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[Shop-talk] reinforcing roof joists

Subject: [Shop-talk] reinforcing roof joists
From: wmc_st at xxiii.com (Wayne)
Date: Tue, 20 Mar 2012 00:06:03 -0400
References: <20120318195754.9GYAQ.128731.root@cdptpa-web27-z01> <4F679305.9000803@xxiii.com> <4F67EDCE.8090401@tx.rr.com>
HuhHuh, yeah... it was 1972 and I was 6, and he was a non-degreed tool & 
die maker / motorhead.  I did learn how to use a slide-rule at one 
point.  But modern stuff will let you optimize the **** out of designs. 
  OTOH, I'm probably more impressed with the stuff pulled off without 
high tech tools (eg: SR-71, Hoover Dam, Nukes)

On 3/19/2012 10:39 PM, BJNoSHOV8 wrote:
> Finite element software? In college I was taught how to do those
> calculations by hand.
>
>> He "boxed in" the 6 or 8 trusses over the stall with plywood, and at
>> the top of each, cut a 2" radius semi-circle. Then put up a 4" OD
>> steel pipe spanning all of them. But he staggered the depth, so with
>> no load the pipe was sitting on the outer most plates. At the
>> calculated flex of the pipe under full load (1100 lbs??) it would
>> deflect and be roughly in contact with all the plates, hopefully
>> distributing the load fairly evenly across all the trusses.
>>
>> It was "seat of the pants" engineering, and I don't think anyone had
>> FEA software then, but it seemed sound.

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