Six Minute #7

[Erin]

I worked through question #7 in Six Minute Solutions Structural. I got the wrong answer becuase I used the formaul from the index:

ymax=(5wL^4)/384EI

The formula listed in the solutions sections is

ymax=(.0069wL^4)/EI

Where does this come from?????

 

[Cavalier55]

I worked through question #7 in Six Minute Solutions Structural. I got the wrong answer becuase I used the formaul from the index:
ymax=(5wL^4)/384EI

The formula listed in the solutions sections is

ymax=(.0069wL^4)/EI

Where does this come from?????

Erin - If you look on page 3-224 of the AISC manual. You will find loading diagram 39. I believe this is a misprint from the solution which states 36. Any way, in diagram 39 which fits the condition in the problem, the maximum deflection is given as ymax=0.0069wL^4/EI, this max occurs at 0.446l from A or D. Therefore the maximum deflection occurs at the 1 and 3 span, but they are only asking for the 1st span. I hope this helps.

Robb

 

[Erin]

Erin - If you look on page 3-224 of the AISC manual. You will find loading diagram 39. I believe this is a misprint from the solution which states 36. Any way, in diagram 39 which fits the condition in the problem, the maximum deflection is given as ymax=0.0069wL^4/EI, this max occurs at 0.446l from A or D. Therefore the maximum deflection occurs at the 1 and 3 span, but they are only asking for the 1st span. I hope this helps.
Robb

Thamks! I should get that manual.

Erin

 

[Erin]

Looked through the AISC Manual (LRFD) and could not find a page 3-224 or a table 39. Do I have the wrong manual?

Erin

 

[Erin]

Found it in AISC 4-203 diagram 36. Thanks for the response.