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# GLB - Need help with radius GLB thrust calcs

• To: "Seaoc@Seaoc. Org" <seaoc(--nospam--at)seaoc.org>
• Subject: GLB - Need help with radius GLB thrust calcs
• From: "Dennis S. Wish" <wish(--nospam--at)cwia.com>
• Date: Sat, 4 Apr 1998 22:26:12 -0800

```This should be elementary, but I am having trouble getting my templates to
match the example in the AITC 4th edition Table 5.20.
I am simply trying to determin the Summary of Dead Load Moments taken at
each 10th point on the radius beam.
Unfortunately the AITC manual does not provide a sample of the Ms
calculation for dead loads. I can only assume it is the reaction times the
distance to the point the moment is being calculated minus the distributed
dead load times the arc length again times the distance to the center of the
arc length.

Ms = Rv*x-wdl*x^2/2

Unfortunately the moments I calculate differ from the book and by the time
you get to the tenth node, the difference is significant.

Has anyone worked through a curved GLB calc to determine the thrust in the
horizontal direction. If so, have you created a mathcad template or
spreadsheet that you would be willing to share.
I have created a spreadsheet to determine the x and y coordintates
corresponding with the central angle alpha sub n as indicated in Table 5.19
of the AITC manual.
At the very least this allows you to determine the physical characters of
any arch. If anyone is interested, I will provide my work. It uses MathCad
for the constant values and Excel for determining the physical location of
each point on the beam.

It's been too long since I've been out of school and I am getting frustrated
by too many assumptions.

Can anyone offer a hand that has been through this one?

Dennis S. Wish PE
La Quinta, California
wish(--nospam--at)cwia.com

ICQ# 6110557
http://wwp.mirabilis.com/6110557

"Science may have found a cure for most evils; but it has found no remedy
for the worst of them all - the apathy of human beings"  Helen Keller

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