The default parameter values have been selected such that they are frequently used numbers for conventional design. Depending on the particular design requirements, some or all of these parameter values may be changed to exactly model the physical structure.

Notes

1. For the AISC 360 unified code, an angle is automatically checked for geometric axis bending (in addition to principal axis bending) provided one of the following conditions is met:

   1. The FLX parameter is set to 2 for that member. The section could be an equal or an unequal legged angle.
   2. The angle is equal-legged, has bending moment only about one of its geometric axes, and is not subjected to axial compression.

   The AXIS parameter is only used by the deprecated AISC 360-05 code checking method (CODE AISC UNIFIED OLD). If this code is used, then AXIS 1 specifies design based on principle axes, where AXIS 2 specifies design based on geometric axes.

2. Non-default values of CB must be re-entered before every subsequent CHECK CODE or SELECT command.
3. Top and Bottom represent the positive and negative side of the local Y axis (local Z axis if SET Z UP is used).
4. For a description of the deflection check parameters DFF, DJ1, DJ2 see the Notes section of D1.B.1.2 Design Parameters of this manual.
5. NSF is the Net Section Factor as used in most of the steel design codes in STAAD.Pro. It is defined as the Ratio of "Net cross section area" / "Gross section area" for tension member design. The default value is 1.0. For the AISC 360 code, it is described in section D.3.2.
6. SLF is the Shear Lag Factor, as used in Section D.3.3 of the AISC 360-05 code. This factor is used to determine the effective net area by multiplying this factor with net area of the cross section. Please refer to Table D3.1 of the 360 code for a list of acceptable SLF values. In STAAD.Pro, the default value for SLF is 1.0. The effective net area is used to determine the tensile strength for tensile rupture in the net section, as per equation D.2.2.
7. To summarize, the "Gross Area" (Ag) is multiplied by NSF to get the "Net Area" (An) of the section. The "Net Area" (An) is then multiplied by SLF to get the "Effective Net Area" (Ae) of the section.
8. For the design of a single angle for flexure, the parameter LX should be used to specify the value of the term "L" in equations F10-4a, F10-4b, F10-5 and F10-6 of AISC 360-05 and the term "Lb" in equations F10-4, F10-5, F10-6a, and F10-6b of AISC 360-10.

9. When BEAM is 1.0 (default), the design is performed at 13 evenly spaced points along the length of the beam, including start and end points (i.e., 1/12th points or at ends of 12 equal length segments).

   

   The default sections for design when BEAM 1.0 is used

   When BEAM is 0.0, the start and ends along with up to three locations specified in TR.41 Section Specification are designed.

10. For AISC 360-16, the material strength values are first taken from the SGR parameter if specified (and not zero). The specify values for each SGR value are given in the following table. If SGR has not been specified, then the values of the FYLD and FU parameters will be used if specified. If no design parameters have been specified for material strengths, then the values in the material definition are used. If no material definition has been assigned, then the STAAD.Pro default values of Fy = 36 ksi and Fu = 58 ksi are assumed.

    Table 2. SGR values and corresponding material strength values for AISC 360-16

    SGR	ASTM Grade	Fy (ksi)	Fu (ksi)
    1	A36	36	58
    2	A53GrB	35	60
    3	A500 Gr.B (HSS Rect)	46	58
    4	A500 Gr.B (HSS Round)	42	58
    5	A500 Gr.C (HSS Rect)	50	62
    6	A500 Gr.C (HSS Round)	46	62
    7	A501 Gr.A	36	58
    8	A501 Gr.B	50	70
    9	A529 Gr.50	50	100 65* (if thickness > 1.5 in)
    10	A529 Gr.55	55	100 70*(if thickness > 1.5 in)
    11	A709 Gr.36	36	58
    12	A1043 Gr.36	36	58
    13	A1043 Gr.50	50	65
    14	A572 Gr.42	42	60
    15	A572 Gr.50	50	65
    16	A572 Gr.55	55	70
    17	A572 Gr.60	60*(if thickness <= 2.0 in)	75*(if thickness <= 2.0 in)
    18	A572 Gr.65	65*(if thickness <= 2.0 in)	80*(if thickness <= 2.0 in)
    19	A618 Gr.Ia.Ib & II	50 46*(if thickness > 0.75 in)	70 67*(if thickness > 0.75 in)
    20	A618 Gr.III	50	65
    21	A709 Gr.50	50	65
    22	A709 Gr.50S	50	65
    23	A709 Gr.50W	50	70
    24	A913 Gr.50	50	65
    25	A913 Gr.60	60	75
    26	A913 Gr.65	65	80
    27	A913 Gr.70	70	90
    28	A992	50	65
    29	A588	50	70
    30	A847	50	70
    31	A1085	50	65

11. For AISC 360-16, single angle members in compression can be designed using a modified slenderness method provided a set of conditions are met for that member. It is left to the engineer to confirm that conditions E5.(1) through E5.(3) are met and to specify this for single angle member using the E5P parameter. Those conditions are:

    • 1) Members are loaded at the ends in compression through the same leg.
    • 2) Members are attached by welding or by connections with a minimum of two bolts.
    • 3) There are no intermediate transverse loads.

    If one or more of these conditions are not met, then the E5P 1 parameter value should be assigned to those members.

    Note: Conditions E5.(4) and E5.(5) are checked by the program:

    • 4) Slenderness ratio, L_c/r ≤ 200
    • 5) For unequal leg angles, the ratio of leg widths is < 1.7.
    The effective slenderness ratio method used for single angles also depends on if those angle members are:

    1. individual members or are web members of planar trusses (in which case, Cl. E5(a) applies - IMM 0)
    2. web members of box or space trusses (in which case, Cl. E5(b) applies - IMM 1)

    A message is issued if the E5P or IMM parameter is used with any section type other than a single angle.

    Note: The E5P and IMM parameters are only applicable to standard catalog or UPT angles which also are assigned as truss members.