2005 AISC Seminar Handout
2005 AISC Seminar Handout
(OP)
About a year ago, I attended an AISC seminar on the 2005 Specification. At this seminar, a booklet was handed out to participants. I'm reviewing the material for composite beams.
On sheet 4.16, Example 2, they calculate a Nominal Moment Strength of 1730 ft-kips. I cannot duplicate this result. I get 1381 ft-kips for this shape, by breaking it into 5 areas.
I wonder if anyone else has followed this example, and has verified AISC's result.
On sheet 4.16, Example 2, they calculate a Nominal Moment Strength of 1730 ft-kips. I cannot duplicate this result. I get 1381 ft-kips for this shape, by breaking it into 5 areas.
I wonder if anyone else has followed this example, and has verified AISC's result.





RE: 2005 AISC Seminar Handout
I re-did their numbers and I got 1723 ft-kips instead of their 1730. Not a big difference...I believe they just cheated a bit by using the top flange as the PNA instead of .209 inches below it.
Here's some of my numbers:
Area of beam below the PNA = 30.12 sq. in.
Area of flange above the PNA = 2.58 sq. in.
Force in slab = 1380 kips (.85 x 3 x 120 x 4.5)
Moment arm - slab NA to PNA = 2.459 in.
Force in top flange above the PNA = 129 kips (.209 x 12.34 x 50)
Moment arm - upper steel to PNA = .1045 in (.209/2)
Force in rest of beam below the PNA = 1506 kips (30.12 sq. in x 50)
Moment arm - lower steel to PNA = 11.47 in.
Mn = 1506(11.47") + 129(.1045") + 1380(2.459") = 20,681 in-kips
Mn = 20,681/12 = 1723 ft-kips.
RE: 2005 AISC Seminar Handout
Thank you. Your break down helped me find that I was using a web thickness of 0.17".