ANALYSIS FOR SHEAR CAPACITY OF REINFORCED CONCRETE BEAMS WITH CORROSION STIRRUPS

In order to study the shear capacity degeneration of reinforced concrete(RC) beams with corrosion stirrups, considering the mass loss of the stirrup reinforcement, axial tensile tests were conducted on 48 naturally carbonation-induced corrosion plain steel bars embedded in roof concrete beams. The testing results indicate that the fracture section of corrosion steel bars is even without necking basically, and possesses a distinct brittle fracture character; also the yield point elongation of specimen shortens even disappears, and the limit deformation of specimens diminishes obviously with the increase of mass loss. By the regression analysis, a strength degeneration model of naturally corrosion plain steel bars is built. Considering the influence of steel bar corrosion on their cross-section and mechanical properties, as well as the reduction of the effective section area of the concrete, a shearing capacity assessment formula of RC beams with corrosion stirrups is proposed based on the shear capacity formula given by the actual Chinese code for the design of concrete structures(GB50010-2002). Finally, the proposed shear capacities of RC beams with corrosion stirrups are compared with the corresponding test results. The calculated results are shown to be in reasonable agreements with test ones.