Testing Analysis On Bending RC Slabs Strengthened With CFRP And Steel

Among methods of strengthening applied to one-way slab, Steel bonding and CFRP is very effective ones. WSTG anchor is only used to FRP. It is attempted to applied WSTG anchor to CFRP strengthening. CFRP has such overwhelming peculiarities as high stretch strength, high modulus, light weight, which provide it obvious priority to traditional styles of strengthening. So it has a brilliant prospect at the market. Debonding failure is the most serious problem of all, which retard the progress of CFRP strengthening. The damage of bond between CFRP and concrete leads to the debonding failure of specimens, when the stress of CFRP is at the low level. Besides applied to shear strengthening, U-strip can put off occur of debonding, which makes it the necessary part in CFRP strengthening. However the function of U-strip is limitative, and will debonb under higher load where shear cracks propagate. WSTG anchor which only applied to FRP, came into being in the past months. It is composed of top tooth, bottom tooth and lock device. FRP will never be pulled out, using proper radius and depth, even under very high load, when the anchor is locked. Stress concentration may not occur in the anchor. End debonding of CFRP is get rid of when the anchor is used to fix the end of CFRP. The paper is based on the experiment of flexural strengthening for one-way RC slab. The slab is 3m long, properly reinforced. Three styles used are as follow. First is to bond one lay of CFRP to the bottom of slab. Second is to bond strips of CFRP of proper width to the bottom with the end of CFRP is anchored by WSTG anchor. Third is to bond steel strips to the bottom with bolts at uniformly interval. The load system is statically one, and transfers load through two points to the slab. Use proper shear span, and specimens are all flexural failure. The paper puts concentration on the analysis of the strain of CFRP and stretch reinforcement at the middle point, and deflection of mid-span of specimen, makes a little study on the procedure of debonding. The specific influence of different strengthening styles to the flexural performance are discovered. It is initially realized to pre-stress CFRP strip by WSTG anchor. It is also known that the mechanics influence of WSTG anchor to CFRP under two positions of pre-stressed and not pre-stressed.