FLEXURAL STRENGTHENING OF TWO-WAY SLABS USING FRPs

摘要

Strengthening of two-way slabs using Fibre Reinforced Polymer (FRP) materials is presented. The behaviour of two-way slabs strengthened in flexure is discussed. Carbon FRP strips and glass FRP laminates can be used to increase the flexural capacity of two-way slabs to an average of 36% over that of the reference (un-strengthened) specimen. An increase of the initial stiffness was achieved for flexural specimens; however, an apparent decrease in the overall ductility was evident. A finite element analysis of the flexural-strengthened two-way slabs is also discussed. An incremental elastic-plastic concrete model is implemented. In compression, the concrete model is elastic until a yield point is reached after which irrecoverable plastic strain exists. Pre-cracking and post-cracking behaviours of concrete are considered in the study with special emphasis on the impact of the FRP materials on the concrete fracture energy and hence on the concrete tension stiffening. A full bond is assumed between concrete and the steel and FRP materials. The comparison between the finite element analysis results and the experimental results shows a good agreement.