Abstract:

The experimental strengths of twelve reinforced concrete columns, tested under the effect of constant axial load and cyclic lateral load, and the shear capacities obtained from seven widely accepted shear strength models were evaluated in this study. The shear spans, stirrup diameters, concrete strength, and axial load indexes of the columns were considered as parameters. Three of the shear strength models evaluated were regulation/code models. The other five models were shear strength envelope models that consider the shear strength degradation depending on cyclic loading and increasing ductility demand. The evaluation result showed that models of shear strength envelope are quite successful in both determining strength and simulating shear strength degradation. Regulation models take a conservative approach to design, but it has been observed that strength degradation with cyclic loading should be considered. Columns with a shear span of 1.5 are critical to shear-dominant behavior and regulations should take this into account. A further consideration is required for all models in assessing the effect of axial load index on behavior under cyclic loading.

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