# Reinforcing mesh

Hot-dip galvanized welded wire mesh
interposed welded wire mesh
A construction worker applies shotcrete to welded wire mesh

Welded steel mesh , steel mats or grids are wire mesh of welded rods made of reinforcing steel , which for reinforcement (reinforcement) of sheet-like reinforced concrete construction parts , such as floor plates are used, ceilings or walls. They are industrially manufactured in quality-monitored manufacturing plants on semi-automatic or fully automatic machines and consist of crossing longitudinal and cross bars of hot or cold-formed, ribbed reinforcing steel , which are shear-resistant at the crossing points by resistance spot weldingare connected. Depending on the application conditions, they are used with and without additional corrosion protection.

In common parlance, welded wire mesh is also referred to as reinforcement mesh or reinforcement mesh. In a lighter version for use in plaster and mortar , they are also available as screed grids , screed mats , reinforcement grids or mesh reinforcement .

## List of types of welded wire mesh

• List and drawing mats that are produced according to the customer's specifications
• Storage mats are expanded, standardized welded wire meshes in different variants with a single-level joint compared to storage mats
• Ironing mats for the production of three-dimensional reinforcement cages
• Road mats for the reinforcement of concrete roads or large concrete surfaces, such as runways
• Special dyn mats for components with increased dynamic stress
• N-mats no longer conform to DIN 488 standards, which is why they must not be used for statically stressed components

All types of mats - with the exception of N mats, i.e. Q and R mats - are generally suitable for dynamic (i.e. not predominantly static) loads .

Reinforcing wire mesh must be labeled with regard to its origin in two ways. On the one hand, the raw material must be provided with a rolling mark that is rolled onto the reinforcing steel B500A or B500B (formerly BSt 500 M), and on the other hand, a weather-resistant label must be attached to the mat itself, which shows the manufacturer in which this mat was made was welded.

Reinforced steel mats are standardized in DIN 488-4. According to the definitions of the DIN standard , welded wire mesh are made of ribbed bars with a nominal diameter of 6 to 14 mm and are classified as normal or highly ductile according to DIN 1045-1, Table 11, depending on the raw material used. For the nominal diameter of 14 mm, only highly ductile pre-material B500B may be used.

Highly ribbed starting material B500A and B500B as well as deeply ribbed starting material B500A may be used for the production of welded wire mesh.

According to DIN 488-4: 2009-08 and DIN 1045-1, welded wire mesh with wire diameters <6 mm may no longer be used for static purposes and for dimensioning according to DIN 1045-1.

The name for mats is welded wire mesh B500A or B500B (formerly BSt 500 M).

## Storage mats

Storage mats are mats that have specified dimensions. This applies to the external dimensions as well as rod spacing and cross-sections. They can be supplied directly from stock by various manufacturers.

There are essentially three types of storage mats type Q, type R, and type N. Some manufacturers also supply other types than storage mats.

The Q-mats have the same steel cross-section per meter of length (cm² / m) in both directions and mostly a square bar spacing of 150 × 150 mm (exception Q 636 with 100 × 125 mm). They are usually used when there is a load in both directions. The mesh designation (e.g. Q 335 A / B) indicates 100 times the steel cross-section in both directions (the Q 636 deviates slightly). The following Q-mats are currently popular: Q 188 A / B, Q257 A / B, Q 335 A / B, Q424 A / B, Q 524 A / B, Q 636 A / B.

The R-mats have different steel cross-sections per meter of length in both directions, it is 20% of the cross-section of the main direction in the transverse direction. The bar spacing is different 150 × 250 mm. They are usually used in one direction when the load is high. The mesh designation (e.g. R 335 A / B) indicates 100 times the steel cross-section in the main direction. The following R mats are currently popular: R 188 A / B, R 257 A / B, R 335 A / B, R424 A / B, R 524 A / B.

The Q and R mats have the external dimensions of 6.00 × 2.30 m (Q 636 A / B is 6.00 × 2.35 m). They are made from reinforcing steel according to DIN 488. They can be ordered with normal ductility (additional designation A) or highly ductile (additional designation B).

In addition, some manufacturers still have the N-mats, but they play a subordinate role. N-mats are so-called non-static mats that are made from normal round steel, i.e. no reinforcing steel according to DIN 488. They must not be used for statically stressed components. There are mats N 94 and N 141.

## List mats

List meshes are meshes that have no specified dimensions. They are usually made to order. Tables are created according to defined designations, which specify the external dimensions, bar diameter, bar spacing and the end bar protrusions. The weldability of the rod diameters in both directions must always be ensured.

## Drawing mats

Drawing meshes are meshes for which a drawing is created. They are made to order. In the drawings the shape, the external dimensions, the bar diameter, the bar spacing and the end bar overhangs are indicated. These mats can have almost any shape. However, here too, the weldability of the bars must be ensured.

## Mechanical values ​​prescribed by DIN 488

• Yield strength 500 N / mm²${\ displaystyle R_ {e}}$
• Tensile strength 550 N / mm²${\ displaystyle R_ {m}}$
• Yield strength ratio with normal ductility 1.05, with high ductility 1.08${\ displaystyle R_ {m} / R_ {e}}$
• Total elongation at maximum load with normal ductility min. 2.5%, with high ductility min. 5%${\ displaystyle A_ {gt}}$