Study On Temperature Field & Temperature Effects Of Concrete Box Girder Bridge Constructed By Movable Scaffolding System

Effect of temperature is an extremely complex and great impact factor for concrete box-girder bridge, which has directly influence on security and durability of highway concrete box girder bridge. Sometimes, stress caused by loads of temperature is even higher than live loads, which are the reason why some PC bridges occur cracks. However, China highway and bridge criterions don't make detailed regulations about temperature gradient of PC box girder bridge. It is great theoretical significant and practical value to study on and discuss the real most adverse temperature gradient of PC box girder bridge. The objective of this paper is to present a further study and improvement of PC box girder spatial temperature gradient based on temperature observations on PC box girder bridge, in order to propose practical methods of temperature gradient and propose some suggestions and preferences about temperature gradient of PC box girder bridge for China highway and bridge criterion.In this paper, Guangzhou Pearl River Huangpu Bridge as background, the bridge is constructed by movable scaffolding system, the research on hydration heat of PC box girder during pouring and temperature gradient of PC box girder under solar radiation during construction is carried out, proposing the experimental study scheme of temperature gradient measuring and layout of thermometer sensor scheme, analyzing temperature gradient and its variations of temperature gradient of PC box girder bridge by large finite elements program ADINA, the results is confirmed by experimental study, proposing the vertical and horizontal temperature gradients and its expression of PC box girder under solar radiation in summer, which can represent Guangzhou region. On this basis, the effect of spatial temperature gradient is analyzed by finite elements program, the results show that tensile stress can reach 3.3Mpa at top plate lower margin of box girder under nonlinear temperature gradient, which should be paid attention. In this paper, further study on calculation of temperature stress of full-section temperature gradient obtained by horizontally translating vertical temperature gradient from China highway and bridge criterion, compared with results from spatial temperature gradient proposed in the paper, the results show that temperature effect can be estimated by using foil-section temperature gradient obtained by horizontally translating vertical temperature gradient from China highway and bridge criterion, besides the results is simply safety in practical engineering. At the same time, a practical calculation method of vertical and horizontal temperature gradient of PC box girder bridge that can represent Guangzhou region is proposed.