Experimental Study On Reinforcement Concrete Beams Strengthened With Fiber Reinforced Polymer Laminates

Externally bonding fiber reinforced polymer(FRP) laminate to reinforced concrete structure is a new strengthening method which emerged in 1990s. Carbon fiber reinforced polymer(CFRP) laminate and glass fiber reinforced polymer(GFRP) laminate are used widely. Because two of them have each advantages as following: CFRP laminate has very high intensity, GFRP laminate has good ductility and cost low. It is necessary to study the performance (such as flexural capacity, crack and deformation) of the members which strengthened with these two high intensive materials.The article has tested on 8 reinforced concrete simple beams which strengthened with various FRP laminates and under different load history condition. The experiment results indicated that the flexural capacity and stiffness of strengthened beams would enhance in any extent, the crack width would reduce. Three destroys modes are observed in the experiment, such as concrete crushing, FRP laminate snapping, glue-concrete interface bonding failure. In order to achieve preferable strengthened effect, construction quality and enough anchor measure must be strictly ensured.Experiments were carried on 11 reinforced concrete continuous beams which strengthened with FRP laminates. The experiment results indicated that the cracking load, the yielding load, the ultimate load all have remarkable enhance, in which the flexural capacity enhances obviously, the reinforcement effect is obvious. Crack of continuous beams strengthened with FRP laminates appears slightly late than that of ordinary concrete continuous beams, the crack development is slow, and crack interval and crack width are relative small. The ductility of continuous beams strengthened with GFRP laminates would enhance, and the internal force redistribution effect would relative sufficient than that of continuous beams strengthened with CFRP laminates.The article confirms the serviceability, the reliability and the accuracy of the flexural capacity formula, through the massive tentative data of reinforced concrete beams strengthened with FRP laminates. And the internal force redistribution of continuous reinforced concrete beams strengthened with FRP laminates were analyzed in the article.