|
|
|
|
|
Diaphragm Design Force
As per ASCE 7 12.10.2.2, for Seismic Design Categories C-F, the diaphragm design force Fpx from 12.10.1.1. is to be used to determine seismic forces on the diaphragm above the drag strut they are greater than forces derived from structural analysis using the base shear from 12.8. Refer to shear line force used for drag strut calculations for more details.
Overstrength Factor W0
The program does not apply the overstrength factor W0 factor to seismic drag strut forces, as the Exception to ASCE 7 12.10.2.1 says that it is not required for light-frame shear walls. However, W0 is applied to transfer forces from discontinuous shear lines on upper levels for this purpose; refer to shear line force used for drag strut calculations for more details.
Irregularity Increase
Shearwalls implements the 25% increase in seismic drag strut forces required by 12.3.3.4 for certain irregular structures; refer to Irregularities for more details.
Redundancy Factor r
The redundancy factor r from 12.3.4 is not applied to the component of the shear line forces derived from the diaphragm force Fpx from 10.2.1.1 as per exemption 7 of 12.3.4.1. r is not applied to transfer forces from discontinuous shear lines on the level above, as per exemptions 5 and 6. r is applied to continuous shear line forces from levels above on the same shear line as the drag strut, and to shear line forces derived from base shear using 12.8 if they govern for drag strut design.
Plan and Elevation View Drawings
In both Plan View, a Show/Hide menu option sallow you to view loads that are used for drag strut design based on the diaphragm design force rather than the loads used for shear line design. In both Plan View and Elevation view there is an option that allows you to view the shearline forces derived from these loads and factored by W0 and the irregularity increase where applicable, and not factored by r.