中马友谊大桥引桥下部结构优化设计  

Optimization Design of Substructure of Approach Bridge of China-Maldives Friendship Bridge

作　　者：侯鹏飞[1] 肖海珠[1] 李华云[1] 刘小林[1] HOU Peng-fei;XIAO Hai-zhu;LI Hua-yun;LIU Xiao-lin(China Railway Major Bridge Reconnaissance&Design Institute Co.,Ltd.,Wuhan 430056,China)

机构地区：[1]中铁大桥勘测设计院集团有限公司,湖北武汉430056

出　　处：《世界桥梁》2018年第5期17-20,45,共5页World Bridges

摘　　要：中马友谊大桥引桥为跨度30m预应力混凝土I形梁桥,浅水区引桥1号~3号墩原设计方案为"T形"大悬臂墩,通过高度为2.5m的矩形承台与4根直径1.5m钻孔灌注桩相连。承台施工需开挖礁灰岩厚度5.1~6.1m,施工效率低、破坏珊瑚礁、扰乱海洋生态环境。优化后方案取消了承台结构,采用桩柱式桥墩,桥墩与直径2.0m桩基直接相连,2个墩柱的横桥向中心间距为9m。利用空间有限元软件,分析墩高对桥墩和盖梁受力特性的影响。计算结果表明,当墩高在4.7~6.2m范围时,桥墩各构件受力更为合理。优化后的桩柱式墩在外观上与原设计相似;避免设置承台结构,减少开挖礁灰岩,有效地保护了环境。The approach bridge of China-Maldives Friendship Bridge is a prestressed concrete I-shaped bridge with typical span length of 30 m.The piers of approach bridge from No.1 to No.3 in the shallow water area are originally designed as T-shaped piers with long cantilevers,to which the pile caps are rectangle-shaped,2.5 m in height and the foundation is formed of 4,φ1.5 m bored piles.However,during the construction of pile caps,the excavation depth in the reef limestone reaches up to 5.1~6.1 m,which would result in lower construction efficiency,damages to coral reefs and disturbance to the ocean ecological environment.After optimization,the piers are changed to be columned piers without pile caps,directly resting on the pile foundation that is 2.0 in diameter.The center-to-center transverse distance between two pier shafts is 9.0 m.The impact of pier height on the load bearing capacity of the pier and cap beam was analyzed by using spatial finite element software.The results of the calculation show that the load bearing condition of each components of the pier becomes more rational when the pier height is within the range of 4.7~6.2 m.The columned piers after optimization keep consistency with the shape of the original design and no pile caps are added,which reduces the excavation amount of the reef limestone and effectively protects the environment.

关 键 词：预应力混凝土结构 珊瑚礁地质 下部结构 桩柱式墩 优化设计 有限元法 

分 类 号：U443.2[建筑科学—桥梁与隧道工程] U442.5[交通运输工程—道路与铁道工程]