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Re: Water reservoir - joints, wall ties, and alternate pours

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Thanks for the advice, Ibrahim.  
Where can I get info on snap ties with water stoppers?
I have never seen them, and I can't find them on the web.

Why would you use more than a bond breaker between the walls?  Do you
think that just the bond-breaker will not suffice to force a crack
location?

Kevin

From: "Ib sa" <ieseng(--nospam--at)msn.com>
To: seaint(--nospam--at)seaint.org
Subject: Re: Water reservoir - joints, wall ties, and alternate pours

Snap ties with water stoppers should be used for the wall forming. Also
I 
would use more than a bond breaker between the walls maybe 1 to 2
inches.
Ibrahim

>From: "Kevin Below" <kevin.below(--nospam--at)sympatico.ca>
>Reply-To: <seaint(--nospam--at)seaint.org>
>To: <seaint(--nospam--at)seaint.org>
>Subject: Water reservoir - joints, wall ties, and alternate pours
>Date: Thu, 14 Mar 2002 17:47:31 -0500
>
>I am designing my first water-retaining structure - a series of 3 
>underground rectangular tamks, each 20m x 20m x 2.5m deep with 355mm
>(14") wall thickness. We have 60 degrees Celsius range of temperature 
>here in Quebec. The total length is thus 60m, which is a long way to go

>without joints. But I would like to avoid joints like the plague, so I 
>have elected to use a separate structure for each tank. So I have a 
>double-wall between the tanks, with the intention to pour the walls of 
>one tank, apply a bond-breaker on the face of the common wall, and then

>pour the second tank, and so on.
>I don't like it, because it complicates the wall ties for the second
>wall of the double-wall section. And then I have to cover the joint
>with flashing to keep out the water in our freeze-thaw climate. But the
>experts in my books seem to agree that no joint is a good joint,...
well
>maybe construction joints are a necessary evil and can be done well.
>
>What do you think? Is it better to separate the tanks as I have 
>proposed, or to simplify the construction and add a joint or two ?
>
>What do you do with the wall ties ? Do you use conical ends, and patch 
>the holes? Will non-shrink grout do the trick?
>
>What about pouring the wall in alternate sections, leaving short 
>sections to infill after a week or two? Is it worth it?
>
>I have been researching this and doing my calcs for 3 days now, and I 
>have accumulated a lot of notes from my references, but they can't 
>answer everything I guess... I have heard horror stories of engineers 
>in court because of leaky tanks, so I am very wary. One reference I 
>use is in a chapter on water-retaining structures by B.P. Hughes at the

>University of Birmingham. He mentions the importance of limiting crack 
>widths to 0.1mm (0.004"), which usually controls the design. And so it 
>does in this case. Steel stresses are way down at about 50 MPa (7,000 
>psi). Interesting. It's very different from buildings.
>
>Kevin Below
>Génécor inc., experts-conseils



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