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SWL (safe working load) vs. factored load

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JohnRwals

Structural
Joined
Jul 8, 2020
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155
Location
US
Hi!

I wonder how I can compare factored load with safe working load.
I got barrier cable design with vehicle impact load in the precast concrete parking structure.
When I try to select ferrule inserts, their capacity is given with SWL.
Let's say insert will take factored load 13 kips and insert capacity is SWL=6 kips with safety factor=3.
Can I use this insert?
How can I compare these two loads?

JRW
 
I would think Fn = 3*6 = 18 kips, and the strength reduction factor is 0.9 (say), thus ØFn = 18*0.9 = 16.2 kips > Fu = 13 kips.
 
I would just use the SWL and compare against ASD loading. Unless the manufacturer provides guidance for converting the SWL to an ultimate load I caution against assuming phi = 0.9.
 
Yes, depending on the nature of the stress, the load reduction factor can vary.
 
Using AISC Omega/Phi factors as a guide....

Phi____ Omega
1.0____ 1.5
0.9____ 1.67
0.75___ 2.0
0.65___ 2.31

So, for a FS 3, I'd be looking at a phi of around 0.5 (ish).

Really, you should be doing what driftLimiter proposes - transforming your ultimate load to a service load.

Please note that is a "v" (as in Violin) not a "y".
 
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