Bearing bar sizes and pitch, cross bar pitch, surface treatment options and load selection logic for welded, press-locked, serrated grating and stair treads. Compiled from ANSI/NAAMM MBG 531, BS 4592 and EN ISO 14122 walkway guidance.
A steel grating panel is defined by two parameters above all others: the bearing bar (the load-carrying bars running in the span direction) and the pitch (spacing of those bars and of the cross bars). Almost every performance question — load capacity, open area, slip resistance, weight — traces back to these choices.
We manufacture to two base material families. Carbon steel (ASTM A36 / Q235B) is the standard for the majority of industrial platforms, walkways and trench covers, finished with hot-dip galvanizing for corrosion protection. Stainless steel (304 / 316) is specified where the environment is wet, acidic, saline or food-contact, with 316/316L the upgrade for chloride exposure such as coastal or chemical plants.
For most structural floors, welded steel grating with 30 mm or 40 mm bearing bar pitch is the workhorse specification. When the top surface must be flat and weld-free — architectural decks, pedestrian bridges, façade screens — press-locked grating is the right choice. Where floors are wet or oily, serrated bearing bars add the grip that plain bars cannot.
Once you have the grade, bar size and pitch, see the steel grating product page for our standard supply envelope, MOQ and lead times.
Each manufacturing method delivers a different balance of strength, surface finish and cost. Selection depends on whether the deck is structural, architectural or slip-critical.
Bearing bars and cross bars are joined by resistance welding at every intersection. This is the most common general-purpose grating for industrial floors.
Cross bars are pressed into pre-notched bearing bars and locked under pressure, leaving a smooth, flat top surface with no visible welds.
Teeth are formed along the top edge of each bearing bar, providing high slip resistance on wet, oily or inclined surfaces.
Prefabricated grating panels with a nosing and pre-welded end plates for direct fixing to stringers, supplied as a finished safety component.
| Type | Top surface | Strength | Typical application |
|---|---|---|---|
| Welded | Flat, welded | Very high | Industrial platforms, walkways |
| Press-locked | Smooth, weld-free | High | Architecture, pedestrian bridges |
| Serrated | Toothed (anti-slip) | High | Wet/oily stairs, ramps |
| Stair treads | Nosed panel | High | Plant access stairs |
Standard combinations used in our steel grating production. Custom bar sizes, pitches and panel dimensions are available on request.
| Parameter | Standard range / options | Notes |
|---|---|---|
| Bearing bar height | 20 – 100 mm | Taller bar = higher load capacity at given span |
| Bearing bar thickness | 2 – 10 mm | 3 mm and 5 mm most common |
| Bearing bar pitch | 30, 33, 40, 60 mm | 30 / 40 mm are the industrial standard |
| Cross bar pitch | 50, 100 mm | 100 mm standard; 50 mm for higher stiffness |
| Panel width | up to 1000 mm | Cut to project module |
| Panel length | up to 6000 mm | Custom length per support layout |
| Surface treatment | Hot-Dip Galvanized / Painted / Untreated | HDG to EN ISO 1461 for outdoor use |
| Load class | Designed per span & support | Confirm with drawing or load table |
| Standards | ANSI/NAAMM MBG 531, BS 4592 | Third-party inspection on request |
Open area typically falls between 60% (30 mm pitch, 5 mm bar) and 80% (60 mm pitch, thin bar). Higher open area improves drainage and light passage but reduces load capacity — balance against the application.
Steel grating is not rated by a single "load class". The safe allowable load depends on the bar section, the support span and how the panel is fixed.
Use this decision tree to narrow down the right specification for your project.
Structural plant floor or trench cover → Welded grating, 30/40 mm pitch, carbon steel + HDG. Pedestrian bridge or façade → Press-locked for a clean surface. Wet or oily stair → Serrated with nosing. Food or marine → Stainless 304/316.
Pitch is set by the required open area and load. Bar height and thickness are then chosen against the support span. For most walkways, 40×5 mm at 30 mm pitch is a sound starting point; heavier plant decks move to 50–60 mm bars.
Outdoor or industrial → Hot-dip galvanizing (EN ISO 1461). Indoor dry → Painted or untreated. Corrosive/wash-down → Stainless base material rather than coating.
Provide panel dimensions, required cutouts (pipes, columns), banded edges, toe plates and fixing method. For stairs, give going width and stringer spacing so we can supply ready-to-fit treads.
Zhaobang Metal manufactures and inspects to the following internationally recognized standards. Links open the issuing organization's official page.
Welded steel grating uses resistance welding at every bearing bar and cross bar intersection, giving high shear strength and the lowest cost for most industrial loads. Press-locked (swage-locked) grating presses the cross bars into pre-cut notches in the bearing bars, producing a smooth, flat top surface with no visible welds — preferred for architectural and pedestrian-facing applications where appearance matters.
For heavy plant platforms and vehicular trench covers, 50×5 mm or 60×5 mm bearing bars at 30 mm or 40 mm pitch are common starting points. Load capacity is governed by the bar height-to-span ratio: a taller, thicker bar or a shorter support span both increase allowable load. Send us your span and load requirement and we will confirm the specification.
Our hot-dip galvanizing follows EN ISO 1461 (equivalent to ASTM A123). It specifies minimum zinc coating thickness by steel thickness — typically 70–85 µm on grating sections — plus coating adhesion and appearance requirements, delivering long-term corrosion protection for outdoor and industrial environments.
Yes. Stair treads are supplied as prefabricated panels with a serrated or checker-plate nosing for slip resistance, pre-welded end plates (with or without bolt holes) for direct fixing, and optional yellow warning nosing. They are cut to the required going width and stringer spacing.
Yes. As a direct manufacturer we produce panels to your exact dimensions, including circular or rectangular cutouts for pipes and columns, banded edges, toe plates and tagged marking. Send the drawings or marked-up sketch and we will quote against it.