This document discusses compression members, which include columns, struts, stanchions, and posts. Common cross sections used for compression members are single and double angles, channels, I-sections, rods, composite sections, and tube sections. Compression members can fail due to crushing or buckling. Key terms in the design of compression members are effective length, slenderness ratio, and economical cross section. The document provides examples of calculating the effective length and design compressive strength of a column.

1. COMPRESSION MEMBERS AS COLUMN
• Column, top chords of trusses, diagonals and
bracing members are all examples of compression
members

2. VARIOUS TERMS USED FOR
COMPRESSION MEMBER
• Strut : it is compression member of truss
• Column: it is compression member of buildings
• Stanchion: it is a built-up column with heavy
loads.
• Post: this term indicate compression member of
wooden structure.
• Boom: compression member of crane

3. • Common section used as Compression members
member
Single & Double Angles
Channel I-Section
(Joist / Beam)
Rod
Composite section
Tube Section
Hollow Section

4. • Modes of failure of Compression member
Crushing failure Buckling failure

5. Terms used in design of compression member
• Effective length (KL)
• Slenderness Ratio (𝜆𝑒𝑓𝑓)
• Economical Cross section

6. • Effective
length of
Column
(KL):
• The effective
length, KL, is
calculated from
the actual length
(L) of the
member,
considering the
rotational and
relative
translational
boundary
conditions at the
ends

7. • Maximum slenderness ratio (Stiffness Requirement)

8. Economical Cross section

9. Limit State Design Concepts
• Design compressive strength of a member or section (Pd) for MS
Flat
• Pd = Ae × fcd {Cl. 7.1.1 pg34}
Ae = Effective sectional area
fcd = Design stress in axial compression

10. Buckling class of cross sections

15. • Length = 6m
• ISHB 350 @661.2 N/m
• Cover plate 350x20mm
• The lower end of
column is restrained
against rotation and
translation upper end is
hinged.
• Calculate design
compressive strength