变截面连续梁整体顶升技术在桥梁改建中的应用

Application of Integral Jacking Technology of Continuous Beam with Variable Section in Bridge Reconstruction and Expansion

广中江高速东凤互通主桥跨既有公路设计为39 m+60 m+32 m钢筋混凝土连续箱梁,因设计方案变更,需对已施工完成的梁部进行整体顶升并接高墩柱。为解决该桥因顶升高度高、跨度不对称、桥梁宽度渐变给顶升带来的困难,该桥梁施工中通过“先转角、再顶升”的施工方法,在主千斤顶与跟随千斤顶同步作用下,通过千斤顶顶端可转球头、盖梁限位柱等一系列保障措施,解决了连续梁顶升水平位移、转角及内力控制的难题,并总结形成一套成熟的施工技术。顶升完成后经复测,桥梁内力及线形均符合设计要求。

The main bridge of Dongfeng interchange of Guangzhou Zhongjiang expressway is designed as 39 m+60 m+32 m reinforced concrete continuous box girder across the existing highway.Due to the design scheme change,it is necessary to lift the completed beam and connect the pier column.In order to solve the difficulties caused by high jack up height,asymmetric span and gradual change of bridge width,the horizontal displacement and angle and internal force control problems of continuous beam jacking are solved by using the construction method of "first corner and then jacking",under the synchronous action of main jack and follow jack,and through a series of guarantee measures,such as the rotatable ball head on the top of jack and the capping beam limit column.Moreover,the formation of a set of mature construction technology is summed up.After the completion of jacking up,the internal force and line shape of the bridge meet the design requirements.