2.4.6 Demand on Parts and Portions of the Building
Parts and portions of structures and permanent nonstructural components and equipment supported by a structure and their attachments, as identified in the building evaluation procedures, shall be evaluated to verify that they are capable of resisting the seismic forces specified below. All attachments or appendages, including anchorages and required bracing, shall be evaluated for seismic forces. Nonrigid equipment, the structural failure of which would cause a life-safety hazard, also shall be evaluated.
Each element or component evaluated shall be capable of resisting a total lateral seismic force, Fp, where:
where:
Av = the velocity-related acceleration coefficient given in Figures 2.1 and 2.1a.
Cc = a coefficient given in Table 2.4.6.
Wc = the weight of the element or component.
The NPC of the building shall be determined using the procedures in Article 11.
SEISMIC COEFFICIENT, Cc
| Cc | ||
| Parts of structure | Walls: | |
| Unbraced (cantilevered parapets and walls) | 2.4 | |
| Other exterior walls at and above the ground floor | 0.9 | |
| All interior bearing and nonbearing walls and partitions | 0.9 | |
| Masonry or concrete fences over 6 feet high | 0.9 | |
| Penthouse (except where framed by an extension of the building frame) | 0.9 | |
| Connections for prefabricated structural elements other than walls with force applied at the center of gravity | 0.9 | |
| Nonstructural components | Exterior and interior ornamentations and appendages | 2.4 |
| Chimneys, stacks, trussed towers and tanks: | ||
| Supported on or projecting as an unbraced cantilever above the roof more than one-half its total height | 2.4 | |
| All others including those supported below the roof with unbraced projection above the roof less than one-half its height or braced or guyed to the structural frame at or above its center of mass | 0.9 | |
| Mechanical, plumbing and electrical equipment | 0.9 | |
| Anchorage for suspended ceilings and light fixtures | 0.9 |