Missing Compression properties of ASTM 572 Gr 50 Structural I-beams

[ninix]

All,

Upon reviewing the property cards for a Gantry analysis I was interested to see that the compression properties for the I-beam material were assumed to be the same as the tensile properties (i.e. not specified). Searching MatWeb for the material properties yielded many results such as for ASTM A36 which has compression yield properties 61% of tensile yield. Since modelling of the structure will entail buckling analysis I am wondering how this issue is normally addressed by structural steel engineering, or if it is addressed in the factor of safety calculation?

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[dougantholz]

Gr 50 structural steel is typically ASTM A572 Gr 50 or ASTM A992.
For compression capacity you should look at AISC 360-05 which gives you the equations for plastic yielding, Euler Buckling and for intermediate elastic buckling curves. Look at AISC.org for a free download under the epubs tab for specifications. For crane columns you need to also look at combined loading sections for bending plus compression.