Testimonials > Tests
Background
Generally vineyard posts are categorised into two types depending on the application, i.e. ‘Major’ structural posts and ‘Intermediate’ posts. Traditional vineyard fencing has been a mixture of timber posts (major and intermediate) or a combination of timber (major) and steel (intermediate).
Tristar Fencing have enhanced their steel posts to use in vineyard trellising as major and intermediate posts. CSIRO was commissioned to look at the performance of Tristar posts in comparison to the other posts used in practice.
Specimen Description
| Type | Specimen | Dimensions | Description |
| Major | Treated Pine | 2400mm x 100mm diameter |
Round |
| Major | Hardwood | 1800mm x 100mm x 100mm |
Square |
| Major | Tristar (Ramshead post) |
2400mm long | Combination rolled sections |
| Intermediate | Tristar ‘Vee’ post | 2400mm long | Rolled section |
| Intermediate | BHP Steel | 2400mm long | Rolled section |
| Intermediate | D&N Vinstakes | 2400mm long | Rolled rectangular section |
| Note: 1800mm long square hardwood posts were tested with 450mm embedment while all the other posts with 600mm. | |||
Configurations of Tested Fence Posts
Test Conditions
Posts were tested in a cantilever mode. 600mm length of the post was restrained (except for hardwood posts which were restrained over 450mm length) and a gradually increasing load was applied at the free end.
Exact simulation of the forces acting on the posts buried in the ground would be extremely difficult. Hence, a simple supporting mechanism was adopted by restraining the foot of the post, and the point of exiting the ground.
Test Results
Flexural Strengths of Posts (’Major’ Category)
‘Intermediate’ Category Test Results
Flexural Strengths of Posts (’Intermediate’ Category)
Major Category Conclusions
In the case of ‘Major’ type timber posts, the following may be stated.
- In practice timber posts are being used satisfactorily.
- Field failures have been reported.
- Natural material defects are unavoidable.
- Deterioration due to rot and ageing is not uncommon.
In the case of Tristar Ramshead posts, the following may be expected.
- Material variability is low.
- Geometry variation can be minimised.
- Ductility is relatively high.
Therefore, the predicted design values for the Tristar Ramshead posts may be used with confidence.
Overall Conclusions
Tristar posts can be successfully used in vineyards within the recommended wind speeds. It is also understood that the extremes of wind speeds are only expected at the outer three rows of trellis on the windward direction and that the wind loads on the majority of vines may be much less due to the shadowing factor. Therefore, posts may be spaced out 30% further on the inside rows of trellis.
A complete copy of our test results are available on application.