Deflection for Pre-Stressing Concrete Thin-Wall Box Girders Bridge under Action of Multi-Span Loads Exposed to Fire

Abstract

The deflection for pre-stressing concrete thin-wall box girders bridges under action of multi-span loads exposed to fire was presented in this paper. Based on thermal and mechanics parameters, the fire and load model was designed, the space analysis procedure was performed to analyze the maximum deflection of each span during prophase and anaphase of extending-fire time, altogether 4 kind of load case. The studied results indicate: under condition of the whole span fire and load model of multi span, the mid-span deflection of the second span is down-warping during the fire prophase which its time is about 20 minutes, and up-warding or horizontal during the fire anaphase which its time is about 50 minutes; the deflection of the first and third span is down-warping with extending time during the whole fire time.