Construction Methods Of The. Caiyuanba Yangtze River Bridge Span Steel Box Arch

Caiyuanba Yangtze Bridge in Chongqing is the first basket handle steel box arch bridge for combined railway and highway traffic in China. The bridge carries six highway lanes on its upper deck as well as two tracks monorails on its lower deck. It is composed of prestressed rigid-frame structure, basket type steel box tie bar arch and steel trusses. The arch bridge is 800m long and has a 420m main span. The span of the enclosed steel box arch is 320m long. The height of the arch is 56.44m. The intilted angle of the arch is 10.67°. The bridge is located in the upper reaches of the Yangtze River. The seasonal influence on the construction is great. The drop of water lever is large too. The construction is difficult and time is limited. The construction of the basket handle arch is the key one in the construction of the Caiyuanba bridge. In this paper, the research work was done as follows:1. The typical construction methods of steel box arch were compared and analyzed. The various factors of construction, for example, the adaptable construction scheme, the construction equipment, the time limit, the influence on the navigation and so on, were considered. The construction scheme of cantilever splicing by cableway lift without supports was applied.2. The methods of the transportation and splicing were studied. According to the capacity of space for manufacturing, transportation and hoisting facilities, the arch was divided into 23 segments symmetrically. The method of transportation was shipping after two-segments assembling in factory. Then the segments one by one were lifted and spliced with cableway.3. The paper approached the erection one segments by other and determined that the symmetrical erection one by one with cableway was adopted. According to the order of the beginning, middle, closing of the arch, the construction of the arch was done. The beginning and middle ones were oriented accurately, then the arch of the bridge was finished once only.4. The choice and application of attachments was studied. The buckle were pulled to hang the segments after the erection of each segments had been finished. According to the need of construction temporary lateral braces were installed. Then connect the segments of upper and lower and increase the lateral stability in construction.