ABSTRACT
When direct or conventional outrigger walls or trusses are not acceptable for the building due to space limitations or a column layout which is not aligned with the core walls, an indirect, “virtual” outrigger or belt truss system may be used. Behavior of the exterior columns is tied to behavior of the core through stiff belts and strong, stiff floor diaphragms at upper and lower levels of each belt. This approach eliminates complicated outrigger connections at columns and at the core. It minimizes concerns about inadvertent load transfers between core and perimeter from differential shortening. Alternatively, a belt truss can be used together with direct, conventional outriggers to engage more, smaller columns rather than requiring fewer, larger mega columns. This results in more uniform perimeter column sizes where desired.
