Profile cross-sections use a numbering system called key points. Members use an equivalent point system called cardinal points. The numbering convention for cardinal points differs from key points, as described below.
Key Point Numbering Conventions
Key points are numbered consistently among all types of profile cross-sections without regard to the number of geometric elements. This assures consistent behavior in the software when changing cross-sections of an existing profile system. As a result, some points are coincident on some cross-sections. Key point numbering is based on an I-beam profile because it is the most complex shape. Numbering for other profiles is derived from the I-beam.
I-beam Includes rolled and built-up cross-sections. |
S-beam |
T Includes T and I-to-T. Midpoint is from top of flange. |
Fabricated T Midpoint is from bottom of flange. |
S-T Midpoint is from top of flange. |
Angle
Midpoint is from top of flange. |
Fabricated angles Midpoint is from top of flange. |
Midpoint is from bottom of flange. |
Channel |
S-channel |
Flat bar |
Bulb |
Pipe Includes pipe, tube, and round bar. |
Rectangular tube |
Half-round
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Cardinal Point Numbering Conventions
A cardinal point defines the location where the software displays a member cross-section. There are 15 cardinal points definable for a member cross-section symbol, but only one can be used at a time when the member is placed. Each cardinal point has a number and a name.
The local y-axis of the member and the center-of-gravity point of the section define load points 11 and 14. The local z-axis of the member and the center-of-gravity point of the section define load points 12 and 13. The location of points 10 (center-of-gravity) and 15 (shear center) depend on the section shape.
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