Wind Bracing Bracket

What a wind bracing D bracket does in rod bracing

Rod bracing, also called wind bracing, is the X of steel rods in the roof and walls of steel sheds, workshops and portal frame buildings. Each rod runs on a diagonal between frames, so where it passes through a rafter or column it meets the steel at an angle. A wind bracing D bracket is the seat for it: a half round (D shaped) cast block with a slotted hole. Hobson's data sheet shows the bracket set into a hole cut in the steel member, with the bracing rod through the slot and the washer and nut tightened onto its rounded face.

Hobson makes these brackets in malleable cast iron, zinc plated, as part of its low tensile range, and sizes them by metric thread: M12/M16, M20, M24 and M30. Hobson publishes no load capacity, working load or design rating for them. The rod size, the bracket, the bracing layout and how the rods are tensioned come from the engineering design for the building, or the shed maker's design and instructions for a kit shed. Do not change, substitute or add bracing without that design.

Wind bracing bracket sizes and the hole to cut

Hobson gives the hole to cut in the steel as dimension A by dimension F plus dimension I, where A is the width of the hole and F plus I its length, as labelled on the drawing in Hobson's wind bracing D bracket data sheet (linked on this page, with the bracket's other dimensions). The table shows those three and works out the hole for each size.

How a wind bracing bracket is fitted

The steps below follow Hobson's data sheet and photo. Hole positions, rod size and the tension in the rods come from the design.

1. Check the bracket size against the bracing rod size on the drawings or the shed maker's instructions.
2. Cut the hole in the steel member to Hobson's size, A x (F + I): 18 x 41mm for the M12/M16 bracket, 21 x 46mm for M20, 26 x 66mm for M24 and 33 x 85mm for M30.
3. Seat the bracket in the hole with the bracing rod running through its slot.
4. Fit the washer and nut onto the rounded face of the bracket, as Hobson's photo shows, and tension the rod as the design requires. Hobson gives no tightening torque or tension figure for the bracket.

Zinc plated: where it suits

Hobson's coating guide rates zinc plating (5 micron) as low corrosion resistance and recommends it for indoor and non-corrosive environments. It rates hot dip galvanising (50 micron) as high corrosion resistance, recommended for long term outdoor use. Hobson's corrosion guide for metal connectors (written for timber framing connectors, but a useful yardstick) sets the minimum protection by exposure and zone:

• •Inside a fully enclosed, dry building in a very low or low hazard zone (Hobson's guide puts most of Australia more than 50km from the coast in the low zone): zinc plating is the minimum the guide lists.
• •Enclosed buildings in coastal, industrial or sea spray zones: the guide asks for galvanised Z275 or better, so zinc plating is below its minimum there.
• •Sheltered work (roofed but open sided, such as open sheds, carports and verandahs): galvanised Z275 in very low and low zones; Z275 with a soft seal coating or 304 or 316 stainless in coastal and industrial zones; 304 or 316 stainless in sea spray zones. Zinc plating is below the minimum for sheltered work in every zone.
• •Exposed to the weather: 304 or 316 stainless or hot dip galvanising (304 or 316 stainless only in sea spray zones). We do not list a galvanised or stainless D bracket, so have the designer specify the bracket and its corrosion protection for sheltered, exposed or coastal work.
• •Within 2m of a pool edge: the guide calls for 316 stainless.

Wind bracing brackets in Adelaide

Allmat supplies wind bracing D brackets, threaded rod, nuts and washers to shed builders, steel fabricators and erectors across Adelaide and South Australia. Send us the bracing details from your drawings and we will price the lot.

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