An elongate structure for supporting heavy loads includes an elongate hollow cylinder having a longitudinal axis of symmetry. Stress-distributing strengthening members are circumferentially positioned about and secured to the hollow cylinder in parallel relation to the longitudinal axis of symmetry. A first flat plate is disposed in overlying relation to the hollow cylinder and to the first, upper pair of strengthening members and a second flat plate is disposed in underlying relation to the hollow cylinder and to the second, lower pair of strengthening members. The second flat plate is disposed in a horizontal plane in parallel and diametrically opposed relation to the first flat plate. A key extends from a first end of the hollow cylinder and a mating socket is formed in a second end of the hollow cylinder to facilitate end-to-end interconnection of a plurality of the hollow cylinders.