Recommended Method for Driving Concrete Posts in the Ground
The prestressed concrete fence post is designed for tough conditions and are driveable with a standard post driver.
Percussion drivers. pneumatic drivers and standard thumpers are all able to be used to drive the concrete fence post.
Australian Concrete Posts recommend that a thick rubber material be used to cushion the direct impact on top of the post when driving them in. Australian Concrete Posts have designed a driving cap to be placed on top of the post. Before ramming in hard ground we recommend a pilot hole.*
Recommended method to hit in a concrete fence post
- Drill a pilot hole about 150 to 200mm (6 to 8 Inches) wide to the depth you require the post to be placed into the ground
- Ensure the pilot hole is vertical
- In drought conditions wet the post or the ground with about a litre of water. (Old fencers trick to make the concrete post slide into the ground easier).
- Place the driving cap with the appropriate rubber over the post to prevent the metal driver hitting the post.
- Gently tap the post into the ground using small strokes of the driving hammer. Refer to the table below that shows the recommended height the driver hammer should be lifted to depending on the hammer head weight.
HEIGHT HAMMMER HEAD LIFTED TO MATRIX
The table below shows the recommended height the driver hammer should be lifted to depending on the hammer head weight.
|HEIGHT HAMMER HEAD LIFTED TO|
|300mm or 1ft||600mm or 2ft||900mm or 3ft||1200mm or 4ft|
|WEIGHT OF HAMMER HEAD||180kg or 400ld||529kg||1.1 ton||*1.6 ton||2.1 ton|
|272kg or 600lb||800kg||*1.6 ton||2.4 ton||3.2 ton|
|362kg or 800lb||*1.1 ton||2.1 ton||3.2 ton||4.2 ton|
|450kg or 990lb||*1.3 ton||2.6 ton||3.9 ton||5.3 ton|
|*ACP recommended heights and weight ratio and settings|
In some circumstances you are able to hit the posts directly into the ground without using a pilot hole. This will depend on numerous factors like soil condition, how wet the soil is, if there are rocks, your experience at driving the concrete posts into the ground and the way you use your driving hammer. Therefore, we recommend you use a pilot hole which is drilled vertically to the depth you require the concrete posts put into the ground.
What about in rocky country?
If you’re in rocky country, then by using a pilot hole you can judge the depth the post can go into the ground by the depth of the pilot hole drilled.
Remember concrete is not like timber where you just hit the post into the ground and cut the top off and drill the holes.
You have to think backwards and cut the bottom of the post off, to the required length before hitting into the ground. Therefore, measure how deep the pre-drilled hole is and cut the bottom of the post off.
Cutting the post to the desired length is easily done using a concrete cutting blade on a grinder. Click to get some tips on how to on this link.
Driving Concrete Posts with Pneumatic & Percussion Drivers
Driving Caps for Pneumatic Drivers
Pneumatic and percussion drivers need a manufactured driving head. The ACP Driving cap is not suitable for a percussion driver.
Every percussion driver is a different type of post guide, essentially will need to customise your post guide to hold a thick piece of rubber or polyurethane between the head of the post and your driver to minimise the direct impact on top of the post. Below are some options Elgra or Munro Driver that some customers have customised for their drivers.
MUNRO & El-GRA DRIVERS
Visit your local Munro dealer or website to find information about using a Munro or El-Gra Driver on your prestressed concrete posts.
Here are some helpful tips on how to use your Elgra and Munro Driver with concrete posts.
- You will need to adjust, (usually turn down) the Rebound pressure on your percussion drivers to suit driving concrete fence posts.
- Essentially your MUST ensure there is a heavy duty belt rubber or polyurethane layer between the post driver head and the top of the post to minimise the violent impact on the posts.
- Below are some examples using an El-Gra Driver that some of our customers have adapted for their drivers.
- Watch this video that demonstrates how to adjust pressures with a Munro Post driver.
- Watch this video that demonstrates how to adjust pressure with an El-Gra Driver
- Click this link to go to Munro Drivers web page
- Click this link to go to El-Gra Drivers web page.
COMMERCIAL DRIVING CAP
Paul Nielsen Hydraulics in Ballina NSW can manufacture a driving cap to suit your post driver. Contact Paul Nielsen Fabrications & Hydraulics Telephone: 02 6681 1155. Their website: http://fabricationballina.com.au/ . An example of driving cap manufactured by Paul Nielsen is pictured below.
Watch how posts are driven using a pneumatic driver with custom built driving cap.
More How To's
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