for the framing plan shown for a two story building design c

for the framing plan shown for a two story building, design column numbers 4 and 5 using the following information. -floor loads:(dead load is 70 psf, live load is 50 psf) -roof loads(dead load is 63 psf, live load is 30 psf). design both columns for (a) LFRD and (b) ASD. select the lightest available W8\'s. hint** determine the influence area of the column then the load based on the area. once you have the loads you can design the columns.

57. Using the framing plan shown in Figure P5.57 (presented earlier as Figure 2.5), design the columns marked 4 and 5. This is the same structure used in Section 2.5, where load calculations with live load reductions were discussed. Those calculations can be reused here. Load case 2 for dead plus live load is to be con- sidered. The building is an office building with a nominal live load of 50 pounds per square foot (psf) and a calculated dead load of 70 psf. 4: Interior column D-2 regardless of deck span direction 5: Exterior column D-4 regardless of deck span direction Design for column length L=14 ft and K= 1.0 using (a) LRFD and (b) ASD 4 20 ft 20 ft 20 ft 40 ft 40 ft- 30 ft P5.57

Solution

column 4:

Tributary area of column 4=(30/2+30/2)*(20/2+20/2)=600 sq ft

roof dead load = 63 psf

roof live load = 30 psf

floor dead load=70 psf

floor live load = 50 psf

Given the structure is two storied

Total ASD load on Column = (63+30+70+50)*600/1000=127.8 kips

Total LRFD load on column = [1.2*(63+70) + 1.6*(30+50)]*600/1000=172.56 kips

The lightest W8 column that has ASD capacity greater than 127.8 kips for effective length of 14 ft is W8x31

The lightest W8 column that has LRFD capacity greater than 172.56 kips for effective length of 14ft is W8x31

column 5:

Tributary area of column 5=(30/2+30/2)*(20/2)=300 sq ft

roof dead load = 63 psf

roof live load = 30 psf

floor dead load=70 psf

floor live load = 50 psf

Given the structure is two storied

Total ASD load on Column = (63+30+70+50)*300/1000=63.9 kips

Total LRFD load on column = [1.2*(63+70) + 1.6*(30+50)]*300/1000=86.28 kips

The lightest W8 column that has ASD capacity greater than 63.9 kips for effective length of 14 ft is W8x24

The lightest W8 column that has LRFD capacity greater than 86.28 kips for effective length of 14ft is W8x24