Frangible Sign Support System Recommended Install Method
Recommended Installation for Aluminium Frangible Poles
Foundations should be excavated to the required depth retaining a minimum diameter of 400mm. Remove all loose debris before pouring concrete.
When setting out and pouring concrete on multi pole sites, install kerb side socket first.
The sleeve must be centralised in the hole and set on a concrete base ensuring the sleeve top is between 50 – 90mm above ground level. Place sleeve with the locking bolts facing the oncoming traffic.
Using only wet concrete, carefully pour around the sleeve up to ground level. It is important to ensure that during the final pour the sleeve remains perpendicular by using a spirit level across the sleeve top with sleeve remaining in the centre of the foundation.
When the kerbside sleeve is in place and the site is level, repeat the process with the remaining sleeves. Be careful to ensure that the top of each remaining sleeve is level and perpendicular with the kerbside sleeve.
When the concrete is hardened, generally 24 hours, the poles are placed in the sleeves and firmly secured using the security bolts and transition wear shoe provided. When all sleeves are installed correctly, and the poles are equal length, the pole top should be level ready to install the sign.
For sloping sites, install sleeves 50 – 90mm above ground. The difference in the sleeve levels should be compensated for when calculating the pole lengths to ensure pole tops are level.
- For adequate foundation strength use concrete of not less than 28mpa.
- To ensure that frangibility works within the requirements of NCHRP-350, all pole sizes 50NB and above must be installed using a matching sleeve. All sleeves must be fully encased using wet premixed concrete.
- Check the correct pole size and number of poles required for each installation by referring to the Signfix wind loading charts on pages 15 – 17. Charts are also available online at www.signfix.com.au.
- Obtain all foundation details from a local engineer before the commencement of any installation.
- To prevent difficulty in removing the security bolt from a damaged or bent pole, position sleeves with the locking device facing oncoming traffic.
- The stainless steel transition shoe must be placed between the pole and locking bolts and tightened evenly between 10 & 12 Nm.
- Use standard galvanised post caps or equivalent to prevent water ingress.
- Restraint device can be fit to poles to improve safety in high volume vehicle/pedestrian areas.
In sandy conditions, a silicon bead should be placed in the sleeve top to prevent the ingress of sand into the sleeve. Sand deposits between the pole and sleeve can wedge the pole and prevent removal.