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RE: Buried Concrete Structures

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I agree with the idea of adding struts if it is rectangular - also add
belt beams, i.e. horizontal stiffener beams at the same level as the
struts. If circular, the compression of the cylinder should negate the
need for struts. 

But I would never design such a structure for less than at-rest soil
loads - the box shape, struts, and thick walls would prevent adequate
deflection to develop active earth pressure. Actually, at this depth you
are likely to also encounter groundwater - so the lateral earth pressure
should be on the order of 90 pcf, unless you can drain to a lower
elevation or provide a pump system with redundancy and backup power. 

I've designed such structures and, yes, the walls get thick. 


-----Original Message-----
From: Stanley E Scholl [mailto:sscholl2(--nospam--at)juno.com] 
Sent: Friday, April 08, 2005 10:05 PM
To: seaint(--nospam--at)seaint.org
Cc: seaint(--nospam--at)seaint.org
Subject: Re: Buried Concrete Structures

Suggest that in addition to making it round that you consider horizontal
struts every 10 ft. ht. or so, and using drains outside to collect water
and relieve pressure by collecting drainage and pumping it to surface
for draining away from site- thereby using perhaps 35 #/cu. ft. EFP.

Stan Scholl, P.E.
Laguna Beach, CA

On Fri, 8 Apr 2005 16:07:53 -0700 "Lutz, James"
<James.Lutz(--nospam--at)earthtech.com> writes:
> If you have a choice, make it round.
> 
> -----Original Message-----
> From: Acie Chance [mailto:achance(--nospam--at)lacsd.org]
> Sent: Friday, April 08, 2005 3:31 PM
> To: seaint(--nospam--at)seaint.org
> Subject: Buried Concrete Structures
> 
>       I am designing a concrete structures for a pump stations which 
> is going to be buried very deep.  The structures will be 50 feet below

> grade.
> The structure will be 80 feet by 50 feet.  The references I have found

> around the office date to the late seventies and early eighties.  If 
> any one has anything newer I would like to know about it.  Of 
> particular concern is the soil loading to the structure.  If I design 
> for Atrest pressure (60
> #/ft.^3) the side of the structure will be thick.  I would like to 
> know of any technical references and/or experiences any one out there 
> has had.
> 
> Thanks
> Acie Chance
> 

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