厄瓜多尔国家联合大桥设计与技术特点

厄瓜多尔国家联合大桥主桥长1 975m,由单跨跨径75m的3联预应力连续箱梁结构组成。下部结构采用低阻低冲刷裙边空心箱板尖角承台,结合4根直径2.5m的支撑摩擦桩和倒八棱台实心墩柱为一刚度整体;上部主梁采用单箱单室两向预应力体系,重量均匀,结构简约,满足桥梁节段预制与拼装快速高质施工的要求;利用桩土弹性作用协调部分梁墩固结桥跨变形,同时采用铰接段克服长联主梁收缩与徐变、温差和地震产生位移带来的影响;设计预留体外预应力束调整营运期的挠度。

Design and Technical Characteristic of National Unite Bridge in Ecuador

The main bridge of National Unite Bridge in Ecuador is 1 975 m long,composed of three continuous units of prestressed box beam structures with individual spans each of 75 m in length.The substructure is a rigid whole formed of a hollow box plate cusp cap with low resistance and low erosion skirt,four 2.5 m friction piles and an inverse octagonal solid pier shaft.While the main beam exploits single cell single box two-way prestressing system,which has uniform weight and concise structure,satisfying the requirements of rapid prefabrication and assembling of beam segments with high quality.The deformation of the bridge spans with girder-pier fixed connection is adjusted by the pile-soil elastic interaction.Meanwhile,hinged section are arranged to overcome the impact of displacement caused by beam shrinkage and creep,temperature variation and earthquake.In addition,future external prestressing tendons are designed to adjust deflection of the profile in service period.