Terminology
 

Area of Steel – The cross-sectional area of steel, measured in square inches (in²).

Building Mesh – A series of longitudinal and transverse wires arranged at right angles to each other and welded together at their points of intersection. Material is produced in standardized sheets and rolls. Typical wire sizes range from 10 gauge, to 4 gauge in four common sheet sizes: 5’x10’, 8’x12’-6”, 8’x15’, and 8’ x 20’. Rolls are generally produced in five foot widths with varying lengths from 100’ to 750’.

Cross Wire – The cross wire is at right angles to the line wires and welded together at points of intersection. Typically the cross wire is also known as the transverse wire.

Deformed Wire – The wire surface will have raised or indented deformation similar to those on conventional rebar.

Development Length – The length of reinforcement or anchorage to transfer stresses from the steel wire (or steel bar) into the surrounding concrete.

End Overhangs - Extension of longitudinal wires beyond centerline of first and last traverse wires (end overhangs are included in the sheet length dimension).

Finger Lap – The lapping of two sheets by lapping individual wires (side by side) that resemble long overhangs on the edges of the sheet.

Grade of Steel – The strength properties of the steel. For example grade 60 has a yield strength of 60,000 psi.

Lap Length – The lap length is a function of the development length times a 1.3 (deformed wire) or 1.5 (smooth wire) factor.  ACI 318 establishes minimum lap lengths depending on the type of lap and whether the wire is smooth or deformed. The codes permit two types of lap, a finger lap and an overlap. Finger laps are only permitted with deformed wire while overlaps can use both deformed and smooth wires.

Line Wire - The line wire is at right angles to the cross wires and welded together at points of intersection. Typically the line wire is also known as the longitudinal wire.

Longitudinal Wire - The longitudinal wire is at right angles to the transverse wires and welded together at points of intersection. Typically the longitudinal wire is also known as the line wire.

Overall Width - Tip to tip dimension of transverse wires (this dimension is the sheet width plus both side overhangs).

Overlap – The overlapping of two sheets by lapping them one over top of the other.

Sheet Length - Tip to tip dimension of longitudinal wires (the length dimension always includes end overhangs).

Sheet Width - Center to center distance between outside longitudinal wires. This dimension does not include side overhangs.

Side Overhang - Extension of transverse wires beyond centerline of outside longitudinal wires (side overhangs are not included in the sheet width dimension).

Smooth Wire - The wire surface will have no raised or indented deformation.

Splice Length – See lap length.

Strain – The ratio of the change in elongation or stretch over the original length due to an applied load.

Stress – The measure of the average amount of force exerted per unit area.

Structural Mesh – See Welded Wire Reinforcement or Welded Wire Fabric.

Temperature Reinforcement – Reinforcement designed to carry stresses resulting from temperature changes; also the minimum reinforcement for concrete areas which are not subjected to primary stresses.

Transverse Wire – The transverse wire is at right angles to the longitudinal wires and welded together at points of intersection. Typically the transverse wire is also known as the cross wire.

Welded Wire Reinforcement - Welded Wire Reinforcement (WWR) designates a material composed of cold-worked steel wire, fabricated into sheets by the process of electric resistance welding.

Wire Fabric – This is the previous name given to Welded Wire Reinforcement. Welded Wire Reinforcement historically has been referred to as fabric or mesh implying a light gauge material. Welded Wire Reinforcement is structural material with wire sizes up to ¾” in diameter (a #6 bar).

Wire Size - Individual wire size designations are based on the cross-sectional area of a given wire. The "W" and "D" number represents the cross-sectional area of the wire multiplied by 100. The "W" represents a plain wire and the "D" represents a deformed wire. A D10 wire would indicate a deformed wire of 0.10 square inch.

Wire Spacing - The centerline-to-centerline distance between parallel wires.

Yield Strength – The stress at which steel begins to permanently deform beyond its elastic limit.