INVESTIGATION ON CONSTRUCTION QUALITY INDICES FOR PC CONSTINUOUS BOX GIRDERS
Based on three bridge dismantlement, several construction quality indices were investigated in-situ ,which consisted of duct grouting density of prestressing tendons, percentage of concrete surplus in box girder, concrete protection layer thickness ,etc. These indices were analyzed statistically to find out the construction quality of PC box-girders in China. The investigation result indicated that the percentage of concrete surplus of PC box-girders, constructed by the free cantilever method, was generally high and varied between 10% to 20%. And it was found that ,in general, the concrete surplus centred at the top slab and bottom slab of box girder. The duct for prestressing tendons were only partially grouted, with over 50% ungrouted for longitudinal tendons and over 70% ungrouted for transverse tendons. Obviously, this increased the prestress loss in the tendons. In the another hand, the true calculating example in this paper indicated that concrete surplus and loss of prestressing will enlarge the principal tension stress in the PC box-girder, and would increase the possibility of structure cracking. The quantitative indices proposed in the paper is helpful in understanding the underlying reason for cracking and over flexing in the PC box girder ,and it also provided the important basis for structural analysis of PC box-girders.
Bridge engineering construction quality investigation concrete boz girder duct grouting concrete surplus
Wen-Qing Wu Bo Li Qun-Hua Xie Xiao-Gang Chen
School of Transportation,Southeast University,Nanjing 210096,P.R.China Zhejiang Provincial Plan Design & Research Institute of Communications,Hangzhou 310006,P.R.China
国际会议
长沙
英文
412-417
2009-10-26（万方平台首次上网日期，不代表论文的发表时间）