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Important Note – These are descriptions to changes implemented in WoodWorks Shearwalls for version 10.0 and may not reflect current behavior
You are now able to specify ρ instead of having the program calculate it, and the factor has been removed from the body of the Seismic Information table to the notes below.
Because the calculations for are complex and Shearwalls cannot take into account detailed structural features, and shearwall design and rigidity-based load distribution is quite sensitive to changes in the redundancy factor ρ, we have added the capability of over-riding the program calculations and specifying your own ρ value.
To the building site dialog two combo boxes have been added for entering ρ for the east-west direction and ρ for the north-south direction; the choices are Calculated, 1.0 or 1.3.
During design, if either 1.0 or 1.3 has been selected for ρ, then the selected value is used and the building is designed. If you specify that ρ is calculated, then for the initial design pass, rho is set to 1.0.; after design, ρ is calculated and if it is 1.3 then the design is redone using a rho of 1.3. This is done independently in both directions.
The redundancy factor has been removed from the body of the Seismic Information table because, since ASCE 7 2005, it no longer varies from level to level. Instead a small section of text below the table gives
the factor in each direction,
whether it was entered by user , automatically calculated, or permitted to be 1.0 for categories B and C (Change 143)
the design code clause governing the factor
the range of seismic design categories for that clause.
If the factor is 1.3 rather than 1.0, a note says that it applies to shearwall design, hold-down forces, and drag strut forces, but not to story drift or out-of-plane forces.