实现整孔架设的48 m UHPC简支箱梁设计

The implementation of design for integrally erected 48 m UHPC simple-supported box girder

提出一种设密集横隔板的整孔预制架设48 m UHPC简支箱梁桥新方案。该方案将超高性能混凝土(UHPC)、密集横隔板薄壁箱梁和预应力钢束有机结合,不仅提升了预制架设简支箱梁的跨径,而且消除了传统大跨径简支PC梁桥的抗裂性差、残余徐变变形难控制的问题。通过对跨径48 m UHPC简支箱梁试设计和分析,结果表明:该方案箱梁各板件厚度大幅减小,箱梁吊装重量与32 m跨常规PC箱梁相当,具有良好的经济性;主要计算结果均能满足规范要求;密集横隔板有效降低了箱梁的横向应力、扭转变形以及截面畸变。整孔预制架设48 m UHPC简支箱梁桥是一种在安全、经济、耐久各方面具有竞争力的梁桥新方案。

A novel integrally prefabricated and erected 48 m ultra-high-performance concrete （UHPC） simple- supported box girder bridge with dense diaphragm plate was proposed.By combining UHPC, thin-walled box gird-er with dense diaphragm plates and external prestressing into the novel box-girder scheme, not only can the span length of prefabricated and erected simple-supported box girder bridges be improved, but also the ever existing problems in long-span simple-supported PC bridges,such as the cracking in concrete girders and the excessive residual creep deflection at midspan, may be eliminated. A trial-design and analysis for a simple-supported box girder bridge built from UHPC with span length of 48 m is presented, and the results show that the thicknesses of its components can be decreased greatly,the self-weight of superstructure may be equivalent to that of a 32 m PC simple-supported box girder, a good economy may be achieved. And all of the main calculation results comfort code requirements. Besides, the transverse stress,the torsional deformation and the cross section deformation de-creased effectively by using the dense diaphragm plates.