Prediction of confined compressive stress in rc columns strengthened with CFRP using fuzzy logic approach

A major part of Turkey is located on active seismic zones and 95% of Turks live in these areas. Because of the population growth and also internal migration, large building stock vulnerable to seismic activities arises around Turkey. After 1999 earthquake, Turkish Seismic Design Code (TSC, 2007) which has been updated for the seismic rehabilitation of buildings has become more stringent, especially for existing RC structures. There are several strengthening/repair techniques and materials in literature. Although the method of strengthening concrete structures with fiber reinforced polymers (FRP) is a relatively new technique, it has existed for over a decade. Much focus and effort has been placed on understanding the behavior of FRP confined concrete structures. In this context, several confinement models have been developed for FRP?confined concrete for the prediction of stress-strain behaviour. Several researchers have developed various constitutive models to measure the increase in the axial strength of concrete due to the confinement effect of FRP laminates. In Chapter 1, a brief literature review has been given and clear aims and objectives for the current Thesis have been identified. In Chapters 2 and 3, RC rectangular columns wrapped with cabon fiber reinforced polymers (CFRP) considering several confinement models in the literature have been investigated. In chapter 4, general information about the artificial intelligence-based algorithm has been given. In chapter 5, based on the experimental data set, a new artificial intelligence-based algorithm has been implemented in order to predict confined compressive stress in RC columns strengthened with CFRP using fuzzy-logic methodology, and non-linear regression analysis-based modeling have also been conducted. Analysis results have been compared with the outputs of the empirical equations proposed for the stress-strain relationship for rectangular RC columns confined with CFRP jackets under axial compression.