D1.A.4 Built-in Steel Section Library
Most AISC steel shapes are available in the standard section database. The following sections describe specification of steel sections from the AISC structural product tables.
Wide Flanges (W shapes)
All wide flange sections as listed in AISC are available the way they are written, e.g., W10X49, W21X50, etc.
20 TO 30 TABLE ST W10X49 33 36 TABLE ST W18X86
C, MC, S, M, HP Shapes
The above shapes are available as listed in the AISC manual without decimal points. For example, C8X11.5 will be input as C8X11 and S15X42.9 will be input as S15X42, omitting the fractional portion of the weight past the decimal.
10 TO 20 BY 2 TABLE ST C15X40 1 2 TABLE ST MC8X20
Double Channels
Back-to-back double channels, with or without spacing between them, are available. The letter D in front of the section name will specify a double channel.
21 22 24 TABLE D MC9X25 55 TO 60 TABLE D C8X18
Front-to-front channel steel sections can be defined by using the FR (Double Channel – Front to Front) option and any spacing required between the channels are specified with the SP designation.
61 62 TABLE FR C4X5 SP 0.5
Angles
Angle specifications in STAAD.Pro are different from those in the AISC manual. The following example illustrates angle specifications.
Similarly, L505010 = L 5 x 5 x 5/8 and L904016 = L 9 x 4 x 1
At present, there are two ways to define the local y and z-axes for an angle section. To make the transition from the AISC Manual to the program data easy, the standard section for an angle is specified:
51 52 53 TABLE ST L40356
This specification has the local z-axis (i.e., the minor axis) corresponding to the Z-Z axis specified in the steel tables. Many engineers are familiar with a convention used by some other programs in which the local y-axis is the minor axis. STAAD.Pro provides for this convention by accepting the command:
54 55 56 TABLE RA L40356
Double Angles
Short leg back to back or long leg back to back double angles can be specified by inputting the word SD or LD, respectively, in front of the angle size. In case of an equal angle either LD or SD will serve the purpose.
14 TO 20 TABLE LD L35304 SP 0.5
Long leg back to back L3-1/2x3x1/4 with 0.5 space.
23 27 TABLE SD L904012
Short leg back to back L 9x4x3/4
Tees
Tees are not input by their actual names, as they are listed in the AISC manual, but instead by designating the beam shapes (W and S) from which they are cut. For example
1 2 5 8 TABLE T W8X24
Tee cut from W8x24, or a TW4x12.
Pipes
Two types of specifications can be used for pipe sections. Pipe sections listed in the AISC manual can be specified as follows.
5 TO 10 TABLE ST PIPX20
Where the strength spec is one of the following:
General pipe sections may be input by their outer and inner diameters. For example,
1 TO 9 TABLE ST PIPE 0D 2.0 ID 1.875
Indicates a pipe with an outer diameter of 2.0 and inner diameter of 1.875 in current input units.
Round HSS
Round hollow structural sections listed in the AISC manual can be specified as follows.
5 TO 10 HSS16X0.438 11 TO 12 HSS14X0.5_A1085
Indicates members 5 through 10 as 16" outer diameter and a nominal wall thickness of 7/16" (0.4375"). Members 11 and 12 have a 14" outer diameter and a 1/2" nominal wall thickness and use A1085 grade material.
- AISC codes require that the design of HSS sections use section properties calculated based on a reduced wall thickness. The STAAD.Pro database values incorporated a design thickness of 0.93× the nominal thickness.
- HSS sections using A1085 grade material per the AISC 360-16 and 360-10 codes are designed using section properties with the full nominal wall thickness. Thus, a separate set of tables is available to specify this material grade as these use different section properties.
Tubes
Two types of specifications can be used for tube sections. Tube sections from the AISC tables can be specified as follows.
5 TO 10 TABLE ST TUB120808
General tube sections may be input by their dimensions (height, width, and thickness) as follows.
6 TABLE ST TUBE DT 8.0 WT 6.0 TH 0.5
Indicates a tube that has a height of 8, a width of 6, and a wall thickness of 0.5 in the current input units.
Rectangular HSS
Rectangular hollow structural sections listed in the AISC manual can be specified as follows.
5 TO 10 HSST14X10X0.313 11 TO 12 HSST6X3X0.375_A1085
Indicates members 5 through 10 as a 14" x 10" tube with a nominal wall thickness of 5/16" (0.3125"). Members 11 and 12 are a 6" x 3" tube with a 3/8" nominal wall thickness and use A1085 grade material.
