Investigation of the behaviour of shear-critical reinforced concrete columns

A comparative study of the strength and behaviour of a shear-critical cantilever column specimen based on experimental, analytical and numerical investigations is presented in this paper. The specimen was tested under monotonic lateral load. Its strength was predicted using codal provisions and a strut-and-tie model. Its lateral load versus drift behaviour was analytically predicted using a piecewise linear model based on truss analogy, and numerically simulated using three-dimensional (3D) and one-dimensional (1D) finite element (FE) models. Correlation between the tested, predicted and simulated results is discussed in this paper. The study verifies whether the selected methods of analysis give reasonable estimates of strength and behaviour. It was found that the codal expressions under-estimate the shear strength of a short column failing under diagonal crushing. A strut-and-tie model can predict the strength accurately, provided the strut width and softening of concrete are considered appropriately. The behaviour was accurately predicted by a 3D FE model. The analytical model based on a linear truss analogy and the corresponding 1D FE model could trace the behaviour accurately up to cracking. They provided reasonable estimates of the drift at ultimate. These models are suitable in professional practice for a pushover analysis of a building.