10.3.1 Beam Limitations
Beams shall satisfy the following limitations:
- (1) Beams shall be rolled wide-flange or built-up I-shaped members conforming to the requirements of Section 2.3.
- (2) Beam depths shall be limited to the following beam shapes or their built-up equivalents: W30 (W760), W27 (W690), W24 (W610), W21 (W530), and W18 (W460).
- (3) Beam flange thickness shall be limited to a maximum of 1 in. (25 mm).
- (4) Beam flange width shall be limited to a maximum of 12 in. (300 mm).
- (5) The clear span-to-depth ratio of the beam shall be limited as follows:
- (a) For SMF systems, 7 or greater.
- (b) For IMF systems, 5 or greater.
- (6) Width-to-thickness ratios for beam flanges and webs shall conform to the limits of the AISC Seismic Provisions. The value of used to determine the width-to-thickness ratio of beams with RBS cutouts shall not be less than the flange width at the center two-thirds of the reduced section, provided that gravity loads do not shift the location of the plastic hinge a significant distance from the center of the reduced beam section.
- (7) Lateral bracing of beams shall conform to the applicable limits of the AISC Seismic Provisions.
Exception: For SMF and IMF systems, where the beam supports a concrete structural slab that is connected between the protected zones with welded shear connectors spaced at a maximum of 12 in. (300 mm) on center, supplemental top and bottom flange bracing at the expected hinge is not required.
- (8) For RBS connections, the protected zone consists of the portion of the connection assembly and beam between the column face and the farthest end of the reduced beam section. For beams without reduced beam sections, the protected zone consists of the portion of the connection assembly and beam extending from the column face to a distance from the outside face of the collar flange, where is the depth of the beam.
10.3.2 Column Limitations
Columns shall satisfy the following limitations:
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(1) Columns shall be square 16 in. (400 mm) HSS or square 16 in. (400 mm) built-up box sections permitted in Section 2.3.
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(2) There is no limit on column weight per foot.
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(3) Column wall thickness shall not be less than 3/8 in. (10 mm). Column wall thickness for HSS columns shall not be less than 3/8 in. (10 mm) nominal.
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(4) Width-to-thickness ratios for columns shall conform to the applicable limits for filled composite columns in the AISCE Seismic Provisions.
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(5) Lateral bracing of columns shall conform to the applicable limits in the AISC Seismic Provisions.
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(6) Columns shall be completely filled with structural concrete having unit weight not less than 110 lb/ft³ (1 800 kg/m³). Concrete shall have 28-day compressive strength not less than 3,000 psi (21 MPa).
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(7) Flanges and webs of built-up box columns shall be connected using PJP groove welds with a groove weld size not less than 3/4 of the thickness of the connected plates as shown in Figure 10.5.
10.3.3 Collar Limitations
Collars shall satisfy the following limitations:
- (1) Collar forgings shall conform to the requirements of Appendix B, Forging Requirements. Forged parts shall conform to the material requirements of ASTM A572/A572M Grade 50 (Grade 345).
- (2) Cast collar parts shall conform to the requirements of Appendix A, Casting Requirements. Cast parts shall conform to the requirements of ASTM A958/ A958M Grade SC8620, class 80/50.
- (3) Collar configuration and proportions shall conform to Section 10.8.
- (4) Collar flange bolt holes shall be 1/8 in. (3 mm) larger than the nominal bolt diameter. Bolt holes shall be drilled.
- (5) Collar corner bolt holes shall be 1/8 in. (3 mm) larger than the nominal bolt diameter. Bolt holes shall be drilled.
- (6) Material thickness, edge distance, end distance, and overall dimension shall have a tolerance of ±1/16 in. (2 mm).
- (7) Faying surfaces shall be machined and meet the requirements for Class A slip-critical surfaces as defined in the AISC Specification.