Let me run this idea by you. How about a quick reference chart indicating the ground pressure in # psi. No more guessing. No more wondering about what it really is. If an operator was armed with these tools he would know.

For my example I will use 38,000 # as the number on my example outrigger and I will use 4 foot long 4” x 6” as my dunnage supply.

You should use the highest number on your outriggers as your load and whatever dimension your dunnage will be. The 4 ft 4x6 is a good size.

6” width x 48” length will give us the square inches of one of our boards. 288 square inches per each 4x6.  Two of them are 576” sq.

576 also just happens to be the same amount of square inches as a factory 2 foot square pad. So there would be no sense putting 2 of them under a factory pad because you would gain nothing. So the place to start our chart is 3 pieces.

OK, lets start our chart

Your factory pad = 576  (square inches)

3 =  864

4= 1152

5= 1440

6= 1728

7= 2016

8= 2304

Now we divide our load – down pressure – by each number to get the ground pressure (as # psi)

38,000 divided by 576                                66#psi pad only

38,000 divided by 864                                44#psi  3pcs 4” x 6” x 4 foot (oak)

38,000 divided by 1152                              33#psi  4pcs

38,000 divided by 1440                              26#psi  5pcs

38,000 divided by 1728                              22#psi  6pcs

38,000 divided by 2016                              19#psi  7pcs

38,000 divided by 2304                             16#psi  8pcs

If you operate a 36m putz – 38m putz – 40m putz

The chart in the red print is for you. Just copy and paste

It to your documents somewhere and print a copy and

Put it in your pump. You will always know where you stand.

Everyone else gets to do his own chart. Just substitute

The number on your outrigger (where I have 39,000)

And divide to find the soil load by number of pieces.

I hope that you will take a few mins’ to do this.

It may really open your eyes.

Don’t bullshit yourself

bob, could you please convert that to english metric.

Sergei , just the pic I was looking for to post here !

It says how much dunnage y2 or m2 you need on different groundcondition .

Sergie - Vasa...

I'll '3rd' that...

All the ground pressure charts are right there on the outrigger leg.

Sergie, Vasa & Raymond

Yes, it is there.

Does anyone except the few of you actually read, and go with those recomendations? As far as I can see, you are out numbered by those that either dont' know or don't care

http://concretepumping.com/index.php?mode=photo_album&act=view&pho_id=3&p_id=1466

the question is how whell do you know the ground condisions in this case 5000 square inch would't be enough