Diamond Pier System

[msquared48]

http://www.diamondpier.com

Anyone have any experience, good or otherwise, with using this system?

Workmate has a project to design a boardwalk in a wetland area with a seismic D class in clay/sand, as opposed to using pin pile driven to re3fusal at 20 to 25 feet.

I am concerned about liquefaction of the soil mass and the behavior of the system in such an environment. The geotech we are dealing with helped develop the system... I am also concerned with the possibility of vertical settlement. The only attachment appears to be a binding or pinching force of the pins to the concrete head coupled with interstitial friction. I see nothing physically locking the pins to the head, only a seal cap to prevent water intrusion from the top, which is academic in my opinion as it could intrude from underneath and cause a freeze/thaw action.

Mike McCann, PE, SE

 

[BUGGAR]

I share your concerns. They seem to be relying on bending of the pins, at least to some extent. We worked with SDG&E on their Sunrise Powerlink (shameless brag). Their tower legs were supported on elaborate plate fabrications which acted as templates for multiple pin piles, like large fancy versions of your concrete block. Ours, however, relied on axial compression and tension in the pins only, no bending. And the Pins were actually grouted to the plate structure in a sort of grout-filled chamber (no torch work allowed where they were building these things.

The pins on the proposed system don't seem to carry the loads below 63 inches or so but they may be creating a large pressure bulb?

I vote for a test. Why is there no reference to the Geotech in the video literature?

Bob

 

[capeengineerma]

In our area, the local lumberyard is pushing these for deck post supports. They seem to work well when driven into frost free (fine to coarse sand) material. The literature provides bearing capacity and frost protection depths based on the length of the rods. You are correct, there is no positive connection between the rods and the concrete mass. The bearing capacities are generated by friction between the soil and the rods with some additional bearing in the soil due to the driven angle. I would be concerned with freeze-thaw action if in materials that are not well drained. You are also in for difficulties if there are any cobbles or rocks greater than 3" in diameter since you use a Pneumatic hammer drill to drive the rods and it doesn't take much to get refusal.