柳州市维义大桥主桥设计与施工

Design and Construction of Main Bridge of Weiyi Bridge in Liuzhou City

柳州市维义大桥主桥采用(108+288+108)m中承式连续钢桁拱桥结构,为双向8车道城市桥梁,综述该桥的设计与施工情况。主桁由2片钢桁架组成,采用变高度N形桁式,2片桁中心距37 m,在2片主桁架的外侧各挑出3.25 m的悬臂托架支承人行道,桥面总宽度43.5 m。在主拱圈上、下弦杆平面及边跨桁架上弦杆均设置了菱形平联。桥面系采用正交异性钢桥面板结构,桥面铺装采用厚5.5 cm的环氧沥青混凝土。吊杆采用柔性钢绞线整体挤压拉索。主梁边、主跨均采用临时墩辅助的伸臂法架设,拱、梁同步安装,在跨中合龙。

The main bridge of the Weiyi Bridge in Liuzhou City is a half-through continuous steel truss arch bridge with span arrangement（108＋288＋108） m and is an urban bridge carrying dual four lanes.A summarized account of the design and construction of the bridge is presented herewith.The main trusses of the bridge are composed of two trusses employing the N-shape trusses with variable height and having a c/c distance of 37 m.At each outer side of the trusses,a 3.25 m wide part is cantilevered and bracketed,on which the sidewalk is placed and the deck of the bridge therefore has a total width of 43.5 m.At the plane of the upper and lower chords of the main arch rings and at the upper chords of the side span trusses,the diamond shape lateral bracings are arranged.The floor system of the bridge is the orthotropic steel deck structure that is surfaced with 5.5 cm thick epoxy asphalt concrete.The hangers are of the cables that are monolithically extruded from flexible steel strands.Both the main truss girders of the side and main spans are cantileveredly erected by the aid of temporary piers.The girders and truss arches are erected and installed in same step and are closed at the midspan.