AISC13th, Web crippling at Beam Ends question

[RobertEIT]

There is a conflicts in AISC-13th: on page 9-19, Web crippling at Beam Ends, at bottom table, for distance x>=d/2, only R3 is multiplied by 2, R4 does not apply factor 2. But on Table 9-4 from page 9-38 to 9-51, both R3 and R4 are to be multiplied by 2 when distance x>=d/2.

Table 9-4 conflicts with formulas on page 9-19.

Is table 9-4 wrong?

 

[JAE]

Robert - if you look at the actual formulae for R₃ and R₄ on page 9-18 of the manual - you can see that R4 is indeed 1/2 of that indicated in the specification for the second term of equation J10-4.

I think the equation shown at the bottom of page 9-19 is missing a couple of parentheses. If you look at section J10.3 it is obvious that equation J10-4 uses a 0.8 term on the whole vs. the other equations.

Probably should notify AISC about this - it isn't in the latest errata that I have for the manual.

 

[RobertEIT]

JAE:

Comparing formulas in 9-18 with formula J10-4. it seems R4 term in page 9-19 bottom formulas does miss a factor 2. Right?

 

[JAE]

Yes it looks like it to me.

As I said...if you add a parenthesis around everything but the 2 then it works ok.