A Using the column design tables Table 47 select the lightes

A. Using the column design tables (Table 4-7), select the lightest WT shape of A992 steel for the following conditions, stating which axis controls the design:

WT7x, Pu = 150 kips, (KL)x = (KL)y = 18 ft.

B. Using the column design tables (Tables 4-8 to 4-10), select the lightest double angle shape of A36 steel for the following conditions, stating which axis controls the design:

2L3 (equal legs), Pu = 60 kips, (KL)x = (KL)y = 10 ft.

Solution

a)Axial load on column=150 kips

effective length of column about both axis = 18 ft

Per Table 4-7,The lightest WT7 that has compression capapcity greater than 150 kips is WT7x34

(KL)x controls the design

b) Axial load = 60 kips

effective length about both axis = 10 ft

The lightest 2L3x3 that has capapcity greater than 60 kips is 2L3x3x7/16

The axis that controls the design is (KL)x

b)