Steel Construction Manual American Institute of Steel Construction Thirteenth Edition Part 1 Dimensions and Properties 1

Wide-flange (W) Shapes Most widely used section Two flanges held apart by a web Essentially parallel inner and outer flange surfaces Section designation Weight in pounds/per foot W 24 x 55 Nominal depth in full inches Nominal depths from 4-inch to 44 inch Weights available from 9 lb/ft to 800 lb/ft

Wide-flange (W) Shapes W 14 x 730 Actual depth is 22.4 inches W 14 x 90 Actual depth is 14 inches All shapes from W14 x 90 to W 14 x 730 have flat (T) part of web of 10 inches. All these shapes can be stacked on each other 5

Major axis Flange Web Weak axis Designation

Actual depth Cross-sectional area

Flange Properties WebThickness

End of fillet transition between web and flange Flat portion of web Spacing between rows of bolts in flange

Flange and web stability Moment of Inertia (I), elastic section modulus (S), radius of gyration (r), plastic section modulus (Z) for strong and weak axes Weight per foot Flange and web stability parameters

M-Shapes Not classified in ASTM 6 as W-, S- or HP- shapes Same properties (A, d, tw, bf, etc) as W- shapes Can have sloped inside flange or other features 11

American Standard (S) Shapes 16-2/3% slope on inner flange surface Relatively narrow flanges and thicker webs when compared to W shapes Section designation S24x121 Weight per foot Nominal depth Use is less common because of lower moment of inertia, tapered flanges and low lateral stiffness

Narrow flange Note: slope on inside of flange

Same properties as for W shapes 14

Channels Nominal depth is same as actual depth Section designation C15x50 Weight in pounds per foot Actual depth MC – Miscellaneous channel – Other than 2 on 12 slope on inner flange

Property for design Property for detailing Actual depth

Angles For a single angle major axes do not correspond to x and y axes Section designation Short leg length L6x4x3/4 Thickness of both legs Long leg length Equal leg and unequal leg angles available Angles are best used in pairs as LLBB (Long-leg- back-to-back) or SLBB (Short-leg-back-to-back).

Location of elastic centroid Location of plastic centroid X axis properties Designation

Minor (weak) axis for a single angle Y axis properties

Tees WT -, MT- and ST- are obtained by shearing or thermal-cut from parent shape of W, M and S respectively Two WT 22 x 131 can be made by cutting a W 44 x 262 Nominal depths and weights of a WT is exactly half of the parent shape Off-center cuts can be done but properties not listed in Manual Used for top and bottom chords of trusses and diagonal bracing in buildings 20

Stem, not web

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Hollow Structural Shapes Rectangular, Square or Round HSS Welded or Seamless Welded HSS made by welding sheet steel Seamless made by extrusion of solid round bars Outside longer dimension HSS 10 x 4 x 3/8 Wall thickness Section Designation Outside shorter dimension 23

Strong axis structural properties Outside Longer Dimension Strong axis structural properties Actual Wall Thickness Outside Shorter Dimension Design Wall Thickness = 0.93 x Actual Wall Thickness 24

Weak axis structural properties

Structural properties for strong and weak axes Equal outside dimensions

Nominal versus design thickness Diameter over design thickness

Nominal wall thickness Standard, x-strong and xx-strong designations

Double Angles 2L6x4x3/4 Major axes are now x and y X axis properties may be obtained from x axis properties of single angle Y axis properties depend on separation between backs angles and whether LLBB or SLBB 29

Long legs back-to-back Short legs back-to-back Radius of gyration for compression members Separation due to gusset plates

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Double Channels Designated as 2C or 2MC 2C15x50 Y axis properties depend on back-to-back separation X axis properties can be obtained from x axis properties of single channel 32

Y axis properties depend on back-to-back distance (gusset plate thicknesses) between individual channels

Suitable for Crane Girders Channel Moment of Inertia, Ixx W shape Weight

Nominal wall thickness

Preferred Specification Limited availability Steel Types

Plates > 8 inch width Bars < 8 inch width Thickness in inches