Page 171 - Marine Structural Design
P. 171
Chapter 8 BucklingKoIlapse of Columns and Beam-columns 147
Figure 8.4 An Initially Curved Beam-Column Carrying Eccentrically
Applied Loads
8.2.3 Ultimate Strength of Beam-Columns
For practical design, a linear interaction for the ultimate strength of a beam-column under
combined axial force and bending is often expressed as:
P
+-
- Muq1 (8.34)
’ULT *ULT
where PuLT and MuLT are the ultimate strength of the beam-column under a single load
respectively. Based on Eq. (8.34), the maximum moment in a beam-column under combined
axial forces and symmetric bending moments M, , is given by:
(8.35)
Then, the ultimate strength interaction equation may be expressed as:
(8.36)
Determining the exact location of the maximum bending moment for beam-columns under
non-symmetric bending moments is not straightforward. Instead, M, is substituted by an
equivalent moment, MEQ = CUM,.
(8.37)
where (Galambos, 2000)
Cu =0.6-0.4-20.4 (8.38)
MB
M*
where MA and MB are end moments.
