Reinforcement and Repair of a Fire Damaged Bridge

The total length of the bridge is 1158.06m, and the total width of the bridge deck is 17 25m, with a bridge width combination of 0.5+15.75+1.0m. The upper structure is a prefabricated prestressed concrete T-beam with a length of (17 * 30+1 * 40+20 * 30) m, with 7 beams horizontally arranged and plate rubber bearings; The substructure consists of reinforced concrete multi frame abutment, reinforced concrete double column pier, and reinforced concrete bored pile foundation; The bridge deck pavement is of asphalt concrete structure, and the expansion joint is a Muller expansion joint.

Disease analysis:

The fire caused severe burns to the main load-bearing parts of the T-beam, diaphragm, cap beam, and pier columns of the second span on the left side of the bridge. The concrete peeled off in multiple places, the steel bars were exposed, and the T-beam had significant deflection and deformation, resulting in ductile failure.

Main reinforcement plan:

1. Considering the large area of the damaged area caused by excessive fire at the bottom of the board, conventional epoxy mortar repair did not achieve the effect of improving bearing capacity. Therefore, the carbon fiber mesh reinforcement system was ultimately chosen for overall reinforcement of the damaged area caused by excessive fire;

2. For T-beams with large deflection deformation and ductile failure, prestressed carbon fiber plates are arranged at the bottom of each beam to reinforce the three T-beams in bending;

3. Enlarge the section of the pier column and use bonding steel or other methods to add damaged diaphragms