AISC Library


Section 1. Introduction

The AISC Section Properties database (aiscrev9.dbf) file contains the section properties as described in the AISC manuals. The database file has 3 fields. The first field contains the name of the section (see Section 3) and has a width of 30 characters. The second field (width: 12) describes the property that is assigned to this name. Section 2 describes the symbols used in the second field. The third field (width: 50) contains the value of this property.

There are five general types of sections contained in the file:

 

Section 2. Variable Explanations

All dimensions are in inches and kips. These variables are taken from the AISC manuals. These values will NOT be scaled to the unit system of your model if you are using a unit other than inch for length or pound for force.

A: Area
BF: Width of flange
BTF: "bf/2tf", the ratio of the flange width to twice the flange thickness
CW: Cw, warping constant
D: Depth, actual
DAF: "d/Af", the ratio of the depth to the compression flange area
DI: Inner diameter of pipe
DN: Nominal depth. Nominal Diameter in case of pipe sections (P, PX, PXX)
DSG: Shape designation, i.e. "W" or "C"
DTW: "d/tw", the ratio of the depth to the web thickness
EO: "eo", distance from outside face of web to shear center
FYP: "Fy ' ", the theoretical maximum yield stress based on the width-thickness ratio of 1/2 the unstiffened compression flange, beyond which a particular shape is not compact. (Specified as 0 if greater than 65 ksi)
FYPPPA: "Fy ''' "(ASD), the theoretical maximum yield stress based on the depth-thickness ratio of the web below which a particular shape may be considered compact for any condition of combined bending and axial stresses. (Specified as 0 if greater than 65 ksi)
FYPPPL: "Fy ''' " (LRFD), See above.
H: "H", flexural constant LRFD Formula (A-E3-9)
H38: "H", flexural constant, double angles 3/8" back to back
H34: "H", flexural constant, double angles 3/4" back to back
HL: Horizontal leg or side dimension
HTW: "hc/tw", ratio of assumed web depth for stability to thickness of web
JSHP: JUMBO SHAPE ("J"), See the note at the end of the variable list.
NT: Tensile type number per ASTM A6
OD: Outer diameter of pipe
QF: "Qf", statical moment at point in flange
QW: "Qw", statical moment at mid-depth
RA: Minimum fillet radius, detailing value (in.); flange toe value for M, S, C and MC shapes
RI: Minimum fillet radius, design
RO: "ro", shear center coordinate
RO38: "ro", double angles 3/8" back to back
RO34: "ro", double angles 3/4" back to back
RT: The radius of gyration of a section comprising the compression flange plus 1/3 of the compression web area, taken about an axis in the plane of the web
RX: "rx", radius of gyration about axis XX
RY: "ry", radius of gyration about axis YY
RY38: "ry", double angles 3/8" back to back
RY34: "ry", double angles 3/4" back to back
RZ: "rz", radius of gyration about principal axis
SX: "Sx", elastic section modulus about axis XX
SY: "Sy", elastic section modulus about axis YY
SW: "Sw", warping statical moment
T: Thickness of leg or wall
TF: Thickness of flange
TW: Thickness of web
VL: Vertical leg or side dimension
WGT: Nominal weight
WNO: "Wno", normalized warping function
XB: "x", centroid of section in X direction from outer web
XI: "Ix", moment of inertia about axis XX
XJ: "J", torsional constant
XK: "k", distance from outer face of flange to web toe fillet of rolled shape
X1: "X1", beam buckling factor LRFD Formula (F1-8)
X2: "X2", beam buckling factor LRFD Formula (F1-9)
YB: "y", centroid of section in Y direction from outer top flange face
YI: "Iy", moment of inertia about axis YY
ZX: "Zx", plastic modulus about axis XX
ZY: "Zy", plastic modulus about axis YY
NOTE: Type 4 and Type 5 shapes are generally contemplated for application as columns or compression components. When used in other applications (e.g. trusses) and when thermal cutting or welding is required, special material specification and fabrication procedures apply to minimize the possibility of cracking (see June 1, 1989 ASD Specification Sects. A3.1, J1.11 and M2.2 and corresponding Commentary sections).

 

Section 3. Section Notation

Note:  All the records in the AISC .dbf files are locked for the cross -sectional libraries (i.e., the cross-sectional library cannot change any records in case you want to change the values). However, this does not apply to any library created through the cross-sectional libraries.

 

Section 4. Unsymmetrical Sections

The AISC section properties database includes the shear center and center of gravity locations for unsymmetrical sections such as angles and channels. The current linear beam element does not include twisting due to loadings which are offset from the shear center. Therefore, the Beam Design Editor use of the AISC properties ignores the shear center offset from the beam cross-section center of gravity. It is your responsibility to account for the effects of shear center offset from the center of gravity.

 

References

Manual of Steel Construction: Allowable Stress Design, 9th ed. (Chicago: American Institute of Steel Construction, Inc., 1989).

Manual of Steel Construction: Load and Resistance Factor Design, 1st ed. (Chicago: American Institute of Steel Construction, Inc.,1986).