Abstract: A structural element is disclosed which is substantially composed of a linked chain and of a flexible connection which can be a chain of identical links and which can be assembled together as required to form a rigid beam. The linked chain comprises opposing support points, the first support point of one link of row n of the chain cooperating with the second support point of a link of row n-1 to contain, while the element is being rendered rigid, hooking elements integral with the flexible connection and which, in the preferred embodiment of the invention, are the pins of the second chain. The structural element can be assembled or disassembled using a special device.