Experiment and analysis on fire resistance of two-span prestressed concrete continuous beams

To research the fire resistance of prestressed concrete (PC) continuous beams, experiments on fire resistance of 9 two-span bounded PC continuous beams were completed. Temperature distribution along the section of beams was obtained by embedded thermocouples in the beams. Test result measured by displacement sensors on the beams indicates that the increase speed of the deflection of beams is kept the same in fire. Test result measured by load cells at the side supports indicates that side supports reaction decreases rapidly by heating within 10 minutes; when undergoing fire over 10 minutes till 40 minutes, side supports reaction changes slightly; after that the side supports reaction begins to recover rapidly. During the fire, the whole process of water overflowing, vapor appearing and developing, as well as water drying and vapor disappearing occurs on the unexposed surface. Calculation formula of side support reaction and deflection in the mid-span of beams subjected to fire were obtained by fitting curves of experimental data considering each key factor.