In general terms, the AISC requirements are based on the following principles:
1. The web plates are assumed to reach full tension yielding at an angle α. This angle is based on the wall geometry and the properties of the boundary elements.
2. The webs are designed to satisfy the shear demand determined from the applied loads.
3. To ensure that the webs can reach their full tensile strength, the required strengths of the connections to the boundary elements are based on the fully yielded strength of the web, using the expected tension yield stress, RyFy.
4. The boundary elements are designed to remain essentially elastic (with the exception of the anticipated plastic hinging at the ends of the HBE) when the web reaches its expected tensile strength at angle α. Because the webs are assumed to fully yield in tension, the required strengths of the boundary elements and their connections are based on strength of web and the plastic moment strength of HBE, combined with gravity loads.
5. The VBE–HBE moment ratio must meet the requirements specified in AISC Seismic for SMFs. This requirement is included to provide columns that are strong enough to force ﬂexural yielding in beams in multiple levels of the frame, thereby achieving a higher level of energy dissipation.
6. The width-thickness ratios of the boundary elements must meet the same requirement as SMF. This requirement recognizes the fact that significant frame action occurs in the system and ensures that the moments are compact enough to undergo significant inelastic deformation.
7. For the same reason, HBE have lateral bracing requirements similar to the beams in SMF.
8. The connections of the HBE to the VBE are expected to form plastic hinges, but they are not the intended source of energy dissipation. The SPSW is not expected to undergo as much drift as an SMF; therefore, the requirements of an SMF moment connection are not necessary. Instead, the expected performance is that of an ordinary moment frame connection.
9. The stiffness of the VBE is critical for achieving uniform tensile yielding in the entire web. Therefore, the VBE is required to have a minimum ﬂexural stiffness.
10. The panel zone requirements for the VBE at the top and base HBE of the SPSW are the same as those for SMF.