Temperature Effects and Calculation Method of Closure Temperatures for Concrete-filled Steel Tube Arch Rib of Dumbbell-shape Section

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.