bearing stress question

[picasa]

I thought that this will be a better place for this question and hence I am reposting my earlier question for a different forum. Sorry for sorta breaking the eng-tips laws.

Please take a look at AISC Manual of Steel construction - Allowable Stress Design (9th edition). Go to page 5-74 and look at equation J3-3. It basically tells me to use the smaller of the two values (Le*Fu/2d) and 1.2*Fu as the allowable bearing stress. Well if (Le*Fu/2d) is greater than 1.2*Fu, you are basically using 1.2*70000 = 84000 psi as the allowable bearing stress! Does that sound right? I think equation J8-1 on page 5-79 is the correct equation for the allowable bearing stress. Please advise. Am I making any mistake in reading equation J3-3?

 

[JAE]

picasa - Yes, 84,000 psi is correct - bearing rarely controls a design unless you use fairly thin plates.

Read the AISC commentaries on these sections on page 5-168 (for J3.7) and on page 5-171 (for J8) for a good summary of it all.