Bracing
Transverse wind/seismic forces action on sidewalls of a metal building
are transferred to the foundation by means of “rigid frame action” of the
Primary Frames. At end walls with Bearing End Frames (which have
no “rigid frame action”), transverse wind/seismic forces are normally transferred
to the foundation by diaphragm action of the endwall sheeting. Longitudinal
wind/seismic forces acting on end walls are transferred to the foundation
by diaphragm action of the roof and sidewall sheeting and/or by rod (or
cable) bracing between frames.
Ceco’s engineers will design wind/seismic bracing to meet wind/seismic
load requirements for any given building. Diaphragm bracing will
be used whenever applicable, but will be supplemented and /or replaced
with rod (or cable) bracing when diaphragm capacity of sheeting is inadequate.
If building requirements preclude the use of rod bracing in sidewalls,
this “X” bracing will be replaced by either Cantilever Columns or Portal
Frames.
Even when the diaphragm capacity of the sheeting is adequate to meet
bracing requirements, any number of bays may be provided with “X” bracing
at the user’s request to help plumb and align the building. Minimum
size rods (or cables) are used for this alignment bracing since it is not
designed to carry any load either during erection or after the building
is completed. It will be, in all cases, the responsibility of the
erector to furnish and install adequate temporary bracing to maintain stability
of the structure during erection.