EA versus EAP

[Anonymous]

Hi,

I know that there is a difference in properties between EA and EAP, and that for EA you get the following warning;

This is fine for pure bending, but for bending + compression it it unconservative, as the phiMr, phiMi are calculated using a higher value of phiNc than is available. 

Is there a way that angle sections can have the lowest value of I, S, Z assigned to them to calculate member capacity in combined actions?

Tony

[Artur.Kosakowski]

Angles with no P in their names have got their properties calculated in axes that are parallel to their arms whereas angles with  in their names in their principal ones. In most cases you should use the P ones unless the boundary conditions 'force' the angle to deform 'vertically' or 'horizontally' (e.g. short post or diagonal in compound/truss type column).

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[Anonymous]

Hi Artur,

Yes I understand the difference between the two types, and to a certain extent agree with your comments.  However I just though that when an EA buckles in compression it may (most likely) will buckle about the weakest axis, which would be driven by the EAP values (i.e Iz, rz etc).  

Thanks anyway for the clarification

Tony

[Artur.Kosakowski · Accepted solution]

EA sections are intended to be used only when this cannot happen e.g. angle welded  under a thick steel plate. Otherwise you should use EAPs instead. In other words they are intended to be used for bending with 'forced' direction of the deformation rather than for compression.