Finite Element Modeling of Retrofitted RC Beams

Abstract

ABSTRACT Many structures damaged due to increasing load, earthquake and many other natural disasters, toxic emitted in the surrounding area and to rectify these structures, repair and rehabilitation has become an increasingly important challenge for the reinforced cement concrete structures. Upgrading structural load deformation capacity is a substantial part of the rehabilitation and retrofit of reinforced cement concrete components is now becoming a mainstream. As a combined result of structural rehabilitation needs, strengthening and retrofitting of concrete structural parts and now-a-days it becomes the major growth research area for the researchers. Amongst various methods developed for strengthening, the deflected parts of the structures and retrofitting of reinforced concrete (RC) beam structures, external bonding of fiber reinforced plastic (FRP) wrapping on to the beam has been widely accepted as an effective and convenient method. In particular, the flexural strength of a beam can be significantly increased by application of FRP sheets adhesively bonded to the beam tension face. The main advantages of FRP include high strength and stiffness, high resistance to corrosion, as well as light weight due to low density. The retrofitting can be applied economically, as there is no need for mechanical fixing and surface preparation. Moreover, the strengthening system with FRP can be easily maintained by finite element method. The finite element method has thus become a powerful computational tool, which allows complex analyses of the nonlinear response of RC structures to be carried out in a routine fashion. With this method the importance and interaction of different nonlinear effects on the response of RC structures can be studied analytically. The study deals with “Finite Element modeling of the Retrofitted RCC Beams” with the help of ATENA. The ATENA is new FEM based software which helps in FEM modeling the RCC structure. In this research, the first phase is to FE modeled the beams and analyze the results and also compare the results of stressed retrofitted beams with the control beam. The four simply supported half beams are modeled due to symmetry. Out of these beams, one beam was taken as control beam and other three beams were stressed at 60%, 75% and 90% of the ultimate load and after the stressing beams, they are retrofitted by using the GFRP sheet. Initially, the control beam was modeled in the ATENA and analyze. ATENA gave the load deflection curve, the ultimate load and the ultimate deflection, stress strain values, cracking behavior at each steps etc. After getting the ultimate load and the ultimate deflection of the control beam, the other three beams are modeled one by one and stressed to their respective loads and then retrofitted modeling is done in ATENA. When all the stressed retrofitted beam are modeled, start analyze all three beams. All the results of the stressed retrofitted beams are collected and compare with the control beam results. The results showed that stressed retrofitted beam has higher ultimate load deflection than the control beam. The second phase of this research is to compare the results with the experimental results and try to identify the various effects on the RCC structural members. The results show good agreement with the experimental results. Only the control beam, analytical results showed some difference from the experimental results whereas the stressed retrofitted beam, analytical results show nearly the same results as experimental results.