Eccentrically Loaded Single Angles

[cdi12]

Table 4-12 (AISC Manual 13th) shows available axial strength for eccentrically loaded single angles.
For example: L4x4x1/4, Grade 36, KL=5ft, Pmax=13.4kips
while Table from Eng. Journal, Second Quarter 1991
(by Wayne Walker) shows Pmax=9.6 kips
Anybody knows why?

Thanks,

 

[Galambos]

i did some work for a paper with my former advisor that has been submitted to AISC on this very topic. we looked at three different design methods including empirical research, each of which gave drastically different results. specific boundary conditions have a big effect.

 

[WillisV]

cdi12 - the Tables you refer to in the 13th edition manual are based on a paper and load tables generated by Sakla (Engineering Journal, 3rd Quarter, 2001).

The method employed by Sakla is even more tedious (however also more correct and less conservative - hence the increase in strength) than that employed by Walker. Sakla's methods were also rooted in LRFD design. The ASD tables in the 13th edition manual are a soft conversation of the LRFD values (just take the LRFD value, divide by phi of 0.9, and divide by omega =1.67 to get the ASD values in the table).