D1.A.9 Seismic Provision Checking per AISC 341
Additional parameters may be specified for member checking or design per AISC 360-05, 360-10, or 360-16 to perform seismic provision checks per the corresponding edition of AISC 341.
The SEISMIC parameter is used to specify seismic provision checks for members. For those members in the AISC 360-05 or 360-10 editions, the MTYP (member type), FRM (frame type), and BRC (bracing type) parameters are used to specify the structure and member details. For the AISC 360-16 edition, only the MTYP (member type) parameter is used to specify the member details. See D1.A.6 Design Parameters for details on the values used for these parameters.
Provisions Checked
The following checks are performed with the SEISMIC 1 parameter for the AISC 341-05/10 specifications:
- seismic classification of the member - the "worst case" classification is considered among all elements for the member. For
- required
flexural strength of the member -
- OMF - Mr = Mz (moment about major axis), per Sec. 11.8 of AISC 341-05 or Sec. E.1.4 of AISC 341-10
- IMF - Mr = Mu = RyZFy (LRFD) or = RyZFy/1.5 (ASD) per Sec. 10.8 of AISC 341-05 or Sec. D.1.2a of AISC 341-10
- SMF - Mr = Mu = RyZFy (LRFD) or = RyZFy/1.5 (ASD) per Sec. 9.8 of AISC 341-05 or Sec. D.1.2b of AISC 341-10
- required
bracing strength
- Relative bracing for beams - Pbr = 0.008MrCd/h0 per eq. A-6-5 of AISC 360 05/10
- Nodal bracing for beams - Pbr = 0.02MrCd/h0 per eq. A-6-7 of AISC 360 05/10
- Relative bracing for columns - Pbr = 0.004Pr per eq. A-6-1 of AISC 360 05/10
- Nodal bracing for columns - Pbr = 0.01Pr per eq. A-6-3 of AISC 360 05/10
- required
bracing stiffness: each of the following are multiplied by
1/ϕ for LRFD or by
Ω for ASD:
- Relative bracing for beams - βbr = 4MrCd/(Lbh0) per eq. A-6-6 of AISC 360 05/10
- Nodal bracing for beams - βbr = 10MrCd/(Lbh0) per eq. A-6-8 of AISC 360 05/10
- Relative bracing for columns - βbr = 2Pr/Lb per eq. A-6-2 of AISC 360 05/10
- Nodal bracing for columns - βbr = 8Pr/Lb per eq. A-6-4 of AISC 360 05/10
- required bracing spacing
Provisions Checked for AISC 341-16
The following checks are performed with the SEISMIC 1 parameter for the AISC 341-16 specification:
- Section seismic classification against ductility – the section is evaluated to be seismically compact or seismically non-compact for either highly or moderately ductile members (specified using the DUCT parameter)
- Required flexural strength of member checked per D1-1
- Stability bracings of
beam
- Maximum allowed spacing of bracings checked per D1-2
- Required strength of lateral beam bracing at panel type flange lateral bracing (A-6-5 of AISC 360-16), point type flange lateral bracing (A-6-7 of AISC 360-16), and special flange lateral bracing at plastic hinge locations (D1-4)
- Required strength of torsional bream bracing at point torsional bracing (A-6-9 of AISC 360-16), continuous torsional bracing, and special torsional bracing at plastic hinge locations (D1-5)
- Required stiffness of beam bracing at panel type flange lateral bracing and point type flange lateral bracing (A-6-6 of AISC 360-16)
- Required stiffness of torsional bracing at point torsional bracing (A-6-10 and A-6-11 of AISC 360-16) and continuous torsional bracing (A-6-13 of AISC 360-16)
- Special bracing at plastic hinge locations (D1-6)
- Stability bracings of column
- Stability bracing of beam-column
Output
The output for the AISC 341-05/10/16 checks follow the checks for AISC 360-05/10/16 for a member. No seismic provision checks are printed for TRACK 0 output. For TRACK 1 output, the seismic classification and the requirements are given. TRACK 2 adds the details of the classification limits.
Track 1 example for AISC 341-10:
|-----------------------------------------------------------------------| | SEISMIC PROVISION(AISC 341:10):- | | | | MOMENT FRAME TYPE: IMF | | | | SEISMIC CLASSIFICATION: FLANGE: Compact WEB: Non-Compact | | | | REQUIREMENTS:- VALUE CRITERIA | | EXPECTED FLEXURAL STRENGTH 5.05E+02 Sec. D.1.2a. | | BRACING STRENGTH 2.78E+00 Eq. A-6-5 | | BRACING STIFFNESS 2.67E+06 Eq. A-6-6 | | BRACING SPACING 1.36E+01 Sec. D.1.2a. | |-----------------------------------------------------------------------|
Track 2 example for AISC 341-10:
|-----------------------------------------------------------------------| | SEISMIC PROVISION(AISC 341:10):- | | | | MOMENT FRAME TYPE: IMF | | | | SEISMIC CLASSIFICATION: CLASS: l : l md: | | FLANGE: Compact 6.575 9.152 | | WEB: Compact 47.465 35.884 | | | | REQUIREMENTS:- VALUE CRITERIA | | EXPECTED FLEXURAL STRENGTH 5.05E+02 Sec. D.1.2a. | | BRACING STRENGTH 2.78E+00 Eq. A-6-5 | | BRACING STIFFNESS 2.67E+06 Eq. A-6-6 | | BRACING SPACING 1.36E+01 Sec. D.1.2a. | |-----------------------------------------------------------------------|
Track 2 example for AISC 341-16:
|-----------------------------------------------------------------------------| | CHECKS FOR 341-16 SEISMIC CRITERIA | |-----------------------------------------------------------------------------| | FLEXURAL STRENGTH X | | DEMAND CAPACITY RATIO REFERENCE L/C LOC | | -183.8 280.6 0.655 Eq.D1-1 4 17.50 | | | | Intermediate Results : | | Overstrength factor : Ry = 1.0000 TableA3.1 | | Allow. Brac Spc : Lb = 15.167 ft Eq.D1-2 | |-----------------------------------------------------------------------------| | FLEXURAL STRENGTH Y | | DEMAND CAPACITY RATIO REFERENCE L/C LOC | | 0.000 46.11 0.000 Eq.D1-1 4 0.00 | | | | Intermediate Results : | | Overstrength factor : Ry = 1.0000 TableA3.1 | | Allow. Brac Spc : Lb = 15.167 ft Eq.D1-2 | |-----------------------------------------------------------------------------|