Collector / Drag Strut

When a shear wall does not extend the full length of a diaphragm, a collector must span from the wall end to the edges of the diaphragm to gather the forces that cannot be directly transferred. Collectors must be designed for both tension and compression forces, and their connections to the diaphragm and to the vertical resisting element must be detailed for the full collector force. In wood-frame construction, collectors are typically doubled top plates with metal connector straps; in steel-frame construction, beams act as collectors with moment or shear connections. Collector design is often one of the most demanding aspects of seismic detailing for irregular or large diaphragm buildings.