Interface of the direct analysis method and seismic design

The Direct Analysis Method (DM) is a new procedure to address stability requirements in steel framing systems. Because the DM has important benefits over conventional methods, it is expected that the DM will replace the conventional methods as the standard method for stability analysis and design. However, currently, the interface of the DM and seismic design requirements is not well established. Stability is an important design consideration both in the absence of earthquake loads when the system ductility demand at the ultimate strength level is minimal, and in the presence of earthquake loads when the design premise is to permit controlled inelastic deformation in the system and provide large ductility capacity. Nonetheless, previous studies of the DM have not examined in depth how the DM could address seismic effects. Therefore, a study was initiated to investigate the interface of the DM and seismic design requirements, as the first step to expand the application and benefits of the DM to seismic design. The objectives of the study are: (1) to clarify how the DM addresses seismic effects; (2) to evaluate how the DM including plastic analysis, termed "direct elastic-plastic hinge analysis, " addresses seismic effects; and (3) to identify research needs related to the interface of the DM and seismic design requirements. This paper describes a pilot study that partially addressesobjectives (1) and (2).