Rehabilitation of concrete highway bridges with CFRP composites

Foreword

The application range of CFRP composites reinforcement technology in bridge reinforcement engineering is very wide, which greatly repairs the diseases in bridge engineering and ensures the safety and stability of bridge engineering. Combined with examples, this paper analyzes the application of carbon fiber reinforcement technology in 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 T-shaped beams, and the lower structure is piled abutments. Due to the long construction time of the bridge and the long-term vehicle load, the bridge has suffered from 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, the carbon fiber reinforced T-beam was used, and after the test, the reinforcement effect was better.

Construction plan of CFRP composites reinforcement

The Bending Strengthening Scheme of the Main Beam of the T-beam of the Bridge

Use 18x1800 (cm) and 18x400 (cm) CFRP composites to press the bending moment under the main beam span center beam, and set a 12cm wide U-shaped hoop at each end of each layer. In this way, the CFRP composites is fixed.

Scheme of Shear Strengthening of Main Girder of T-beam of Bridge

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

Comparative analysis of CFRP composites reinforcement

After the bridge was strengthened  with CFRP composites, it was found after testing that the dynamic and static load data of the bridge were significantly improved, and played an extremely effective role in strengthening.

It can be seen from this case that the CFRP composites reinforcement technology is simple to operate, does not require large equipment machinery, and only requires the use of small power tools. The number of operators is small, the construction efficiency is high, the cost is low, and there is no need to interrupt traffic, and the impact on the construction environment is relatively small. Can significantly shorten the construction period, 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 CFRP composites reinforcement may be slightly higher, but the overall construction period is shorter and the total cost is still lower.

Therefore, CFRP composites reinforcement is very suitable for bridge projects where the body of the bridge is slightly damaged, the construction period is high, the traffic flow is large, and it is not suitable for traffic interruption. At the same time, CFRP composites reinforcement is also very friendly to the repair of bridge cracks. If the bridge engineering structure is severely damaged and a large area of concrete fragmentation occurs, the CFRP composites reinforcement method of reinforced concrete reinforcement should be used. This CFRP composites reinforcemnet method has a long construction period and requires traffic interruption.