Abstract: A high load extendible structure including an elongated thin pre-stressed element which has a cross section whose interior portion is curved to form substantially one-half of the perimeter of a circle and whose two exterior portions are each curved in an opposite direction to each form substantially one-quarter of a circle of the same radius as the central portion when the pre-stressed element is unrestrained from a flattened condition. The element is capable of being rolled flat upon a roller and yet can be extended to support or push various loads and plastic beads are located along the edges of the pre-stressed element to provide protection from these sharp edges. An equation is presented for determining the required thickness of the element once the radii associated with the element and the radius of the roller and other parameters for a given application have been determined.