Experimental Investigation of Performance of Externally Collared Reinforced Concrete Short Columns

This paper presents the experimental study of nine pieces of reinforce concrete (RC) and short columns. RC short columns were tested with cyclic loading with displacement control under the influence of constant axial load with load index of 0.2. Three columns within the tested nine columns are reference columns which have the details of the reinforcement given in the modern regulations and six of them are 150mm and 100mm externally collared columns. In addition to the parameter of the collar spacing, the cutoff rate (αs=2-1.5-1) is also considered as a parameter. The data obtained from experimental results have shown that externally collar contributes significantly to increasing the shear resistance of RC short columns and limiting the shear dominant behavior. It has been observed that the effectiveness of the externally collar increases with the decrease of the aspect ratio. The values of externally collared columns are much higher than reference columns with perfect secant stiffness, effective stiffness and energy consumption values.