Most previous experimental investigations of two-dimensional (2D) granular column collapses have been conducted using three-dimensional (3D) granular materials in narrow horizontal channels (i.e., quasi-2D condition). Our recent research on 2D granular column collapses by using 2D granular materials (i.e., aluminum rods) has revealed results that differ markedly from those reported in the literature. We assume a 2D column with an initial height of h(0) and initial width of d(0), a defined as their ratio (a = h(0)/d(0)), a final height of h(infinity), and maximum run-out distance of d(infinity). The experimental data suggest that for the low a regime (a <= 0.65) the ratio of the final height to initial height is 1. However, for the high a regime (a >= 0.65), the ratio of a to (d(infinity) - d(0))/d(0), h(0)/h(infinity), or d(infinity)/d(0) is expressed by power-law relations. In particular, the following power-function ratios (h(0)/h(infinity) approximate to 1.42a(2/3) and d(infinity)/d(0) similar to 4.30a(0.72)) are proposed for every a >= 0.65. In contrast, the ratio (d(infinity) - d(0))/d(0) approximate to 3.25a(0.96) only holds for 0.65 <= a <= 1.5, whereas the ratio (d(infinity) - d(0))/d(0) approximate to 3.80a(0.73) holds for a >= 1.5. In addition, the influence of ground contact surfaces (hard or soft beds) on the final run-out distance and destruction zone of the granular column under true 2D conditions is investigated.