EXPERIMENTAL STUDY ON SHEAR PROPERTIES OF REINFORCED CONCRETE (RC) AND PARTIAL PRESTRESSED CONCRETE (PPC) BEAMS STRENGTHENED WITH EXTERNALLY BONDED CFRP STRIPS
An experimental study and nonlinear finite element analysis including reinforced concrete(RC) beams and partial prestressed concrete(PPC) beams strengthened with CFRP strips were carried out under static loading.The influences of damage degree,ratio of shear span,stirrup ratio,and level of effective prestressing on the shear characteristics of these strengthened beams were investigated.Some important conclusions were extracted from the testing and numerical analysis and listed as follows: 1) The inclined cracking development can be effectively restrained using the proposed strengthening method with CFRP strips,and the shear load-carrying capacity and ductility of the strengthened RCPPC beams can be effectively improved.2) The synclinal cracking load,yielding loads of the stirrup,and the shear load-carrying capacity of RC beams strengthened after the damage would be enhanced while the ratios of shear span becoming smaller and stirrup ratio becoming larger.3) The improvements of shear carrying-capacity of PPC beams strengthened with CFRP strips would become larger if the level of effective prestressing increasing.4) The proposed nonlinear finite element(FE) model can better predict the shear performance of strengthened RCPPC beams,and the results from FE model can correlate very well with those from testing.5) The strength of CFRP strips should be effectively reduced during the shear strengthening design of the practical engineering cases.