At present, with the prosperous development of the economy and the rapid growth of the number of vehicles and the load capacity, the carrying capacity of highway bridges cannot withstand the load generated by the traffic flow, and even the overload of the bridge leads to serious traffic accidents. Therefore, the application of reinforcement measures for the lack of bearing capacity of expressway bridges is very important.

Reinforcement method for insufficient bearing capacity of bridge

Apply the stick-steel reinforcement method

(1) Reinforcement principle: chemical anchor bolts are implanted, and structural glue is applied between concrete members and steel plates, and the steel plates and concrete members will be effectively combined to form a whole to complete the goal of receiving forces together. In turn, the shear resistance and tensile capacity of the concrete members have been improved, and the bearing capacity of the bridge has been improved to a certain extent.

(2) Construction process: Carry out the base surface lofting work; implement drilling for the base surface; thoroughly clean up the impurities in the tunnel; implant anchor bolts into it. Steel plate blanking; sanding and derusting of the rusty part of the steel plate; cleaning of the grass roots; preparation of steel glue; sticking of the steel plate; implementation of anti-corrosion coating work.

(3) Precautions: The steel plate should be carefully polished to make it bright and natural, and the glue should be applied in sufficient amount and evenly, and there should be no hollowing.

CNF carbon fiber mesh reinforcement method

(1) Reinforcement principle: Using mortar as a carrier, with the help of the addition of carbon fiber mesh, it forms a new whole with the previous bridge in order to achieve the goal of common force. When the beam is under pressure, the tensile strength of the carbon fiber mesh will be used to enhance the shear resistance of the concrete member, thereby increasing the bearing capacity.

(2) Construction process: the base surface is chipped and cleaned; the mortar is configured according to a reasonable ratio; the bottom mortar is sprayed; the carbon fiber grid is laid; the surface mortar is sprayed; the leveling and finishing operations are done; the maintenance content is completed .

(3) Matters needing attention: The carbon fiber grid must be treated with a special coating first to meet the fire protection requirements and anchoring goals.

Prestressed carbon fiber plate reinforcement method

(1) Reinforcement principle: increase the pre-tension stress at the bottom of the beam. When the beam body is under pressure, the shear resistance of the beam body will be improved, and the beam body will have a more ideal bearing capacity.

(2) Construction process: stake out the base surface; base surface treatment; implement drilling and cleaning operations; implement planting reinforcement curing work; install the support. Apply special adhesive; install carbon fiber plate; tension prestressed carbon fiber plate; implement sealing anchor; surface coating for anti-corrosion.

(3) Precautions: In the process of strengthening the prestressed carbon fiber plate, the end support needs to be fixed. The center line of the tension end support and the carbon fiber plate support should be parallel or in the same straight line. It can ensure that the carbon fiber plate in the subsequent tension of the carbon fiber plate realizes the full cross-section force.

Insufficient bearing capacity of pier and abutment reinforcement method

Insufficient bearing capacity of the pier and abutment reinforcement method is to increase the pier and abutment section reinforcement method. Effectively increase the cross-sectional area of the pier and abutment and increase the transverse prestress to make it have stronger bearing capacity. The construction sequence of this form of reinforcement is: chiseling the concrete surface; positioning and lofting; finishing drilling and planting reinforcement; installing steel reinforcement. Install grouting pipeline; install template; apply concrete interface agent; pour concrete; perform maintenance work; install pre-stressed steel bar tension pre-stress; implement duct grouting operation; complete anchor sealing.

The key point of quality control is: the pre-stressed tension should be in full compliance with the set requirements, and attention should be paid to the combination of new concrete and old concrete surfaces. Some concealed places are very difficult to maintain due to water retention, so they can be cured by applying a curing agent.

Method to deal with insufficient bearing capacity of bearing

When dealing with insufficient bearing capacity of the support, the biased, cracked and damaged support needs to be replaced. The principles applied in the treatment process include: replacing biased, cracked, and damaged bearings to achieve reliable force protection for the upper and lower structures of the bridge, thereby increasing the bearing capacity of the previous bridge. The construction procedures are: arranging the jacks; carrying out jack test jacking; grading synchronous jacking to the height required for the construction; replacing the supports; implementing synchronous beam drop and cleaning the site.

The key point of quality control is: with the aid of the roof test, the synchronization of the jack and the monitoring displacement can be checked to avoid damage to the girder body and the bridge deck pavement due to asynchronization of the jacking.

Reinforcement method for insufficient foundation bearing capacity

The main form of reinforcement is to expand the foundation reinforcement method to repair the damaged foundation, which can effectively expand the bearing area of the foundation and make it have a stronger bearing capacity. The construction process is: driving the steel sheet pile cofferdam; digging out the soil in the cofferdam; draining the water existing in the cofferdam; making the concrete foundation; cleaning the site.

The key point of quality control is: the need to expand the foundation and the old foundation so that it can form an effective whole. The method used is planting steel bars or welding connecting steel bars.