Abstract
This paper has done continuous on-site experimental researches on temperature field and temperature effects that are under the influence of hydration heat of concrete during the molding process of dumb-bell CFST arch bridge. Analysis on time-history law of temperature field and temperature effects is made. Results reveal that temperature variation of hydration heat of the concrete within the steel tube is showed as follows: temperature rising-continuous high temperature—temperature dropping—equalizing. The structural temperature field, generated under the effect of hydration- heat in the process of molding arch rib, is nonlinear temperature field. Temperature field of concrete hydration heat has an obvious effect on crown section. Finally, practical methods to calculate the closure temperature of CFST arch rib and the effective measures to reduce the residual internal stress of temperature of arch rib are proposed.
Highlights
Concrete-filled steel tube (CFST) arch is a stress structure composed of steel tube and concrete
The structure temperature field caused by hydration-heat in the process of molding concrete-filled steel tube is nonlinear temperature field, namely, besides the whole temperature variation, the structure brings about section temperature difference
The effect caused by concrete perfusion of top chord on steel tube of arch foot section fluctuates slightly, but the concrete perfusion of bottom chord has little influence on the tube, namely, temperature effect on the steel tube of arch foot is not obvious
Summary
CFST arch is a stress structure composed of steel tube and concrete. CFST arch bridge is different from steel arch bridge,concrete arch bridge and masonry arch bridge in various aspects, such as materials and composition of the rib, section size and construction methods etc. Lin Chun Jiao and Zheng Jielian et al [4] foster a calculation analysis on the temperature field affected by hydration heat of circular and arch ribs of dumbbell-shaped section respectively. Research shows that when concrete reaches the intensity of shaping into CFST structure, certain thermal-stress is accumulated in the structure under the influence of hydration heat, which will affect the temperature effect of molded structure. 180 The Open Civil Engineering Journal, 2011, Volume 5 distribution regularity of hydration heat temperature field and its effects of CFST arch bridge.
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