援马尔代夫中马友谊大桥主梁钢箱梁设计

Design of Steel Box Girder for Main Girder of China-Maldives Friendship Bridge Aided to Maldives by China

援马尔代夫中马友谊大桥主桥为(100+180+180+140+100+60)m混合梁连续刚构桥。该桥跨中部分梁段采用变高度钢箱梁,单箱双室倒梯形结构,横向两侧设置挑臂,桥面总宽21.0m。钢箱梁采用节段全焊接制造,节段间采用栓焊组合方式连接。钢箱梁材质为桥梁用结构钢,其外表面与大气接触的顶板、底板、边腹板和挑臂采用耐大气腐蚀钢;端部设密封门,实现气密防腐;内、外表面均采用长效防腐涂装,利用综合防腐措施以提高钢梁在海洋环境下的耐久性。采用UHPC+SMA13的复合铺装结构以提高铺装耐久性。钢箱梁采用工厂小节段制造、现场大节段拼装、纵向顶推就位的方法施工。

The main bridge of China-Maldives Friendship Bridge aided to Maldives by China is a continuous hybrid girder rigid-frame bridge with the spans of（100＋180＋180＋140＋100＋60）m.For the part of the girder segments at the midspan of the bridge,the steel box girder of variable depth is used.The steel box girder is an inverted trapezoidal structure of double cells and single box,on the both sides of the girder in the transverse direction,the cantilever arms are arranged and the total width of the deck is 21.0 m.The weathering steel is used for the top plates,bottom plates,side webs and cantilever arms of the steel girder since the outer surfaces of these plates,webs and arms are exposed to the atmosphere.At the ends of the girder,the sealing doors are set to realize the air tightness and corrosion prevention.The internal and outside surfaces were coated by the long-acting corrosion prevention coating.The comprehensive corrosion prevention measures are taken to improve the durability of the steel girders under the marine environment.The UHPC＋SMA13 composite pavement structure is adopted to improve the durability of the pavement.The steel girders are fabricated in small segments in factory,assembled by large segments at site and then pushed longitudinally to the designated spots.