of extradosed bridge to play to the utmost.