Last updated 24th May 2022
Not sure what part of Australia you live in, but we live in the Northern Rivers region of NSW. It has been raining pretty much since December last year (2021) around here.
We've been waiting since December to carry out in-ground pull out testing of all our products in dry ground. Recently though we were contacted to have our products tested for a solar farm installation and didn't matter if the ground was wet or dry but for the tests it was probably best wet, because that's when the ground is softer and takes less to pull out ground anchors, stakes or pegs.
We took along our prototype GR14 range and some other even larger prototypes which as of the date of writing this blog are unavailable for retail sale. If you would like to order some or know more please contact us.
It was a typical rainy and cloudy on & off kind of day. We met on site in Wardell. The installation is to go nearby for Ballina Council.
Susu and I met the testing team and watched as they were screwing down large pile ground anchors about 2m long with a hydraulic drill attached to the front of a mini excavator machine.
The large 2m screw piles made our GroundGrabba's look like tooth picks!
When they'd completed their tests on the screw piles it was our turn.
First I tried driving in our new prototype samples of 75mm diameter auger and then the 180mm even larger auger into the ground.
We could drive the 75mm into the sandy ground but could only drive the larger 180mm down to just below the auger flights. We also had much trouble extracting both of them. Back to the prototype drawing board for these ones!
The 75mm drove in well and held well over 600 kg in this substrate.
The 180mm didn't go full depth and therefore held very little upwards tension but almost pulled up a huge chunk of soil with it.
Next we tested two of our GR14 commercial samples.
Our GR14 commercial GroundGrabba's come in three lengths:
- GR14S 450mm
- GR14M 600mm
- GR14L 900mm
GR14M and GR14L shown above.
Designed with a 25mm Hex Head with larger 40mm diameter flange collar.
The 25mm hex head is 20mm high and our test samples have a 10mm hole running side to side for use with bow shackles etc.
Below is the GR14L 900mm being driven into what appears to be sandy dirt. When driving these downs it is easy to tell that the substrate is not the same all the way down. It varies from the GroundGrabba drawing itself down to other times where downward force is needed.
Note that the Makita DTW1002Z Impact wrench being used has a nut busting 1600Nm of torque. The GR14 models are not toys and you'll need a heavy duty high torque driver much like this or the higher rated Milwaukee M18 ONEFHTWF1.
GR14S 450mm shown below. The GR14 is made to screw through a hole diameter of 30mm through material up to 8mm thick.
We didn't bother testing our GR14S 450mm ground anchor at the sandy dirt site because the substrate being so soft on the surface there'd not be enough depth of reach to provide adequate anchoring.
Both the GR14M and GR14L performed well with the GR14L readings in excess of 750kg.
Here is a video of the pull out testing for the GR14L 900mm at Wardell which had sandy dirt substrate.
Keep in mind we were not testing for maximum hold, only for passing the engineering specifications set for this particular solar farm installation.
Things that need to be considered to pass the tests are vertical movement and lateral movement or in other words lift out anchoring hold and sideways movement in the ground. For lateral movement tests, it is the wider diameter shafts that offer less movement compared to narrower shafts.
Next we headed off to another site in a little regional town called Alstonville where the ground was completely different.
On this site was grass on top of compressed or compacted rubble and dirt with many rocks of all sizes. In past days there was construction on this exact area which was demolished and the heavy machinery movements plus rehabilitating the site created a substrate which to me was anything but normal.
First I drove in a GR14S 450mm and I could really feel it bite quite well. Next was the GR14M 600mm and it was not easy getting this in. I had to poke and prod around until I found a spot that allowed it to go down to full length. It bit into the ground REALLY well.
This video doesn't show my first failed attempt at screwing the 450mm GR14S in as it hit an underground obstruction. So I moved the position and tried again but this time finding a gap in the rubble below. I was lucky with the GR14M 600mm and found a spot straight up but could feel that the last 300mm of substrate was harder/different and slowed down driving quite a bit.
There's no video of us trying to deploy the longer GR14L 900mm as I couldn't get past the 600mm mark due to the amount of rubble underground.
There is, or was the potential of drilling a pilot hole which we didn't do.
The results from the 600mm version surpassed the engineering spec's.
The video below is pull out testing of the 450mm GR14S at Alstonville site with mixed dirt and rubble substrate... It achieved a remarkable maximum peak of about 440kg.
Now for the GR14M 600mm... which peaked at a whopping 876kg
There was another type of ground anchor (below) made of cast aluminium to test however this particular product pulled out virtually by hand. In this image both a new and old one are side by side. Notice the wear.
The old one has been commercially used for event tent set ups. The aluminium hex head is almost rounded and the threads have worn down substantially.
For one-off installations there'd be minimal loss through wearing of the aluminium but for commercial day to day use, wouldn't you want to use steel? All GroundGrabba Pro ground anchor products are heat treated carbon steel.