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Date of Award
Civil and Environmental Engineering
DURABILITY PERFORMANCE OF FRP STRENGHTENED CONCRETE BEAMS AND COLUMNS EXPOSED TO HYGROTHERMAL ENVIRONMENT
ABULGASEM M. ELARBI
Advisor: Dr. Hwai-Chaung Wu
Major: Civil and Environmental Engineering (Structural Engineering)
Degree: Doctor of Philosophy
Concrete structures deteriorate over time due to exposure to various environments, including hot and humid weather. High temperature, wind, and air humidity in many hot climates can all have a negative impact on the performance of concrete structures. The most important factors are temperature and humidity - often times these effects are not immediately evident and develop years later - making determination of responsibility difficult and repair expensive.Fiber reinforced polymer (FRP) composites have been recognized as a viable material for strengthening/retrofitting deficient structures, due to their superior performance. FRP sheets/fabrics are usually bonded to existing reinforced concrete structures. Due to their high specific strength/stiffness and lightweight, these materials can offer significant advantages over more traditional materials such as concrete and steel.
The present investigation intends to study the effects of changing hygrothermal conditioning cycles (either by changing relative humidity and temperature is kept constant, or by changing temperature but relative humidity is maintained same) on the durability performance of FRP strengthened concrete beams and columns. The study include the long term influence of moisture, high temperature, and combined hygrothermal conditions on the mechanical properties of FRPs composites and the effect of deteriorated composites on the structural behavior of concrete beams and columns when subjected to realistic environmental conditions. This study includes also the study of the fracture behavior between concrete and external FRP strips in hygrothermal condition. The overall approach consists of experiments, analysis, and computations.
An extensive experimental research has been done throughout implement and test several sets of specimens include epoxy beams, concrete beams and columns, and FRP strengthened concrete beams and columns exposed to different environmental conditions. Carbon and glass fiber reinforcement polymer with resin material were provided from two different resources have been utilized in this study.
Also, two and three-dimensional extended finite element method (X-FEM) is developed and implemented in the ABAQUS-CAE package to predict the bond strength at the interface between concrete and FRP strengthening fabric.
In addition, analytical calculations for epoxy beams, non-strengthened concrete beams, and columns, FRP strengthened beams and columns were developed based on the ACI 318 and ACI 440.2R-02 including the environmental effects based on the temperature dependent factor.
Elarbi, Abulgasem Mohamed, "Durability performance of frp strenghtened concrete beams and columns exposed to hygrothermal environment" (2011). Wayne State University Dissertations. Paper 307.