][ STEEL STRUCTURES ][

STEEL COLUMNS
==============
DESIGN WITH TABULAR DATA:
==========================
need to know section first
pick-and-try method
stock sections
single-piece columns
AISC Manuals
1. Effective length (KL)
2. Allowable Column Loads
3. Fy = Steel Grade
4. Member Size

I-Shaped Columns
=============
Table 10.2  PA 321, 322
W
M 
AISC Manuals
1. Effective length (KL)
2. Allowable Column Loads
3. Fy = Steel Grade
4. Member Size
	depth
	weight

Example:
=======
A column is pinned at top and bottom 
and has a laterallly unsupported height of 20 ft.
Select a wide-flange shape for an axial load of 200 kips.

A. Given:
-----------
L = 20 ft
P = 200 kips

B. Asked:
------------
M shape
W shape

C. Graph
-----------
	V   P = 200 kips
	|     L = 20 ft

D. Solution:
--------------
1. K = 1.0
2. K L = 1 x 20 ft
	KL = 20 ft
3. Table 10.2  PA 321
4. KL = 20      vertical
5. Allowable Column Load = 200     horizontal
	found 221

E. Solution:
=========
Shape  
	W 12 x 53
	W 10 x 54
	W 8 x 67
	no M member will work

Pipe Columns 
==========
pipe can be
		seamless
		welded
Table 10.4 PA 324
1. Fy = Material Type
2. Effective Length (KL)
3. Nominal Diameter
	true diameter are 
	slightly larger
	Table 4.4 PA 177
	1" nom = 1.315" actual
4. Wall Thickness
5. Weight per foot
		extra strong
		double-extra strong



Tubular Columns
Tubular Columns
=============
	produced to exact dimensions
	not to nominal sizes

Tubes with seams
	hot rolled strips
	flash or resistance welded 	together

Seamless Tubing
	piercing
	cupping
	extrusion

Shapes
	round 
	square
	rectangular

Sizes:
	2 - 16 in. square
	3 x 2 - 20 x 12 in.
	3 x 3 for 4" wall
	various thicknesses
Tubing
	Fy = 46 ksi

Table 10.5 PA 325




 DOUBLE-ANGLE COMPRESSION MEMBER
DOUBLE-ANGLE COMPRESSION MEMBER
===================================
STRUTS:
				2 ANGLES attached
				at intervals to a plate
				|L
				plate 3/8" typical
3 Series:
	equal leg angles
	unequal leg angles
			with short legs
			back to back
	unequal leg angles
			with long legs
			back to back
The usual practice  is to assume
	K = 1.0
	smaller radius of gyration 
	governs
	Table 10.6 PA 328 329





Cold Formed C Members
cold formed steel 
	ASTM A 570
	42,000 psi for light structural members

annealed steel
	softer steel
	finishes


	
STEEL COLUMNS RELATED SITES

W Shapes

M Shapes

Pipe Columns

Tubular Columns

Double-Angle Compression Members

Cold Formed C


 
 









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College of

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The University of Oklahoma


©Dr. Gruenwald 1996, 1997