View Full Version : Commercial Retaining Wall Spec Warning

04-17-2001, 08:07 PM
I was at my local landscape assoc meeting last night, and found out that it was a good thing I didn't bid that big retaining wall for Wal Mart a few weeks ago..

I never bothered to look at the block specs, assuming that the block mfgs here made their block to the specs laid out by any architect. You know what they say when you assume.

Here's what I found out and how it may affect you:

In the state of Minn, there are some Versa-Lok walls along highways. The blocks at the base of these walls are showing a lot of abnormal wear. They're finding it to be due to the blocks propensity to hold onto road salts longer than concrete in a poured wall. There may have even been a lawsuit, I'm not sure.

Anyway, the state of Wisconsin DOT, not wanting to have similar walls along their highways degrade in a few years, has created NEW specs for segmental retaining wall units. The previous specs for almost any job state that the block must have 4,000 PSI strength. Our new DOT specs require 6,000 PSI. What's more, rather than the usual 30 freeze-thaw cycle test they must pass, the DOT now requires 100 freeze thaw cycles, without the blocks strength degrading. And the mfg must guarantee the block for 75 YEARS!! Right now there are only a few block mfgs that can even make block to these specs.

You're thinking, so what does the WI DOT specs have to do with anything? How does that affect me in IL, MI IN or wherever? Well, architects, wanting to give business owners like Wal-Mart the best retaining walls they can, are using these WI DOT specs for their walls. Why not? They can boast to their customer "Look, I'm going to put some walls in for you that're guaranteed for 75 years!!" Which means you can expect to pay double the price for block, because they have to be a special run for these specs, and an added charge to guarantee them for 75 years.

So, had I placed a bid and won, I'd have lost my shirt on materials prices, because that's the kind of block they spec'd. And I didn't catch it.

Now these WI specs may not make it to your state, but architects often create plans for facilities in other states......So, YOU'VE BEEN WARNED!!

[Edited by Stonehenge on 04-17-2001 at 07:12 PM]

04-17-2001, 08:45 PM
Thanks for the heads up. I certain the same thing will start to happen in MI. We salt the bejeebers out of everything arround here. Once problems start to crop up MI will allmost certainly adopt your new standards.

Can you tell me which manufactures carry the block that can pass the tougher tests and if there is a special lableling, ie. meets ??? spec, for the tougher block.

Jim L

04-18-2001, 07:13 PM
Sorry, I can't give you any more info than what I did. County Concrete, a WI mfg of Versa-Lok and other block, is now able to do it, but it's a special order item, usually with a minimum order of 5,000 units. From what I know of the other WI mfgs, for any special order, 5,000 block is the usual min order.

John Allin
04-18-2001, 09:10 PM
Missing something like that on teh spec could HURT....

04-18-2001, 09:22 PM
Just to add My 2 cents here, Spent the day checking block manufactures in my area, 2 have material that meets or excededs the 6000 psi, one carries them as standard units, the other makes them on special order, with no price increase. It seems the larger faced block manufactures are having problems meeting the new specs. On the whole it seems that the new specs will remove some manufactures from bidding on State Hwy projects. It appears that the machines that make the larger faced units can't reach the compressive strength, these machines are of the concrete block type not the paver type.

04-19-2001, 02:58 PM
Thanks for the info. If I hear anything regarding new MI specs or block I will be shure to post.
Jim L