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Why do manufacturers make ridiculous claims?

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Why do manufacturers make ridiculous claims? RicodJour 06-18-2007
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Posted by Dennis on June 20, 2007, 9:39 pm
Most of the responses you are reading here appear to be from kids who are
not associated with engineering nor with how engineered products are
marketed (note the off-topic preoccupation with the falsely-accused Duke
Lacrosse college kids).

Some are arguing that the underlying soil is not strong enough to support a
truck, which is of course ridiculous. The substrate conditions would be
engineered to take the assumed reactions necessary, while the manufacturers
product is design to provide a soil base and drainage stratum. It is assumed
that the underlying soils would be considered in any installation, and
improved if needed. This product's advantage is only in the addition of
adding grass to such areas; already deemed capable of withstanding the
loading of vehicular traffic.

Reviewing the test reports provided, it appears to me (my opinion) that the
testing performed by the University of Southern Mississippi is completely
within established guidelines and have sufficient credibility. The only
additional qualification I would ask to see is the signature of a licensed
professional, registered in the state where the tests were conducted or from
the state where the product is manufactured. I work in plan review for a
nationally recognized testing laboratory and review test reports similar to
this product, on a regular basis.

As always, the best results is the feedback from existing installations. If
you still have any concerns over the product's durability, I would recommend
contacting the manufacturer to see what problems and failures are occurring
in the field.


> Good Morning,
>
> Interesting thread.
>
> http://www.grassypavers.com/MPI%20Study%20Data%20and%20Explanation.pdf
> ot http://www.grassypavers.com/specs.htm and select the load data
> sheet link.
>
> While I'm not the sharpest tool in the shed, I do like to hear good
> feed back on the products I sell. I am a dealer for the product and I
> own the site http://www.grassypavers.com. I use data given to me for
> the site. If it is incorrect I would like to update the info so it
> correctly represents the product.
>
> You guys obviously know your stuff in the load arena. I would love
> some feedback on this load data from MPI. Is it crap? if so why? This
> is where the facts come from we use on the site (actually from the 4
> page brochure on the specs page). I will be glad to send samples out
> to anyone that would be willing to conduct these tests to see how our
> products hold up.
>
> I would also be willing to take feedback and a real world writeup on
> soil load capacities and what benefits any kind of pavers provide for
> that soil base.
>
> I want everyone to know about the product and I want that info to be
> correct. Architects, Designers and End users a like should have
> factual information in making decisions and choosing products.
>
> So I hope ya'll don't still want to take out behind the shed. My goal
> is to provide factual data for our products. They are a good solution
> and are more durable than people think.
>
> Please keep up the thread. I like a good debate.
>
>



Posted by RicodJour on June 20, 2007, 11:30 pm
> Most of the responses you are reading here appear to be from kids who are
> not associated with engineering nor with how engineered products are
> marketed (note the off-topic preoccupation with the falsely-accused Duke
> Lacrosse college kids).
>
> Some are arguing that the underlying soil is not strong enough to support a
> truck, which is of course ridiculous. The substrate conditions would be
> engineered to take the assumed reactions necessary, while the manufacturers
> product is design to provide a soil base and drainage stratum. It is assumed
> that the underlying soils would be considered in any installation, and
> improved if needed. This product's advantage is only in the addition of
> adding grass to such areas; already deemed capable of withstanding the
> loading of vehicular traffic.

A lot of words that don't say very much, and what they do say is
misleading.

Obviously the product is intended for creating a drivable green
surface. Thanks for clarifying that - the name grassy paver had
confused me.

"It is assumed that the underlying soils..." That's your idea of
engineering? ASSuming bearing capacity and soil conditions?

An 18 wheeler typically weighs in at around 80,000 pounds maximum load
(federally mandated maximum).
An average semi tire has approximately 60 square inches of contact
area - that's ~7.5 SF of tire contact area per truck, or roughly
10,000 PSF.

If that grassy paver stuff has a rating of TEN times the maximum load
allowed on federal highway - with the graded, layered and compacted
base - why the nifong do they use asphalt and concrete for roads?

Your grasp of the numbers is as faulty as the manufacturer's claims.
Move on - please. This is getting embarrassing.

R


Posted by Dennis on June 21, 2007, 8:01 pm
> Its doubtful that piece of plastic will support 97,000 pounds, regardless
> of what's supporting the plastic.

With gravel on the bottom, inside the hex spaces and on top, how much load
do you think the plastic forms are actually carrying?



Posted by Tony on June 21, 2007, 10:25 pm


> With gravel on the bottom, inside the hex spaces and on top, how much load
> do you think the plastic forms are actually carrying?


it's the weakest link principle

don't pay me no mind, Im just agreeing with you

Tony

why he keep asking about the damn gravel
now if his HEAD was in the plastic, yeah, maybe 100G

just kidding!




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Posted by Bobk207 on June 20, 2007, 2:09 pm
>
>
>
> > There's a new trend to develop green roofs (covered with grass). Used on
> > some commercial buildings made to be walked on by the tenets, also used to
> > make a roof greener for a penthouse. That's where I've seen these types of
> > products used, but not to any real extent.
>
> > As far as the loading goes, did you see that its designed to use a base of
> > 6-7 inches of stone aggregate, covered with a bed of gravel 2' thick, with
> > the hollows filled with pea gravel covered over with a 6" sand cover. The
> > plastic pavers are used as a stabilizer for the gravel.
>
> > There should no problem in carrying a load of 675 psi using the method
> > advertised on the website. I don't think you read through the entire
> > specifications completely.
>
> > As far as what they advertise for loading, 674 psi is high, but not unheard
> > of.
>
> Forget left field, you've jumped the fence and are hanging out in the
> bleachers. Typical undisturbed prescriptive lsoil bearing capacity
> loads, according to the IRC, are in the range of a ton or two per SF.
> In other words, their paving plastic grid, resting on gravel (assume
> five tons PSF bearing capacity for gravel to show I'm not being
> unreasonable), increases the bearing capacity by TEN times. That
> sound right to you? If so, I sure hope you don't do your own
> calculations.
>
> R

RIco-

I visited the website & emailed the guy (he posted below) about the
claims being made.

He sent me a link to some info from the mfr (he jut sells them)

looks like the mfr had some tests done on the plastic unit (filled &
un-filled) AND the mfr (or their agent) did some hand waving based on
the ASSTHO H-20 loading

And then extrapolated the results to some of insane psf number

the guy who signed the test report is some sort of clueless
Phd.......reporting numbers with 6 or 7 "significant" figures,
reporting psf's that no soil in the world could possibly support


Using the ASSTHIO loading & then extroplating to a generalized psf is
like calc'ing the stress under a woman's high heel & extrapolating to
a psf for floor loading!

Example:

120 pounds, assume .375" diameter heel tip, standing equally on both
shoes,

540 psi translatesto >>>>>> 78,200 psf

makes as much sense as their test report & product claims

What they really have is a product that can take a higher "point
load" (actually a local small patch distributed load) than normal
(unconfined / un-reinfornced) soil.

With the plastic grid & grass roots, you wind up with a reinforced
soil that (IMO) is at best is a few times stronger (locally) than
regular soil MAYBE 20 or 30 psi

but it ain't asphalt or concrete!

cheers
Bob


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