Numerical analysis of Fracture behavior of CFRP Sheet–Strengthened notched Concrete Beams

The serviceability and safety of building and bridge structures may gradually degrade due to long term use, natural environmental deterioration, poor initial design and/or construction, increased design loads, extreme events such as earthquakes, and/or lack of maintenance. It is needed to use materials that are not susceptible to the same causes that trigged the deterioration in the first instance. Since the rebuilding of old infrastructure is very expensive and time consuming, cost-efficient and durable techniques of strengthening/rehabilitating are needed. There is a growing interest in the use of Fiber Reinforced Polymer (FRP) composite materials for the strengthening and retrofitting of concrete beams. Also it is too important to know the influence of effective parameters on the fractural behavior and strengthening of cracked concrete beams, so the present study is dedicated to numerical analysis of carbon fiber reinforced polymer (CFRP) sheet-strengthened notched concrete beams. The bearing capacity, CFRP debonding and crack mouth opening displacement (CMOD) of notched beams were evaluated with nonlinear finite element method. Numerical results have been compared with experimental results of other researches. After validation the numerical modeling of CFRP plated notched beams, parametric studies reveal quantitatively the effects of various factors such as; thickness of CFRP sheet, compressive strength of concrete, initial crack length and interfacial bond strength on the CMOD curve of mentioned beam, which is found to be characterized by two peak loads. The first and second peak loads increase with the increase in concrete strength, the thickness of CFRP sheet and the interfacial bond strength. It is also found that increasing the initial crack length decreases the first peak load but no exerts on the second peak load.