Portal-frame warehouses, multi-storey frames, transmission towers and plant structures all depend on bolted connections. Structural bolting is a discipline of its own: the bolt must achieve a defined preload, keep it under vibration and thermal cycling, and be inspectable decades later. That is why we supply structural bolts to recognised standards rather than generic hardware.
Structural Bolting with DIN933
DIN933 fully-threaded hex bolts, paired with nuts and washers to matching property classes (typically 8.8 and 10.9), are the workhorse of steel-to-steel connections: beam-to-column splices, base plates, bracing and purlin cleats. Fully threaded shanks simplify detailing where grip lengths vary, and the property-class marking on the head makes every connection traceable to its strength grade.
Pre-Installation & Torque Control
- Assemble with clean, undamaged threads; wire-brush re-used galvanised threads and re-lubricate them to keep the torque-tension relationship predictable.
- Tighten in stages - 30%, 70%, 100% of specified torque - working from the stiffest part of the joint (usually the centre of a bolt group) outwards.
- Use hardened washers under both head and nut to protect the connected ply and prevent rotation galling.
- On slip-critical connections, follow the specified surface class; paint or overspray on faying surfaces destroys slip resistance.
Typical Applications
- Portal-frame warehouse and factory structures
- Beam splices, base plates and haunch connections
- Bracing systems, towers and masts
- Secondary steel: purlins, rails, bracing rods and sag rods
- Plant and conveyor gantry structures
Surface Protection & Corrosion
Hot-dip galvanised or zinc-flake coated bolts suit most external and humid environments; for immersion, coastal or chemical exposure we supply Duplex systems (galvanised plus painted) and stainless structural fasteners. Remember that the coating of the bolt must be compatible with the coating of the steel it touches - mixed metallic coatings can set up galvanic cells at the connection.
Why Choose BuildFastener
Our structural bolts come with batch-traceable property-class certification, consistent head markings and thread tolerances that match standard nuts without cross-threading - the details that keep site erection on schedule and inspection painless.
Need fasteners for your project?
Consultar
