准朔铁路黄河特大桥设计建造技术

Design and Construction Technologies for Yellow River Super Long Bridge of Jungar-Shuozhou Railway

新建准朔铁路黄河特大桥主桥采用1-380 m钢管混凝土提篮拱,桥面标高受到线路纵断面控制,极端最高温度与最低温度温差达到65.6℃。对大跨度上承式钢管混凝土拱桥拱肋结构、拱上建筑、拱脚及基础型式、钢管混凝土温度影响、超大构件钢管拱架设等设计建造技术问题进行研究。主要研究结论:通过小矢跨比和拱顶刚架与梁式结构相结合的结构型式可适应线路纵断面标高受限难题;利用临时扣索能优化调整大跨度铁路钢管混凝土拱桥拱肋应力,节省用钢量;采用单、双榀相结合的吊装工艺可大幅减小缆索吊临时工程的规模;研制了抗拉强度达到7 MPa且适应顶升法施工工艺的钢纤维混凝土,解决小矢跨比大跨度钢管混凝土拱桥拱脚拱肋混凝土受力问题。

The 1-380 m concrete-filled steel tube basket-handle arch is adopted for the main bridge of the Yellow River Super Long Bridge on Jungar-Shuozhou Railway.As the bridge deck elevation is restricted due to the longitudinal profile of the track,the extreme maximum and minimum temperature difference is up to 65.6℃.This paper studies the technical issues of large-span deck-type concrete-filled steel tube arch bridge during design and construction,such as arch rib structure,spandrel structure,arch foot and foundation form,concretefilled steel tube temperature influence and erection of steel tube arch with super-large structural member;the paper also draws the following conclusions:the problem of restriction on the longitudinal profile elevation can be solved via adopting small rise-span ratio and the combination of arch crown rigid frame and beam structure;temporary fastening cable can be used to optimize and adjust the stress on arch rib of large-span railway concrete-filled steel tube arch bridge and save the steel consumption;the combined single-and double-truss hoisting technology can be adopted to greatly reduce the temporary project scale of cableway crane;the steel fiber reinforced concrete with tensile strength up to 7 MPa is developed,which is adaptable to the jacking construction technology and can cope with the stress at arch foot and arch rib of large-span concrete-filled steel tube arch bridge with small rise-span ratio.