4.5 Frames Not Part of the Lateral-Force-Resisting System
This section deals with frames that were not designed to be part of the lateral-force-resisting system. These are basic structural frames of steel or concrete that are designed for gravity loads with shear walls, bracing or moment frames providing the resistance to lateral forces.
If the primary lateral-force-resisting system consists of concrete walls (infilled in steel frames or monolithic in concrete frames), the building shall be treated as a concrete shear wall building (Type 6) with the frame columns as boundary elements. If the walls are masonry infills, the frames shall be treated as steel or concrete frames with infill walls of masonry (Type 7 or 10). Buildings with steel braces shall be treated as braced frame systems (Type 4). The principal deficiency identified in this section is loss of vertical-load-carrying capacity due to excessive deformations.
The analysis must include the deformations imposed by the infill walls, and the consequences of the failure of such walls.
The steel or concrete frames form a complete vertical load-carrying system.
For conforming buildings, the evaluator may consider this condition as mitigated, and no calculations are necessary. Check the shear walls or braced frames, including the effects of all dead and live loads, and note that the R values for buildings without a complete vertical load-carrying space frame are different from those for complete frame buildings. For wall systems, the frame is considered incomplete if the beams end at the edge of a shear wall that has no boundary columns or, if there are such columns, the beams do not continue across in the plane of the wall. For chevron-braced frame systems, the frame is considered incomplete if the beam in the brace frame cannot carry the design dead and live loads without the presence of the braces.