The document discusses different types of bridges and structures. It defines arch bridges as bridges supported by an arch or series of arches. Suspension bridges have roadways hung from cables between tall towers. Truss bridges are supported by trusses to carry heavy loads without collapsing. Beam bridges are the most common type of bridge, supported by one or more beams. Solid structures rely on their own mass to resist forces, while frame structures gain strength from joined components forming triangles. Shell structures have a solid outer surface and hollow inner area.