The document discusses different types of bridge structures and their characteristics. It also defines key structural engineering terms. 1. Arch bridges distribute weight across supports on both sides through an arched structure. Beam bridges have two supports at each end, while truss bridges use triangular frames to provide strength while remaining lightweight. 2. Suspension bridges hang from cables anchored into towers and concrete supports. Solid structures are made from one solid piece of strong material, while frame structures use rigidly connected parts. Shell structures have a solid outer surface that can be rounded or flat. 3. The document defines structural engineering terms like shear, tension, and compression - describing the directional forces they apply to objects.