Figure 7-2. - American standard reinforcing bar marks.

lines and then pulled out or expanded to form a diamond shape between each parallel cut. Another type is square, rather than diamond shaped, as shown in view B, figure 7-3. Expanded metal is customarily y used during plastering operations and light reinforcing concrete construction, such as sidewalks and small

Figure 7-3. - Expanded or diamond mesh steel reinforcement.

concrete pads that do not have to bear substantial weight, such as transformer and air-conditioner pads.

Welded Wire Fabric

Welded wire fabric is fabricated from a series of wires arranged at right angles to each other and electrically welded at all intersections. Welded wire fabric, referred to as WWF within the NCF. has various uses in reinforced concrete construction. In building construction, it is most often used for floor slabs on well-compacted ground. Heavier fabric, supplied mainly in flat sheets, is often used in walls and for the primary reinforcement in structural floor slabs. Additional examples of its use include road and runway pavements, box culverts, and small canal linings.

Four numbers are use-d to designate the style of wire mesh; for example, 6 by 6-8 by 8 (sometimes written 6 x 6 x 8 x 8 or 6 x 6 - W 2.1 x W 2.1). The first number (in this case, 6) indicates the lengthwise spacing of the wire in inches; the second number (in this case, 6) indicates the crosswise spacing of the wire in inches; the last two numbers (8 by 8) indicate the size of the wire on the Washburn and Moen gauge. More recently the last two numbers are a W number that indicates the size of the cross-sectional area in the wire in hundredths of an inch. (See table 7-4.) WWF is currently available within the Navy stock system using the four-digit system, 6 by 6-8 by 8, as of this writing, but if procured through civilian sources, the W system is used.