Question

Select the lightest angular to support a live load LL=60 Kips and a dead load DL= 30 Kips. The angular will be connected to a gusset plate through bolts. Use at least three bolts in one line and 2 in, as the distance between bolts in the load direction. Use A992 Gr 50. The length of the angular is 24 ft. (ignore block shear) Angular >1 Plate

assume 7/8

Answer 1

For A992 Gr. 50 steel, Fys 50 ksi, fu = 65 ksi Dead load a po = 30 kips Live load ap = 60 kips Length of the member a 24 ff Diameter of single line both = d = 1/2 in. LRED factored load = Pu = 1.2 Ppt 16P 11 132 a 1.2 x 30 + 1.6x60 = 132 kips L. Required gross orrea a Pul Ag 0.9 Fy = 2.93 ign 0.9 x 50 Required effective area = he = Pu 0.75 Fu 132 = 2.71 igor 0.75x65 The minimum padius of gyration should be at least 248 12 = 0.96 in 300 300 For bolked connection, effective area of the section Aes Ans. U u= Area reduction factor Net area of section Ang = Ag-t(dot) t = thickness of the section.

3 with Aaa Try L 5x5x2 with Aga 3.61 in smin=0.99 in. Ang = Ag-t (do + 1/3) 3.61 - (3) = 3.235 inn For two or three fasteners in the direction of loading uso.6 Aes= Ansalu = 3.2 35 80.6=1.941 22.71 in Not ok Tony L 6*6 7 16 writer Ag = 5.06 in Pa 1.19 in 5:06. (***) Ans = = 4.62 in 2. ok 4.62*0.6 = 2.77 in 72.71 in Aes Lightest single angle L 6 X 6 X 7 16