ABSTRACT
Folders are structures composed of rather thin plates and aimed to cover a big span area without columns (Figure 9.1.1a). A folder is considered to be long if its length, l1, is more than the width, l2, and
l2 w 0.5 l1 (9.1.1)
A folder enables to reduce the quantity of materials (relative to ordinary roofs) and consists of plates and beams. A folder is an effective structure, if it includes such constructive elements as diaphragms, bars or load carrying walls at both edges. These elements prevent thrusting of the folder (Figure 9.1.1b, c) and take the corresponding thrust forces that appear at the edges. The load carrying walls are vertical supports for the folder, which in this case replace diaphragms.
