CIVIL ENGINEERING FORMULAS

252 CHAPTER TEN

Emodulus of elasticity of material, psi

mfactor of safety

(L/r)critical slenderness ratio

(10.11)

SuggestedSy32,000; suggested m1.7

(10.12)

or

(10.13)

(10.14)

(10.15)

When the column ends are pinned, the following formulas apply:

(10.16)

(10.17)

(10.18)

(10.19)

For structural silicon steel with Su80,000 psi and Sy45,000 psi, using
structural shapes, or being fabricated with the ends riveted,

(10.20)

Q

A

20,0000.46

L

r

2

up to

L

r

 130

P

A

25,6000.566

L

r

2

up to

L

r

 140

P

A



Sy

1 0.25 sec

0.85L

2 r B

P

EA

Q

A



18,750

1 0.25 sec

0.875L

2 r B

1.76Q

EA 

for

L

r

140

Q

A

15,000

1

3 

L

r

2

up to

L

r

 140

Q

A



18,750

1 0.25 sec

0.75L

2 r B

1.76Q

EA

for

L

r

140

Q

A

15,000

1

4 

L

r

2

up to

L

r

 140

P

A

25,6000.425

L

r

2

up to

L

r

 160

P

A



Sy

1 0.25 sec

0.75L

(^2) B

P

EA

Q

A



Sy/m

1 0.25 sec

0.75L

2 r B

mQ

EA