Damage Assessment and Repair Design and Implementation for Underpass Bridge Based on Fire Effects

Fire effects cause one span of a frame underpass bridge in Harbin large area of different levels burning. Among them, some parts burned seriously; many adjacent beams turn black at bottom of roofs; parts of railings burned out of shape; parts decoration of side wall fractured, which blocked traffic towards Harbin. In order to make safety, repair on time, recovery traffic as soon as possible, satisfy the rules of original design and save money, this paper uses high strength non-shrinkage grouting material to repair stiffness of crack and damage concrete and carbon fiber to improve structure carrying capacity. Also, it uses middle support technique to reinforce the underpass bridge when repairing. Through a comparative analysis before and after reinforcement, paper confirms the feasibility and reliability of this repair design.