CIVIL ENGINEERING FORMULAS

COLUMN FORMULAS 89

Nomenclature for formulas Eqs. (3.4) through (3.12):

Qallowable load, lb

Pultimate load, lb

Asection area of column, sq in

Llength of column, in

rleast radium of gyration of column section, in

Suultimate strength, psi

Syyield point or yield strength of material, psi

Emodulus of elasticity of material, psi

mfactor of safety

(L/r)critical slenderness ratio

For columns of cast iron that are hollow, round, with flat ends, used in
buildings:

(3.4)

(3.5)

(3.6)

(3.7)

Min diameter 6 in; min thickness 1/2 in

(3.8)

For structural aluminum columns with the following specifications:

used in nonwelded building structures in structural shapes or in fabricated form
with partial constraint:

(3.9)

(3.10)

L

r

10  67

Q

A

20,400 135

L

r

L

r

 10

Q

A

19,000

6061 T6 6062 T6

sy35,000

su38,000

E10,000,000

P

A

34,000 88

L

r

Max

L

r

 70

Q

A

 9000  40

L

r

Max

Q

A

10,000; max

L

r

 100

Q

A

12,000 60

L

r