This section starts with Ching explaining masonry arches and lintels. Masonry Arches use the strength of the brick and stone to span openings. He also explains the different arches, for example, a segment arch is struck from a center below the spring line. He goes into wood beams and joists. Wood joist floors is a essential subsystem of wood light frame construction. It can serve as structural diaphragm to transfer lateral loads. Wood subflooring spans across floor joists and is used as a working platform. Steel beams have different types of connections; framed connection, seated connection, shear connection, and semi-rigid connection.