ULTIMATE STRENGTH OF CONCRETE CORBELS WITH HYBRID REINFORCEMENT AND STRENGTHENED EXTERNALLY BY CARBON FIBER

الملخص

The purpose of this paper is to establish a finite element model using ANSYS computer program version 15 that is capable of interpreting the use of internal hybrid reinforcement (consisting of combined CFRP bars and ordinary steel bars) in concrete corbels as well as the possible use of CFRP sheets for strengthening these corbels externally. It is aimed from such analysis to create small size corbels that are capable of resisting higher ultimate loads compared with ordinary R.C corbels. The validity of the proposed F.E model is checked by comparison with previous experimental results which exist for two separate cases. Namely the case of concrete corbels with internal hybrid bars but no external CFRP sheets; and the case of external CFRP sheets but no internal CFRP bars. The proposed F.E model having been verified through close agreement with the results of the existing experimental tests, it is then used to provide new data for estimating the ultimate capacity of concrete corbels containing both hybrid bars as well as external CFRP sheets. It is found that the ultimate strength of concrete corbels can be enhanced by 50% when both CFRP bars and CFRP sheets are used together in the corbels, and that only 30% strength enhancement can be obtained if CFRP bars or CFRP sheets are used separately.