Concrete Reinforcing Mesh Calculator
About Concrete Reinforcing Mesh Calculation
This concrete reinforcing mesh calculator determines the number of longitudinal and transverse reinforcement rods, their total length, and theoretical weight. It also calculates the distances from the outermost rods to the mesh edges, the weight of one mesh sheet, the number of sheets required for a specified area, and their total weight.
The calculation is based on the mesh dimensions, rod spacing, and reinforcement diameters. A steel density of 7850 kg/m3 is used for the weight calculation. No additional safety factors are applied to the calculated weight or number of mesh sheets.
Guidelines and recommendations
Rod directions and spacing
Longitudinal rods. Rods with diameter D1 run along the mesh length L. The distance between them is measured across the mesh width B and is defined as the transverse pitch S1.
Transverse rods. Rods with diameter D2 run across the mesh length. The distance between them is measured along dimension L and is defined as the longitudinal pitch S2.
Number of reinforcement rods
Longitudinal direction. The number of longitudinal rods is calculated from the mesh width B and transverse pitch S1. Dimensions are entered in millimeters.
N1=⌊B/S1⌋+1
Transverse direction. The number of transverse rods is calculated from the mesh length L and longitudinal pitch S2.
N2=⌊L/S2⌋+1
The symbol ⌊ ⌋ means that the division result is rounded down to the nearest whole number. One additional rod is then added to obtain the required number of reinforcement lines across the specified dimension.
Distances from the outer rods to the edges
Symmetrical arrangement. If the mesh width or length is not exactly divisible by the corresponding pitch, the calculator keeps the specified spacing between rods. The remaining dimension is divided equally between the two opposite edges.
A1=(B mod S1)/2
A2=(L mod S2)/2
Here, A1 is the distance from the mesh edge to the nearest longitudinal rod, while A2 is the distance from the edge to the nearest transverse rod. If the dimension is exactly divisible by the pitch, the corresponding distance is 0 mm.
Total reinforcement length
Longitudinal rods. Each longitudinal rod has a length equal to L. The total length is calculated by multiplying the mesh length by the number of longitudinal rods and converting millimeters to meters.
L1,tot=N1·L/1000
Transverse rods. Each transverse rod has a length equal to B.
L2,tot=N2·B/1000
Reinforcing mesh weight calculation
Theoretical weight. For each direction, the calculator first uses the circular cross-sectional area of the reinforcement rod and then multiplies it by the total rod length and the steel density ρ=7850 kg/m3. The diameter is entered in millimeters, so the cross-sectional area is converted from mm2 to m2.
M1=7850·π·D12·L1,tot/(4·106)
M2=7850·π·D22·L2,tot/(4·106)
Weight of one mesh sheet. The weights of the rods in both directions are added together.
Mmesh=M1+M2
This method gives the theoretical reinforcing mesh weight based on the nominal rod diameter and steel density. Each direction is calculated separately, so diameters D1 and D2 may be different.
Number of mesh sheets and total weight
Area of one mesh sheet. With width B and length L entered in millimeters, the area of one sheet in square meters is calculated using the conversion factor 106.
Amesh=B·L/106
Number of sheets. The specified coverage area A in m2 is divided by the area of one mesh sheet. The result is always rounded up to the next whole sheet.
n=⌈A/Amesh⌉
The symbol ⌈ ⌉ means rounding up. For example, a calculated value of 9.1 gives a final result of 10 mesh sheets.
Total weight of all mesh sheets. The weight of one sheet is multiplied by the calculated number of sheets.
Mtotal=Mmesh·n
The number of mesh sheets is calculated from their net geometric area. Overlaps, cut-offs, and installation allowance do not automatically increase the calculated quantity.
Result rounding
Length and weight. The total reinforcement length is displayed rounded to the nearest whole meter. The weight for each direction, the weight of one mesh sheet, and the total weight of all sheets are displayed to 0.01 kg.
The weight calculation uses the original unrounded total rod length. For this reason, the calculated weight is more precise than a manual recalculation based only on the rounded length shown in the results.
Relation to European standards
EN 1992-1-1, Eurocode 2: Design of concrete structures. General rules and rules for buildings. This standard is used when specifying reinforcement parameters for reinforced concrete elements, including reinforcement arrangement, spacing, and detailing requirements.
EN 10080, Steel for the reinforcement of concrete. Weldable reinforcing steel. General. This standard specifies general requirements for weldable reinforcing steel and factory-produced welded reinforcing mesh. The calculator uses the diameters and spacing entered by the user for its geometric calculation and determines weight from the nominal rod geometry and steel density.
FAQs
Why does transverse pitch S1 apply to longitudinal rods?
Longitudinal rods run along the length L, but the distance between adjacent longitudinal rods is measured across the mesh. Therefore, S1 is the transverse pitch and is used together with width B to determine the number of longitudinal reinforcement rods.
Why does the calculator keep the spacing unchanged when the mesh dimension is not exactly divisible by it?
The specified pitch is preserved between adjacent reinforcement rods. The remaining dimension after division by the pitch is split equally between the two edges, producing a symmetrical mesh layout.
Why can the reinforcing mesh weight differ from a calculation based on the displayed total length?
The total reinforcement length shown in the results is rounded to the nearest whole meter, while the weight is calculated using the original unrounded length. A manual weight calculation based only on the displayed length can therefore produce a slightly different result.
How is the number of mesh sheets calculated when the coverage area is not exactly divisible?
The required coverage area is divided by the area of one mesh sheet, and the result is rounded up. Even a small remaining area therefore increases the result by one additional sheet.
Why can the actual weight of concrete reinforcing mesh differ from the calculated weight?
The calculator uses nominal reinforcement rod diameters and a steel density of 7850 kg/m3. The actual weight of manufactured reinforcing mesh may vary slightly because of dimensional tolerances and the surface profile of the reinforcing steel.