In this reading Ching covers a plethora of Material spans and their characteristics, He lists things like Masonry arches, Wood beams and joists, subflooring, planks, beams, decking and reinforced concrete. Masonry arches fall into different categories like Segmental arches, gothic arches, Lancet arches, drop arches and roman arches, these arches have different radii points and are pointed or semi-circle, also there are basket and jack arches. Wood beams are essential subsystems and are quick at assembly and very efficient, they can form a level working platform for construction they must be taken care of, so they do not rot. Spans range from 10’ to 18’ depending on 2x(x) ex. 2×4 or 2×6, Wood beams come un different types like Built up, boxed, flitch and spaced beams. Wood subfloor goes under joists and can be used as a platform during construction. The subflooring typically consists of plywood, the under layment provides impact load resistance and a smooth surface for nonstructural flooring, Wood decking comes un different thickness 2×6 and 2×8 and 3×6, 4×6 and can come in a laminated version and comes in simple double and continuous span. Steel cones in different shapes from I, W, C AND Structural steel. Connections can be made by tons of way sake riveting or welding, Open web steel joist are light and can have cabling going through them, decking serves as tensile reinforcement for concrete slabs. Reinforced concrete beams are designed to act together within longitudinal and web reinforcement.