Softwoods are classified according to extent of manufacture as: Rough Lumber. Lumber that has not been dressed (surfaced) but has been sawed, edged, and trimmed. Dressed (Surfaced) Lumber. Lumber that has been dressed by a planning machine (for the purpose of attaining smoothness of surface and uniformity of size) on one side (S1S), two sides (S2S), one edge (S1E), two edges (S2E), or a combination of sides and edges (S1S1E, S1S2, S2S1E, S4S). Worked Lumber. Lumber that, in addition to being dressed, has been matched, shiplapped or patterned: Matched Lumber. Lumber that has been worked with a tongue on one edge of each piece and a groove on the opposite edge. Shiplapped Lumber. Lumber that has been worked or rabbeted on both edges, to permit formation of a close-lapped joint. Patterned Lumber. Lumber that is shaped to a pattern or to a molded form. Softwoods are also classified according to nominal size: Boards. Lumber less than 2 in in nominal thickness and 2 in or more in nominal width. Boards less than 6 in in nominal width may be classified as strips. Dimension. Lumber from 2 in to, but not including, 5 in in nominal thickness, and 2 in or more in nominal width. Dimension may be classified as framing, joists, planks, rafters, studs, small timbers, etc. Timbers. Lumber 5 in or more nominally in least dimension. Timber may be classified as beams, stringers, posts, caps, sills, girders, purlins, etc. Actual sizes of lumber are less than the nominal sizes, because of shrinkage and dressing. In general, dimensions of dry boards, dimension lumber, and timber less than 2 in wide or thick are 1/4 in less than nominal; from 2 to 7 in wide or thick, 1/2 in less, and above 6 in wide or thick, 3/4 in less. Green-lumber less than 2 in wide or thick is 1/32 in more than dry; from 2 to 4 in wide or thick, 1/16 in more, 5 and 6 in wide or thick, 1/8 in more, and 8 in or above in width and thickness, 1/4 in more than dry lumber. There are exceptions, however. Yard lumber is classified on the basis of quality as: Appearance. Lumber is good appearance and finishing qualities, often called

Vanadium stains are not powdery crystalline deposits and cannot be simply brushed off. They are often mistaken for moss or algae, which usually grows in damp areas across the whole face of the bricks and mortar. By contrast vanadium stains (as shown below) appear on dry walls, normally as patches on the brick only. Vanadium is a metallic salt present in most light coloured clays throughout the world. It is present in very small quantities. Figure 7 Vanadium staining on brick face Vanadium salts are put into solution by excess water migrating through the bricks and are brought to the surface as the bricks dry out. As the water evaporates from the drying bricks the vanadium salts are left on the brick surface. The vanadium salt turns green when it crystallises in an acidic environment, such as after acid cleaning or upon exposure to rainwater (naturally acidic). Vanadium salts are colourless until they are exposed to an acidic environment. This process can occur whenever the bricks are subjected to excessive water from rain either before or (more often) during the bricklaying process. If vanadium stains are not removed prior to cleaning with hydrochloric acid (for the removal of mortar stains), they may turn a darker colour and be more difficult to remove.

FIGURE 5.21 Shear and moment diagrams for a simply supported, uniformly loaded beam. Shear diagrams for commonly encountered loading conditions are given in Figs. 5.30 to 5.41. 5.5.5 Bending-Moment Diagrams The unbalanced moment of the external forces about a vertical section through a beam is called the bending moment. It is equal to the algebraic sum of the moments about the section of the external forces that lie on one side of the section. Clockwise moments are considered positive, counterclockwise moments negative, when the forces considered lie on the left of the section. Thus, when the bending moment is positive, the bottom of the beam is in tension. A diagram in which the bending moment at every point along the length of a beam is plotted as an ordinate is called a bending-moment diagram. Figure 5.20c is the bending-moment diagram for the beam loaded with concentrated loads only in Fig. 5.20a. The bending moment at the supports for this simply supported beam obviously is zero. Between the supports and the first load, the bending moment is proportional to the distance from the support, since it is equal to the reaction times the distance from the support. Hence the bending-moment diagram for this portion of the beam is a sloping straight line. The bending moment under the 6000-lb load in Fig. 5.20a considering only the force to the left is 7000
10, or 70,000 ft-lb. The bending-moment diagram, then, between the left support and the first concentrated load is a straight line rising from zero at the left end of the beam to 70,000 ft-lb, plotted to a convenient scale, under