Shear Performance of RC Columns with Wide Hoop Spacing at Mechanical Splices

This paper discusses a feasible application of wide hoop spacing to reinforced concrete (RC) columns using mechanical splices for longitudinal bars to simplify and accelerate practical construction. Twenty-two RC columns with/without wide hoop spacing at mechanical splices were experimentally investigated in terms of the shear performance. First, a series of experiments on the application of the proposed hoop arrangement to shear-critical columns was conducted. The tests indicated that the negative effects of the proposed hoop arrangement on the column shear performance were limited and that the wide hoop spacing reduced the shear strengths by up to 12%. Therefore, two structural indices for evaluating the shear strength of columns with the proposed hoop arrangement were presented and verified based on the experimental results. Consequently, strong agreement was obtained between the experimental shear strengths and the estimations obtained with the proposed shear strength evaluation method. Then, a second series of experiments was performed to apply the proposed evaluation method to practical shear design for ductile columns. Premature shear failure in the ductile columns was successfully prevented, thus verifying the effectiveness of the shear design. Furthermore, the rotation angles at shear failure after flexural yielding could be appropriately estimated for several columns by combining the proposed evaluation method with idealized bending performance.