B5.1 General
Chords, collectors, truss diaphragms, and their connections are part of the seismic force-resisting system and are subject to the requirements of Sections A3, D2.2, and D2.3. Diaphragms and chords shall be designed for the loads and load combinations in the applicable building code. Collectors shall be designed for the load combinations in the applicable building code, including overstrength. Diaphragm, chord, and collector forces resulting from transfer of lateral forces associated with horizontal offsets in the lateral force-resisting system shall use the load combinations in the applicable building code, including capacity-limited seismic forces associated with the transfer.
B5.2 Truss Diaphragms
When a truss is used as a diaphragm, all members of the truss and their connections shall be designed for forces calculated using the load combinations of the applicable building code, including overstrength.
Exception: The forces specified in this section need not be applied to truss diaphragms designed as a part of a three-dimensional system in which the seismic force-resisting system types consist of ordinary moment frames, ordinary concentrically braced frames, ordinary cantilever column systems, special cantilever column systems, or combinations thereof, and where the truss diagonal members conform to Sections F1.4b and F1.5 and the connections conform to Section F1.6.