7 3 points You are designing a 24 foot long simply supported

7. (3 points) You are designing a 24 foot long simply supported steel roof beam. From your analysis, you have found that the maximum moment is 124 ft-k and the maximum shear is 28 k. The top of the beam is fully braced because it is attached to the roof. The bottom chord is braced every 4 feet. Select a WF beam using the AISC beam tables posted on the course website.

Solution

I have come up with two beam sections:

1 : section based on 124 kip-ft of sagging moment

since the beam is fully braced at top, compression flange is continuously braced

the required section is W14x22

2: section based on 124 kip-ft of hogging moment

since the bottom flange is braced every 4 ft, the unbraced length = 4 ft

the required section is W14x22