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Re: [Shop-talk] Engineering question

To: shop-talk <shop-talk@autox.team.net> OsQq+HSQluVgzhSpYuMrz8/hwBlavEPetAjDu5Au9Q5t12aP+xXY/lM4+ey5wd6I+cT/wPpAlorOuE+Cxs9etV4OR66xeYEyW8sRnwVwrBdnEN414m/SzMrH QT7YwjEvCSA7hLZfYRuRKw==
Subject: Re: [Shop-talk] Engineering question
From: Brian Kennedy <kennedybc@comcast.net>
Date: Sun, 27 Nov 2016 17:44:50 -0500
Delivered-to: mharc@autox.team.net
Delivered-to: shop-talk@autox.team.net
References: <20161127.154831.7282.0@webmail13.vgs.untd.com> <CANuE7YCjieEODxi0020PVPYp=F58qL8=vzGOZHLwuEeKjvUq0w@mail.gmail.com>
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I looked at a photo online. Straps are about 1/4 of the length from the =
end which is where I would think you'd put them to minimize the bending. =
Hard to believe that your static stresses would be anywhere near close =
to what the tanks would see on an 18 wheeler pounding down the road.
Brian in MI




On Nov 27, 2016, at 4:45 PM, John Innis <jdinnis@gmail.com> wrote:

> Yes, truly an engineering question.  It has been many years since I =
was in engineering school.  But I know the answer to this one.  You have =
not provided enough information to answer the question.  We would need =
to know the wall thickness of the tank and type of aluminum.  Measuring =
the wall thickness should be pretty easy, but figuring out the grad of =
aluminum may be very difficult.  I suggest giving up on the engineering =
and resort to shade-tree mechanics.  Use a piece of 3/4" plywood and cut =
a radius in it to match the tank, then bolt this between the upper arms =
of the 4x4 to make a cradle.  Stack enough pieces of plywood together to =
match the width of the strap used on the truck.  You know that method =
was sufficient under the dynamic load of a moving semi.  Should be more =
than adequate for a stationary tank.  It also has the added benefit of =
tying the 4x4's together at the point of load, so outward bending =
stresses will be reduced.  Your 4x4 x ' should be fine as long as you =
use through bolts of adequate size to join the together in the middle =
and to bolt the ties at the base.  To help insure the load on the 4x4's =
are minimized, you should cut the bottom ends to match the angle, so the =
sit flat on the floor. =20
>=20
> On Sun, Nov 27, 2016 at 2:48 PM, Matt <mbarre@juno.com> wrote:
> I hope you all had a great Thanksgiving and have plenty to be thankful =
for!
> =20
> I am adding diesel storage capacity to my shop.
> I got a good deal on an aluminum semitruck fuel tank ( 26" diameter  =
68" long) and need to construct a stand for it.
> These are normally secured on the truck with metal straps or bands.
> =20
> For my stand I am considering constructing large "X" from pressure =
treated 4x4 and resting the tank in the upper V.
> I would tie them together with 2x4 s to keep them from cocking.  I =
figure I would be safe with 3 Xs if any doubt, 4 to make sure.
> =20
> Question:  If I went with only 2 supports and kept them out on the =
ends, would the bending moment (bowing) threaten the integrity of the =
tank?
> 150 gallons is about 1000#.  Similarly, would the reduced "contact =
patch" of X mounts vice continuous straps threaten the tank walls?
> =20
> I am sure I could dig out my old Statics book and find the equation, =
but don't have a design bending limit for the tank.
> I am anticipating that just 2 supports, especially out at the ends =
would be too risky.
> =20
> =20
> Thanks for your thoughts,
> Matt in GA
> =20
> =20
>=20
> _______________________________________________
>=20
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http://autox.team.net/mailman/options/shop-talk/jdinnis@gmail.com
>=20


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<html><head><meta http-equiv=3D"Content-Type" content=3D"text/html =
charset=3Dus-ascii"></head><body style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; ">I =
looked at a photo online. Straps are about 1/4 of the length from the =
end which is where I would think you'd put them to minimize the bending. =
Hard to believe that your static stresses would be anywhere near close =
to what the tanks would see on an 18 wheeler pounding down the =
road.<div>Brian in MI<br><div apple-content-edited=3D"true">
<span class=3D"Apple-style-span" style=3D"border-collapse: separate; =
color: rgb(0, 0, 0); font-family: 'Times New Roman'; font-style: normal; =
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-webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; =
font-size: medium; "><div style=3D"word-wrap: break-word; =
-webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><span =
class=3D"Apple-style-span" style=3D"border-collapse: separate; color: =
rgb(0, 0, 0); font-family: 'Times New Roman'; font-style: normal; =
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white-space: normal; widows: 2; word-spacing: 0px; border-spacing: 0px; =
-webkit-text-decorations-in-effect: none; -webkit-text-size-adjust: =
auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; "><span class=3D"Apple-style-span" =
style=3D"border-collapse: separate; color: rgb(0, 0, 0); font-family: =
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auto; -webkit-text-stroke-width: 0px; font-size: medium; "><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; "><br></div><div =
style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; =
-webkit-line-break: after-white-space; =
"><br><br></div></span></div></span></div></span></div></span>
</div>
<br><div><div>On Nov 27, 2016, at 4:45 PM, John Innis &lt;<a =
href=3D"mailto:jdinnis@gmail.com";>jdinnis@gmail.com</a>&gt; =
wrote:</div><br class=3D"Apple-interchange-newline"><blockquote =
type=3D"cite"><div dir=3D"ltr">Yes, truly an engineering question.&nbsp; =
It has been many years since I was in engineering school.&nbsp; But I =
know the answer to this one.&nbsp; You have not provided enough =
information to answer the question.&nbsp; We would need to know the wall =
thickness of the tank and type of aluminum.&nbsp; Measuring the wall =
thickness should be pretty easy, but figuring out the grad of aluminum =
may be very difficult.&nbsp; I suggest giving up on the engineering and =
resort to shade-tree mechanics.&nbsp; Use a piece of 3/4" plywood and =
cut a radius in it to match the tank, then bolt this between the upper =
arms of the 4x4 to make a cradle.&nbsp; Stack enough pieces of plywood =
together to match the width of the strap used on the truck.&nbsp; You =
know that method was sufficient under the dynamic load of a moving =
semi.&nbsp; Should be more than adequate for a stationary tank.&nbsp; It =
also has the added benefit of tying the 4x4's together at the point of =
load, so outward bending stresses will be reduced.&nbsp; Your 4x4 x ' =
should be fine as long as you use through bolts of adequate size to join =
the together in the middle and to bolt the ties at the base.&nbsp; To =
help insure the load on the 4x4's are minimized, you should cut the =
bottom ends to match the angle, so the sit flat on the floor.&nbsp; =
<br></div><div class=3D"gmail_extra"><br><div class=3D"gmail_quote">On =
Sun, Nov 27, 2016 at 2:48 PM, Matt <span dir=3D"ltr">&lt;<a =
href=3D"mailto:mbarre@juno.com"; =
target=3D"_blank">mbarre@juno.com</a>&gt;</span> wrote:<br><blockquote =
class=3D"gmail_quote" style=3D"margin: 0px 0px 0px 0.8ex; =
border-left-width: 1px; border-left-color: rgb(204, 204, 204); =
border-left-style: solid; padding-left: 1ex; position: static; z-index: =
auto; "><div>I hope you all had a great Thanksgiving and have plenty to =
be thankful for!</div>
<div>&nbsp;</div>
<div>I am adding diesel storage capacity to my shop.</div>
<div>I got a good deal on an aluminum semitruck fuel tank ( 26" diameter =
&nbsp;68" long) and need to construct a stand for it.</div>
<div>These are normally secured on the truck with metal straps or =
bands.</div>
<div>&nbsp;</div>
<div>For my stand I am considering constructing large "X" from pressure =
treated 4x4 and resting the tank in the upper V.</div>
<div>I would tie them together with 2x4 s to keep them from =
cocking.&nbsp; I figure I would be safe with 3 Xs if any doubt, 4 to =
make sure.</div>
<div>&nbsp;</div>
<div>Question: &nbsp;If I went with only 2 supports and kept them out on =
the ends, would the bending moment (bowing) threaten the integrity of =
the tank?</div>
<div>150 gallons is about 1000#.&nbsp; Similarly, would the reduced =
"contact patch" of X mounts vice continuous straps threaten the tank =
walls?</div>
<div>&nbsp;</div>
<div>I am sure I could dig out my old <em>Statics</em> book and find the =
equation, but don't have a design bending limit for the tank.</div>
<div>I am anticipating that just 2 supports, especially out at the ends =
would be too risky.</div>
<div>&nbsp;</div>
<div>&nbsp;</div>
<div>Thanks for your thoughts,</div>
<div>Matt in GA</div>
<div>&nbsp;</div>
<div>&nbsp;</div>
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