Bridge Reinforcement

Project Overview

A bridge project was built in 1971. The overall length of the bridge is about 239.15m, the width is 12.1m, a total of 16 holes, and the aperture is about 13.9m. The upper structure of the bridge project is a T-beam, and the lower structure is a pile-column abutment. Due to the long construction time of the bridge, combined with the perennial vehicle load, the bridge has appeared various degrees of disease. At the same time, the width of the bridge cannot meet the increasing demand for vehicle travel, and the bridge needs to be widened and strengthened. After comprehensive analysis, it was finally decided to use carbon fiber to reinforce the T-beam. After testing and testing, the reinforcement effect was good.

Carbon fiber reinforcement construction plan

The flexural reinforcement plan for the main beam of the bridge’s T-beam uses 18×1800 (cm) and 18×400 (cm) carbon fiber sheets to press on the bottom of the main beam under the mid-span beam, and set a 12cm width at both ends of each layer. The U-shaped hoop is used to fix the carbon fiber sheet.

Shear strengthening scheme for main girder of bridge t-shaped beam

The reinforcement position is determined at the position close to the fulcrum diaphragm, and a U-shaped outer hoop with a width of about 20cm is added, and a main beam is set with 12 channels. The position of the web at the end of each main beam uses a U-shaped transverse outer hoop with a width of about 20 cm.

Carbon fiber reinforcement construction process

In the widening and strengthening of the bridge project, the carbon fiber reinforcement process was strictly followed. Clean the surface of the beam member → further clean the substrate → apply the mixed paint to the bottom layer → scrape the substrate flat → carefully paint a layer of impregnating resin → paste the fiber sheet on the position that needs reinforcement → then apply a layer of impregnated resin → do the follow-up maintenance work → paint the protective material.

Comparative analysis of carbon fiber reinforcement

After the completion of the bridge reinforcement, after testing, it is found that the dynamic and static load data of the bridge have been significantly improved, and it has played an extremely effective role in reinforcement.

It can be seen from this case that the carbon fiber reinforcement technology is simple to operate, does not require large-scale equipment and machinery, and only needs to use small electric tools. The number of operators is small, the construction efficiency is high, and the cost is low. And there is no need to interrupt the traffic, the impact of the construction environment is relatively small, the construction period can be significantly shortened, and the social and economic benefits are very significant. At the same time, the construction technology can significantly increase the service life of the building, and the reinforcement cost is low.

Compared with reinforced concrete reinforcement, the cost of carbon fiber reinforcement may be slightly higher, but the overall construction period is shorter and the total cost is still lower.

Therefore, carbon fiber reinforcement is very suitable for bridge engineering where the body of the bridge is slightly damaged, the construction period is high, the traffic flow is large, and the traffic is not suitable for traffic interruption. At the same time, it is very friendly to the repair of bridge cracks. If the bridge structure is severely damaged and large-scale concrete fragmentation occurs, it is necessary to use the reinforced concrete reinforcement method to increase the section. This method has a long construction period and needs to interrupt the traffic.

Concluding remarks

Carbon fiber reinforcement technology has a wide range of applications in bridge reinforcement projects, its construction operation is convenient, the construction period is short, and the reinforcement effect is excellent. Therefore, it is necessary to use carbon fiber reinforcement technology reasonably in the reinforcement of bridge engineering. In actual construction, it is necessary to select carbon fiber reinforcement materials, and carry out construction operations in strict accordance with the construction process, and do a good job of maintenance treatment to ensure that the project achieves the expected reinforcement effect.