truss-beam

Century Dictionary and Cyclopedia

1. n. A wooden beam reinforced by a tie-rod, or a compound wooden beam composed of two or more wooden members and reinforced by means of a tie-rod, or a built-up beam of iron arranged in the form of truss. The most simple form is a single piece of timber having an iron tie-rod on the under side secured at each end of the beam, serving to resist the strain of tension on the under side of the beam when carrying a load. The lower beams of a railroad passenger-car are a good example. Another and less common form is a wooden beam having cast-iron struts to resist the strain of compression. Several beams united and reinforced by a tie-rod may form a compound truss-beam. Iron truss-beams have usually only tie-rods of wrought-iron, with sometimes box-beams for the upper chord. Truss-beams are used in car-building, in roofs of all kinds, and for short bridges. See beam, truss, and bridge.