Experimental and numerical comparison of the behavior of elliptic RCC’s made of NC and HSC, with and without casing and wrapping, under axial load

In this study, the numerical and experimental results of the behaviour of RCC’s with an elliptic cross- section made of NC and HSC enclosed by a GRP casing and a CFRP wrapping were compared. Behaviour refers to the compressive capacity and ductility of columns. The effect of concrete type, casing, wrapping and layers number, were investigated. 12 columns with 200*120 diameter and 600 mm height were made. The columns were divided into two groups from NC and HSC, and each group was divided into two part of three; the first part had a casing and the second without casing. Each part had a column without wrapping, 2nd with one layer, and 3rd column with two layers. Numerical modelling was performed with ABAQUS software and the results were compared with experimental results, which were well matched. The results showed that the wrapping and casing improved the behaviour of the columns. Addition of one layer and two layers of wrapping on average in the experimental method causes an increase of 19.7% and 28.7% in the CC in the 1st group and 11% and 28.7% in the 2nd group and in the numerical method causes an increase of 19.9% and 36.6% in CC in the 1st group and 16.8% and 30.9% in the 2nd group. Averagely, the use of casing increased the capacity in the experimental method by 4.15 times in the 1st group and 3.51 times in the 2nd group; in the numerical method; this increase in the capacity in the 1st group was 4.26 times and in the 2nd group was 3.25 times. Although the casing and the wrapping both create confinement, comparison showed that the casing, due to its greater confinement, has a much greater effect on improving the behaviour of columns, especially columns made of NC.