AISC Table 3-23

[monty011]

Was curious about case #2 in the shear/moment/deflection tables on page 3-23. They have the max moment listed as .5774*l in the figure, but in the list next to the figure they have 1/sqrt(3)*l = .557*l. Shouldn't the .557 be .577?

Anybody else notice this in their copy? It wasn't listed on the errata of the 14th edition of any printing. Just wondering if this is something I should correct, or maybe i'm missing something.

 

[JoshPlumSE]

The 15th edition corrects this. They are now listed as 0.557*L and 0.5574*L.

Also note that this is the LOCATION of the maximum moment and zero shear.

 

[monty011]

Good to see they fixed it in the newer editions. Not sure why they couldn't have introduced it on their errata for the 14th.

 

[nutte]

If that's what the 15th edition says, it now has 2 errors. 0.5774*L is the correct value. Take the equation for Vx, solve it for x when V is zero, and you get L/sqrt 3. The error first showed up in the 13th edition manual. It was right in the manuals before that.

 

[monty011]

Yeah, I think he got mixed up with the numbers and meant the figure shows .5774*L and the list shows .577*L. At least I hope so for the 15th ed. I've marked up my 14th ed. manual to avoid any head scratching.

You'd think that would be some low hanging fruit for the AISC errata team. Considering they have 1/sqrt(3)*L right next to it.

 

[JoshPlumSE]

I almost responded how easy it would be to calculate it from the Vx formula. But, got lazy! Nutte's correct... the 16th edition has this wrong in two spots now.

That's gotta be just a little embarrassing to the good folks over at AISC. Not the typo itself. Those things happen with a manual that has so much material. The embarrassing part is messing up the correction.

 

[monty011]

Haha...oops! I'll just roll on with my penciled in 14th edition!

 

[TehMightyEngineer]

Interesting, the 13th edition has it correct. Gotta update eventually though, Maine finally adopted the 2015 IBC earlier this year.

Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/

 

[nutte]

TehMightyEngineer, what printing is your 13th edition? My 13th edition, 2nd printing, shows it incorrectly.

 

[TehMightyEngineer]

2nd edition. Oh, I take it back, the 13th edition also has it incorrect. I'm going to blame my inability to read on being very sick this week.

Ian Riley, PE, SE
Professional Engineer (ME, NH, MA) Structural Engineer (IL)
American Concrete Industries

https://www.facebook.com/AmericanConcrete/