12.3.1 Beam Limitations
A number of different beam sizes were used in the frame tests, with the largest being W36 (W920) profiles and the smallest being W8 (W200) profiles. End-plate Yield-Links are qualified for use on smaller beams in the W8 (W200) to W12 (W310) range (or equivalent built-up sections). Because the capacity-based design procedure forces inelastic behavior into the connection rather than the beam, in general, the width-to-thickness requirements of the 2022 AISC Specification (AISC, 2022b) apply. However, because the connection does rely on the beam flange and web to form part of the buckling restraint assembly for the yielding portion of the Link, the beam flange thickness is required to be checked according to the requirements in Section 12.9, Step 10, and also have a minimum thickness of 0.40 in. (10 mm). Furthermore, the width-to-thickness value cannot exceed in AISC Specification Table B4.1a. Additionally, the capacity-based design procedure and connection performance (no plastic hinging in the beam) allows the beam stability bracing to be designed in accordance with the AISC Specification. The protected zone encompasses the shear connection and yielding portions of the connection, specifically the Yield-Links, and elements of the connection in contact with both.
12.3.2 Column Limitations
A number of different column sizes were used in the frame tests, with the largest being W36 (W920) profiles and the smallest being W6 (W150) profiles. Because only strong-axis connections were tested, beams are required to connect to column flanges. Where frames are detailed to create plastic hinging at the column base, the width-to-thickness requirements for highly ductile members apply in the first story.
Otherwise, the requirements of the AISC Specification apply. Column lateral bracing requirements in the 2022 AISC Seismic Provisions (AISC, 2022a) are to be satisfied. An exception is provided to allow bracing the column at the level of the top flange of the beam only if additional limits are placed on the column flexural design strength provisions of the AISC Specification to ensure the columns remain elastic outside the panel zones. The limits are noted in Step 13.2 of the Section 12.9 Design Procedure requirements.
12.3.3 Bolting Limitations
The connection testing specifically prequalified a number of bolts in the connection to be installed snug-tight. These include the Link flange-to-column flange bolts, end plate-to-column flange bolts, and the shear-plate bolts. These same bolts may also be installed pretensioned if desired. The buckling restraint plate bolts are required to be installed only snug-tight. The Link stem-to-beam bolts are required to be installed pretensioned to prevent slip that would occur under design loads. In the prequalification testing, slip would typically start between 2 to 3% interstory drift, at which point the bolts went into bearing. No special preparation of either the Links or the beam flange surfaces in the test frames was done. The only prequalification requirement is that faying surfaces not be painted.