Trusses are structural frames used in construction to provide support for roofs, walls, and other structures. They are composed of BEAMS and ties, which are connected together in a triangular pattern. BEAMS are long, straight pieces of wood or metal that form the main support structure of a truss, while ties are shorter pieces of wood or metal that connect the BEAMS together. Trusses are often used in bridges, buildings, and other large structures, as they provide a strong and stable support system.