Introduction to the project

The main bridge of Jiangsu S49 Expressway has a total deck width of 28 m and a bridge length of 634 m. It is a prestressed concrete continuous box girder with a design speed of 120 km/h. It was put into operation in 2008.

After 7 years of operation of the bridge, cracks appeared in the piled pier.

Tested by a professional testing agency, the reason is that there is no vertical bar or stirrup in the concrete at the top of the column, which is plain concrete. Without reinforcement, the cracks gradually develop and widen under repeated loads, and there is a risk of splitting the concrete on the top of the column, which in turn affects the safety of the superstructure.

After economic and technical analysis and comparison, it was decided to adopt the method of pasting carbon fiber sheet and outsourcing (sticking) steel hoop to the top area of the column for reinforcement to improve the bearing capacity of the pier.

Brief introduction of carbon fiber sheet and steel plate materials

Carbon fiber has the characteristics of corrosion resistance, tensile strength and light weight. It is a new building material that has been widely used in the reinforcement and reinforcement of bridges and the improvement of bearing capacity.

The steel plate reinforcement method is very popular because of its short cycle, flexible and variable bonding positions, no impact on traffic, and little use of space. The commonly used steel plate is Q235-B steel plate with good weldability.

Construction process

traffic control-construction preparation-concrete surface treatment-crack pressure grouting-ring pasting carbon fiber sheet-checking acceptance-steel plate lofting and processing-steel plate pasting-checking acceptance-anticorrosion treatment.

Conclusion

Expressway bridges need to be repaired and strengthened due to diseases caused by design, construction, management and operation. Among them, the reinforcement technology of bridges with carbon fiber sheet and outsourcing (sticking) steel hoop is widely used because of its many advantages. In order to close the cracks and limit the continuous expansion of the concrete cracks, sticking carbon fiber sheet on the surface of the structure is a recommended treatment. For more serious structural diseases, it is necessary to combine outsourcing (sticking) steel hoop reinforcement to achieve the rigidity, strength and stability of the bridge.