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Re: Unreinforced foundation walls

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I believe  prescriptive "charts" or other informtion are prepared for lay
people and other non-engineers to use. When they hire an engineer it is
expected that engineering methods will be used to determine how to build
a structure that will resist all the reasonably expected forces.
I would not look forward to trying to defend myself in court regarding
failed basement walls that I was responsible for, by saying that a chart
indicates that it is OK. The attorney would likely say "didn't you say
you  have a degree in engineering? why didn't you use it?"  I also don't
think it would work well to use the quote that someone has previously
said that "engineering and science don't apply to basement walls". This
type of thinking seems to me to be similar to using 2x4 rafters- they
work Ok if no snow and no one gets on the roof.

Stan Scholl, P.E.
Laguna Beach, CA

On Fri, 04 Feb 2005 10:31:01 -0500 "Jordan Truesdell, PE"
<seaint(--nospam--at)truesdellengineering.com> writes:
> When you say "look at the charts", I'm assuming that you have some 
> data on 
> the soil type, and are reading the charts for silt or clay backfill? 
>  I've 
> yet to see a contractor read beyond the GW/GP column in those 
> charts, then 
> backfill with whatever is onsite. Further, most code officials I 
> know don't 
> know enough soils mechanics to understand that CL and GW are not 
> interchangeable for load purposes.
> 
> And, for the record, I've seen a cracked basement wall that was 8' 
> high 
> with 6' of backfill, made of 8" unreif. cmu. By the code,
> 8" is the correct thickness, up to low placticity silt backfill 
> (ML). 
> Without proper equipment, there is no way for lay-person in the 
> field to 
> determine the difference between ML and ML-CL, which would have 
> required a 
> 10" cmu.
> 
> Jordan
> 
> 
> At 09:17 AM 2/4/2005 -0500, you wrote:
> >Again I will say that you, my engineering brothers, mainly 
> commerial 
> >engineers will have to get over doing the engineering on 
> unreinfoced block 
> >and concrete walls.  As I am fond of saying "Don't take my word for 
> it, 
> >let's look at the code." I have looked at hundreds of these cracked 
> walls 
> >and everytime the wall is undersized per the code charts., any 
> codes.  The 
> >charts work when applied. I still deal with engineers and 
> contractors that 
> >think horizontal reinforcing will help, it does nothing.   I will 
> agree 
> >that there is a little voodoo when it comes to the connection 
> between the 
> >plates and joists, but i have never seen a wall that follows the 
> charts fail.
> >
> >Jeff Fertich, PE
> >Gettysburg, PA
> 
> 
> 
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