Failure Mode of Reinforced Concrete Column Without Hoop Reinforcement

Effect of Various Structural Factors on Shear Strength Degradation after Yielding of RC Members under Cyclic Loads

“…The excessive shear strength degradation is also thought to be induced by an inadequate consideration of crucial structural factors. Therefore, extensive experimental cyclic loading tests on flexure designed RC beams and columns were carried out and the influence of crucial structural factors on the degradation behavior of shear strength were investigated (Kani 1966;Niwa et al 1986;Panagiotakos and Fardis 2001;Ishibashi et al 2001). On the basis of the test results, the prediction equations to determine the displacement ductility capacity were established as the function of the above structural factors (Nakamura et al 1992;Krolicki et al 2011), aiming to achieve a displacement-based seismic design.…”

Mechanism of shear strength degradation of a reinforced concrete column subjected to cyclic loading

“…Although a well‐designed RC member under monotonic loading ordinarily suffers flexural failure and shows good deformation performance, if subjected to cyclic loading, the load‐bearing capacity often decreases within a relatively small displacement ductility after the flexural yield of the tension reinforcing bars and ultimately shear failure occurs (called shear failure after flexural yield in this study). Because the deformation ability of a RC member under cyclic loading is significant in seismic deformation‐based design, many researchers have investigated the influences of several factors such as web reinforcement ratio, tension reinforcement ratio, axial load, and shear span‐to‐depth ratio for the ultimate deformation ductility of RC members by numerical and experimental methods …”

“…Because the deformation ability of a RC member under cyclic loading is significant in seismic deformationbased design, many researchers have investigated the influences of several factors such as web reinforcement ratio, tension reinforcement ratio, axial load, and shear span-to-depth ratio for the ultimate deformation ductility of RC members by numerical and experimental methods. [4][5][6][7][8] As shown in Figure 1, the reason for shear failure after the flexural yield of a RC member has been conceptually explained as that the shear strength degrades gradually with the increase of displacement level and ultimately becomes less than the shear demand corresponding to the flexural strength, which leads to a decrease of loadbearing capacity. Corresponding to this failure mode, the relationship between degraded shear strength and displacement ductility (also called the shear capacity degradation curve) was proposed for the first time by the ATC seismic design guidelines.…”