5. (20 pts.) An office building 80 ft. tall has a bay size of 4d to support load
ID: 2312245 • Letter: 5
Question
5. (20 pts.) An office building 80 ft. tall has a bay size of 4d to support loads shown below in addition to the as a bay Size of 40 ft. (into the paper). The structure is designed floo KLx- KLy 16 ft. Fy 50 ksi Fy 50 kside flange mee sab weight of the floor and roof. Make a preliminary ize wide flange member for an interior column at grou Dead Load 40 psf 80 psf Live Load 20 psf 50 psf Roof Floor All floor slabs are 6 inch thick concrete slabs. The roof slab is 4 inches thick. 4 inch thick concrete slab 6 inch thick concrete slab 16 ft. 36 ft. 30 ft.Explanation / Answer
Tributary area of interior column from each floor= (30/2+ 36/2)*(40/2+40/2) = 1320 sq ft
self weight of roof slab= (4/12)*150=50psf
self weight of floor slab = (6/12)*150=75 psf
dead load from roof=40psf
dead load from each floor=80 psf
live load from roof=20 psf
live load from floor=50 psf
Total dead load on lowermost column = (50+4*75 + 40+ 4*80)*1320/1000=937.2 kips
Total live load on lowermost column = (20+4*50)*1320/1000=290.4 kips
Factored load = 1.2D+1.6L=1.2*937.2+1.6*290.4=1589.28 kips
The lightest W14 column that has compression capacity greater than 1589.28 kips for an effective length of 16 ft is W14x145
Therefore, W14x145 is the rewuired column size