北川新县城禹王桥设计与施工

Design and Construction of Yuwang Bridge in New Beichuan County

北川新县城禹王桥为(56.1+72.0+56.1)m三孔钢筋混凝土箱形连拱桥(为风雨廊桥),桥梁上部采用传统羌族风情的钢筋混凝土框架建筑,边孔1层,中孔2层;主拱圈采用三室箱形截面,拱上四柱排架式立柱与建筑立柱对应,腹板与立柱对应(相交处设横隔板);桥面板采用现浇梁板,分跨处设缝断开,两端与碉楼连接处也断开;桥梁下部采用混凝土实体墩台、承台、群桩。主拱圈采用支架分段不分层现浇;施工期间边孔拱圈与桥台连接处设临时铰;桥墩采用施工期间推力墩形式,可单孔施工,单孔落架。

The Yuwang Bridge in New Beichuan County, a covered bridge, is a （56.1＋72＋ 56.1） m three-span reinforced concrete continuous box arch bridge. The superstructure of the Bridge is designed as reinforced concrete framework which has traditional Qiang Minority feature, the side span is of one storey, and the middle span of two stories. The arch ribs are three-cell box structure, the column of four-column bent frame on the arch ribs are placed in line with the posts of the framework, and the webs in Line with the columns （at the joint parts, diaphragms are add- ed ）. The bridge deck is cast in situ and cut where two neighbor spans are ：separated, and the bridge deck is also cut where the two ends of the bridge and the watchtowers are connected. The substructure of the bridge includes solid concrete piers, pier caps and group piles. The arch ribs are cast in segments but with no layers by scaffoldings. During the construction, provisional hin- ges are installed at the connections of side-span arch ribs and abutments. The piers take the form of the thrust pier in construction, which can be erected and lowered within a single hole.