Study On Flexural Strengthening With CFRP Materials And Its Application In Highway Bridges

Structural retrofit and rehabilitation with Carbon Fiber Reinforced Plastic(CFRP) is a very hot strengthening technique which has a great market in highway bridges,but it is still in unformed phase. The paper is based on the scientific project from Zhejiang Provincial Communication Department named 'Research on the technique of structural retrofit and rehabilitation of slab-beam type RC bridges with hollow or solid body'. First, the theory and its developing process is summarized. Then,in order to understand the flexural performance of RC beam retrofitted with CFRP sheets, test of 4 RC beams was carried out. Studies on interfacial debonding or concrete cover separation failure of RC beams strengthened with CFRP sheets has made and it provides some basic references for people to ensure the CFRP-strengthened beams against these premature failures. Finally, according to the bridge situation of Huzhou city Zhejiang province, two typical highway bridges were chosen to make study. One strengthened with steel plate and the other was strengthened with CFRP sheets. By doing so,it can choose a economical, reasonable strengthening technique for this type highway bridges from all kinds points.Load test before and after reinforcement shows that the two reinforcing method can enhance capacity effectively and improve the stiffness of the structure. Compared with the traditional strengthening techniques, The CFRP reinforcing method has great advantages in strength and efficiency, convenience in construction, good durability and corrosion resistance, extensive fields of application, low deadweight, no influence on traffic and hardly changing the space under bridge. At the same time, as the costing decreases, economical advantages of CFRP reinforcing emerge gradually.In conclusion, the paper is based on the experimental and theoretical analyzing results of flexural strengthening RC beams. And then combined its application in highway bridges, The method of structural retrofit and rehabilitation with CFRP was summarized from strengthening design, retrofitting construction, strengthening effect, economy analyse and application market. All these is valuable for strengthening engineering application of the CFRP reinforcing method and it can provide some reference for people who want to advocate this strengthening technique in highway bridges.