Bridges Strengthening And Repair

Introduction to project examples

The second line project of a northwest railway extension has a total length of 110km. The planned route involves the reconstruction and reinforcement of multiple culverts and bridges. Among them, there is a 19m reinforced concrete frame bridge with 2 holes, which crosses the nearby expressway at an angle of 56 degrees, and at the same time it crosses a single-track railway at an angle of 28 degrees.

It is expected to rebuild a bridge across the highway on the right side of the bridge. Due to the construction period and cost factors, after on-site exploration and calculation, it is expected that the bridge frame must be reinforced to meet its two-lane traffic demand.

In this project, Horse unidirectional carbon fiber sheets and epoxy resin adhesive are used as reinforcement materials for bridge. In this way, the bearing capacity of the reinforced concrete of the bridge is improved, and the tensile strength of the bridge structure is enhanced. In this way, the strength, stiffness, and crack resistance of bridge components are fully optimized, and the stability and quality of the bridge engineering are guaranteed to meet the requirements of the opening of the line.

Selection of bridge reinforcement and repair materials

The selection of reinforcement raw materials is the primary technical process in the construction of carbon fiber sheet reinforcement for bridges. The reasonable and accurate selection of its materials will directly determine the effect and quality of bridge reinforcement. Because the excellent mechanical properties of carbon fiber sheet are closely related to its material and weaving process, the selection should be based on the following two factors.

1) The homogeneity of carbon fiber materials. Only when the overall arrangement of the carbon fiber bundles is consistent with the work, can the woven carbon fiber sheet exhibit the characteristics of uniform force on the whole, and avoid the problem of carbon fiber filament breakage caused by uneven force. Therefore, in the selection of raw materials, the use of materials with poor homogeneity should be avoided first. Prevents the problem of uneven stress on various parts of the carbon fiber sheet due to the stress of the bridge components, which makes it difficult to exert and apply the reinforcement effect.

2) Carbon fiber sheet resin content. The carbon fiber sheet used in the bridge reinforcement operation of this project contains pre-impregnated resin, and its resin function is to restrain and bond the carbon fiber to each other to form a complete force-bearing whole, thereby improving the actual reinforcement effect of the carbon fiber sheet. However, if the prepreg resin content is too high, not only the reinforcing ability of the carbon fiber sheet cannot be improved, but also the penetration effect of the resin in the bonding process will be affected due to the excessively high content of the prepreg resin. This will affect the reinforcement quality of the concrete structure and endanger the safety of bridge engineering.

In accordance with the influence of the above-mentioned material selection factors, combined with the actual conditions and requirements of the bridge project, after multiple comparison tests, HM-20 carbon fiber sheet and matching adhesive glue are finally selected as the raw materials for reinforcement construction.

Concrete construction technology of strengthening bridge with carbon fiber sheet

Explore the specific construction process of this bridge reinforcement project as follows:

Demolition of the bridge deck waterproof layer

Coarse and hemp treatment of bridge deck concrete

Concrete section repair treatment

Use resin primer for painting

Use leveling glue for painting

Use adhesive glue to stick HORSE carbon fiber sheet

Make bridge reinforced concrete reinforced protective layer

Inspection and review of construction quality

Concluding remarks

To sum up, with the passage of time for the completion of existing construction projects, the need for reinforcement of concrete bridge structures is increasing, and it has become an operation project that construction units need to pay close attention to. Among them, carbon fiber sheet has a better repair and reinforcement effect in the reinforcement construction of bridge components, and is easy to operate and easy to construct. It is suitable for application and promotion in various types of bridge reinforcement projects. To promote the consolidation and optimization of the reinforced concrete bridge structure, to ensure its quality, safety and traffic efficiency.