Abstract

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Title:: Decay of rigidity for prestressed concrete T-shaped girder bridge exposed to fire

Author(s):: ZHANG Gang; HE Shuan-hai; LIU Yang; WANG Cui-juan; 1. School of Highway, Chang’an University, Xi’an 710064, Shaanxi, China; 2. Key Laboratory of Old Bridge Detection and Reinforcement Technique in Traffic Industry, Chang’an University, Xi’an 710064, Shaanxi, China; 3. Guizhou Provincial Transportation Department, Guiyang 550000, Guizhou, China; 4. School of Construction Machinery, Chang’an University, Xi’an 710064, Shaanxi, China

Keywords:: bridge engineering; multi-beam T-shaped girder bridge; prestressed concrete; fire hazard; rigidity; deflection variance

Abstract:: To study the decay of rigidity for prestressed concrete (PC) bridge with T-shaped girder under fire hazard, the relation equation between variance rate of deflection and decay rate of rigidity was given out, the coupled calculation model between decay rate of rigidity and deflection variance ratio was proposed, and the thermo-dynamics coupled calculation method was adopted to analyze the variance rate of deflection for PC T-shaped girder exposed to fire. Thus, the decay law of rigidity for PC T-shaped girder exposed to fire was disclosed. The results show that the temperature peak value is located at the corner of horseshoe part and web floor. Temperature at direct corner is higher than that at obtuse corner. Deflection variance ratio of single girder has a linear increment during the entire fire process. The variance rates of deflection of two girders and multi-girders have a quadratic parabola increment during the entire fire process. The variance rate of deflection for unilateral and continuous girder exposed to fire is greater than that for the same number and interval girder exposed to fire. With increment of fire time, the whole rigidity for PC T-shaped girder has a nonlinear increment when more girders are exposed to fire. The study is sensible to assessment for prestressed concrete bridge after fire hazard.