武汉鹦鹉洲长江大桥人字形钢-混叠合塔施工技术

Construction Technology of Herringbone Reinforced Concrete Composite Tower of Wuhan Parrot Island Yangtze River Bridge

武汉鹦鹉洲长江大桥2号中塔为国内首次采用纵向人字形钢-混叠合塔。下塔柱为钢筋混凝土结构,底节3m与承台混凝土一起浇筑;针对下塔柱截面尺寸大的特点,利用钢绞线作为模板拉杆。上段钢塔通过设置锚杆定位支架和限位装置、三向千斤顶等措施对T1节段进行精确定位;T1节段承压板下采取后压浆工艺,确保钢-混结合段密实、密贴;T3节段采用分块吊装、现场焊接技术;上横梁采用2节段无支架悬臂拼装技术。通过工厂预拼、现场测量和计算机模拟分析,提前对钢塔线形进行预控,并在调整接头设置合理的调整量,最终使钢塔安装线形满足设计和规范要求。

Herringbone reinforced concrete composite tower is used in No. 2 tower construction of Wuhan Parrot Island Yangtze River Bridge for the first time. The lower tower column is a reinforced concrete structure,the bottom segment with 3m and pile cap concrete are poured; according to the large section of the lower tower column,steel strand is used as a formwork rod. T1 segment is precisely located by setting bolt positioning bracket and limit device,three-direction jack and so on for upper tower; post-grouting technology is used under bearing plate of T1 segment,which ensures the reinforced concrete composite segment compact and close; hoisting block and on-site assembly technology are used for T3 segment; twosegment cantilever erection technology without bracket is used for the upper cross girder. Through the factory pre assembly,field measurement and computer simulation analysis,the shape of steel tower is pre-control in advance,setting a reasonable amount of adjustment in the adjustment of the joint. Finally,the linear control of the steel tower meets the requirement of design and specification.