Reliability of load-Deformation Estimate for High-Strength Reinforced Concrete Beams

The applicability of methods, routinely used in Japan in evaluating the force-deformation relationship of normal reinforced concrete (RC) members, was examined for high-strength RC beams. The member end moment-rotation relationship was idealized into a trilinear relation with stiffness change at "cracking" and "yielding." The routine methods overestimate significantly the observed initial stiffness and underestimate yield deformation. A wide scatter is reported in the observed cracking moment. Yield and ultimate resistance can be conservatively estimated by the routine procedure.