跨越通航内河桥梁净空尺寸选取探析

Discussion on Selection of Clearance Size of Bridge Crossing Navigable Inland River

广西某高速公路路线跨越通航内河洛青江。洛清江河道规划为Ⅲ级航道、通航500 t级船队、兼顾通航1000 t级单船。设计采用变截面连续箱梁一孔跨越航道。根据国家及当地对通航船只、船队尺寸的规定,桥梁与河流交角,流速,按照GB 50139—2014《内河通航标准》计算出双向通航孔最小净宽为123.9 m。根据最高通航水位,按照GB 50139—2014《内河通航标准》计算出通航最小净高为10 m,桥梁梁底最低高程为143.95 m。根据计算结果,桥跨选择为70 m+130 m+70 m,采用130m主跨一孔过河,梁底设计高程大于143.95 m。

A highway in Guangxi crosses the Luoqing river.Luoqing river is planned to be a class III channel,with a fleet of 500 tons and a single ship of 1000 tons.In the design,a continuous box girder with variable cross-section is used to cross the channel.According to the national and local regulations on the size of navigable vessels and fleets,the intersection angle between bridge and river,and the flow velocity,the minimum clear width of two-way navigable hole is calculated as 123.9 m according to the GB 50139—2014 Navigation Standard for Inland Rivers.According to the highest navigable water level and according to the GB 50139—2014 Navigation Standard for Inland Rivers,the minimum navigable clear height is 10 m,and the minimum elevation of bridge beam bottom is 143.95 m.According to the calculation results,the bridge span is 70 m+130 m+70 m,the main span of 130m is used to cross the river,and the design elevation of beam bottom is more than 143.95 m.