Hi I need help on my HW problem steel design course ASAP . A column is subjected
ID: 1710873 • Letter: H
Question
Hi
I need help on my HW problem steel design course ASAP .
A column is subjected to the following loads. Dead load. D = 30 kips, Roof live load, L_r = 25 kips, Snow load, S = 30 kips, Earthquake Load, E = 70 kips (download) or = 50 kips (upward), and a Wind load, W= 50 kips (download) or = 60 kips (upward). If LRFD design is used, determine the factored load (required strength) to be used in the design of the column, (compression and tension, if appropriate) State load combination number(s). Box your answers.Explanation / Answer
dead load = D = 30 kips
Roof live load =Lr =25 kips
snow load =S= 30 kips
Earthquake load = E=+70 kips, - 50 kips
Wind load = W=+ 50kips, -60 kips
The ASCE 7-10 load combinations that we should be considering are:
For maximum compression:
1.2D+1.6Lr + 0.5W = (1.2*30)+(1.6*25)+(0.5*50) = 101kips(compression)
1.2D+1.6S+0.5W = (1.2*30)+(1.6*30)+(0.5*50) = 109kips(compression)
1.2D+W+0.5Lr = (1.2*30)+50+(0.5*25)=98.5kips(compression)
1.2D+W+0.5S = (1.2*30)+50+(0.5*30)=101kips(compression)
1.2D + E + 0.2S = (1.2*30)+70+(0.2*30)=112kips(compression)
Therefore maximum design compressive force = 112 kips
For maximum tension :
0.9D+W = (0.9*30)-60 = -33kips = 33kips(tension)
0.9D+E = (0.9*30)-50 = -23kips = 23 kips(tension)
Therefore maximum design tension force = 33 kips