Concrete
The concrete shall consist of 13mm quartzitic stone, Swartkops River sand and Portland Cement, weigh-batched to produce a mix which has an average compressive strength of 50Mpa at 28 days for 150mm test cubes.
The mix shall be compacted by vibration in steel moulds, to produce dense concrete.
Prestressing Wire
Posts are to be prestressed with four crimped prestressing wires accurately positioned in the four corners of the moulds to give a concrete cover of 20 mm. Major posts shall be prestressed with four 5.0mm dia crimped prestressing wires, and intermediate and stay posts with 4.25mm dia crimped prestressing wire.
The prestressing wire shall comply with B.S. 2691 having a yield stress of approximately 1500MN and Young’s Modulus of approximately 200GPa.
The prestressing wires shall be equally tensioned in the moulds by a force producing an initial stress of not more than 70% of the 0,2% proof stress.
No prestressing wires shall be exposed when the posts are erected in concrete.
Fittings
The stay connectors and bolts shall be of hot dipped galvanised mild steel or as specified.
Spacing of Posts
Major post spacing shall be between 30m to 60m maximum on a straight run and fitted with 1 or 2 stay posts each. Major posts fitted with 2 stay posts shall be erected wherever there is a change of direction in the line of the fence.
Intermediate post spacing shall be 3m to 4m.
Standard footing sizes for posts are as below. All footing sizes are dependent on ground conditions and mesh type.
Bending Moments
The major posts, intermediate posts and stay posts are to resist a minimum bending moment of 2.7kN.m, 1.3kN.m and 1.3kN.m respectively, in any position before initial failure occurs.
(Note: The force required to break a post, so that it does not fully recover, is considerably greater than the above specification.)
Dimensions
| Type | Code | Mass | Nominal Dimensions (mm) | Footing Size (mm) |
|---|---|---|---|---|
| Major | MP180 | 57kg | 1800 long, 115 x 115 cross section | 450W x 450L x 600D |
| Stay | SP180 | 31kg | 1800 long, 80 x 80 cross section | 400W x 500L x 350D |
| Intermediate | IP180 | 31kg | 1800 long, 80 x 80 cross section | 350W x 350L x 600D |
| Type | Code | Mass | Nominal Dimensions (mm) | Footing Size (mm) |
|---|---|---|---|---|
| Major | MP210 | 65kg | 2100 long, 115 x 115 cross section | 450W x 450L x 600D |
| Stay | SP210 | 37kg | 2100 long, 80 x 80 cross section | 400W x 600L x 350D |
| Intermediate | IP210 | 37kg | 2100 long, 80 x 80 cross section | 400W x 400L x 550D |
| Type | Code | Mass | Nominal Dimensions (mm) | Footing Size (mm) |
|---|---|---|---|---|
| Major | M240 | 76kg | 2400 long, 115 x 115 cross section | 500W x 500L x 600D |
| Stay | SP240 | 42kg | 2400 long, 80 x 80 cross section | 400W x 600L x 350D |
| Intermediate | IP240 | 42kg | 2400 long, 80 x 80 cross section | 450W x 450L x 600D |
| Type | Code | Mass | Nominal Dimensions (mm) | Footing Size (mm) |
|---|---|---|---|---|
| Major | MP270 | 86kg | 2700 long, 115 x 115 cross section | 450W x 450L x 600D |
| Stay | SP270 | 46kg | 2700 long, 80 x 80 cross section | 400W x 600L x 350D |
| Intermediate | IP270 | 46kg | 2700 long, 80 x 80 cross section | 400W x 400L x 550D |
| Type | Code | Mass | Nominal Dimensions (mm) | Footing Size (mm) |
|---|---|---|---|---|
| Major | MP300 | 95kg | 3000 long, 115 x 115 cross section | 500W x 500L x 600D |
| Stay | SP300 | 51kg | 3000 long, 80 x 80 cross section | 400W x 600L x 350D |
| Intermediate | IP300 | 51kg | 3000 long, 80 x 80 cross section | 450W x 450L x 600 |
Technical drawings
Refer to our technical drawings page for detailed dimension and installation information.