bar grating — open steel grating

Calculator welded grating

There are three pieces of steel gratings placed on the floor.

The weight calculation for the steel grating means its theoretical weight.

The weight of the steel grating is the theoretical weight after the wrapping and the surface treatment. The end edge, opening and the cut out are different so the real weight maybe not as the same as the theoretical weight. The calculating basis is the theoretical weight on the steel grating platform weight calculation and the steel grating delivery settlement. When the length of the steel grating is less than 1 m or there is end edge for the steel grating, the weight would increase. When we wrap with the bearing bar and the length of the steel grating is more than 1 m, we use the following computational formula to calculate the theoretical weight.

Wt = (b1t1N1 b2t2N2 2b3t3)ρμ × 10-6

For this computational formula

  • Wt: the steel grating weight and the unit is kilogram per square meter (kg/m2);
  • t1: the bearing bar width and the unit is millimeter (mm);
  • b1: the bearing thickness and the unit is millimeter (mm);
  • N1: the bearing bar number for the steel grating;
  • t2: the cross bar width and the unit is millimeter (mm);
  • b2: the cross bar thickness and the unit is millimeter (mm);
  • N2: the cross bar number for the steel grating;
  • t3: the width of the bearing bar with the end bar and the unit is millimeter (mm);
  • b3: the bearing bar thickness with the end bar and the unit is millimeter (mm);
  • ρ: the material density and the unit is kilogram per cubic meter (kg/m3) and the steel material density is 7850 kg/m3;
  • μ: the surface treatment weight gain coefficient and for the hot dipped galvanized coating is 1.06.

Inquiry for Our Product

When you contact us, please provide your detail requirements. That will help us give you a valid quotation.

  • Description:
  • 1. Select the type of calculation
  • 2. Complete the fields marked in blue
  • 3. The calculated values are displayed in the boxes marked with green color
  • 4. The values without color do not take into the calculation of a given type
  • 5. Click «Calculate»


  • Note:
  • 1. The calculated values are calculated based on the relationship of theoretical and determine the strength of the grating as indicative.
  • 2. Concentrated loads and continous loads are allowable loads taking into account the maximum possible deflection of the grating.
  • 3. Depending on the mesh size or dimensions of flat, load values are calculated from the condition of load capacity or condition of use.
  • 4. The values of the dimensions of flat and mesh size should be correlated with the program production of company Kraty Mostostal Kraków.

Welded bar grating provides
one piece grating with a flush top surface.  It is widely used for
walkways, fire escapes, and decks where a non-slip surface is desired. 
We will cut any stock grating to your exact sizes or can order special sized


following table indicates the maximum unsupported span to safely support
pedestrian traffic.  Loads are based on 19-W-4 steel bar grating and
19-P-4 aluminum bar grating.


Steel Grating

Aluminum Grating








1/8 x 34

3/16 x 3/4

1/8 x 1

3/16 x 1

1/8 x 1 1/4

3/16 x 1 1/4

1/8 x 1 1/2

1/8 x 1

3/16 x 1

3/16 x 1 1/4

1/8 x 1 1/2

3/16 x 1 3/4

3/16 x 1 3/4

3/16 x 2


Metalworld stocks aluminum grating in a 3/16″
x 1″ rectangular bar type grating.  Other sizes of aluminum grating are
available on special order.

Conversion Factors:

For gratings with other than 1-3/16’’ bearing or spacing or for different design stresses, proportionate conversion factors apply. For information on other types of grating consult the manufacturer.


This bar grating calculator is intended for informational purposes only for pedestrian traffic. It has been developed using load table information supplied by the National Association of Architectural Metal Manufacturers for steel welded bar grating type 19W4/19W2.

This information is of a technical nature, and as such is intended only for evaluation by technically skilled persons, with any use thereof to be at their independent discretion and risk. Such information is reliable when evaluated in the proper manner by licensed engineering personnel.


* Approximate weight Lbs./Sq. Ft. Weight depends on panel width, cross bar selection, mill tolerance, and manufacturing tolerance.
** Recommended maximum span for 1/4’’ deflection under concentrated load at 300# at midspan on 6’ or less. 400# over 6’.
*** Deflection in inches.

¹ Uniform Concentrated Load Lb/Sq. Ft.
² Safe Concentrated Load Lb/Sq. Ft. of grating width, at mid-span.

1/4’’ is recommended as the maximum deflection consistent with pedestrian comfort but can be exceeded for other loading conditions at the discretion of the engineer.

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