How does WoodWorks® Shearwalls 2004 calculate and apply the Seismic Reliability factor, ρ?
The seismic reliability factor ρ takes into account structural redundancy in the lateral force resisting system, and is used to modify any forces induced by horizontal earthquake loads as described in Section 9.5.2.4, pp 128-9 of ASCE-7 and Section 1630.1.1, p 2-13 of the UBC. In general, this factor applies to buildings that are much longer than they are wide, or have very short shear resisting elements along the shearlines. Applicable Seismic Zones The application of this factor is restricted to UBC Seismic Zones 3 and 4, and ASCE-7 Seismic Design Categories D, E, and F. Shearwalls implements these restrictions. Most heavily loaded element The calculation of ρ involves the shear applied to the most heavily loaded element on a story. Shearwalls considers an “element” to be a full height sheathing segment between openings. Maximum Element-to-Storey Shear Ratio rMAX or r, This is the ratio of the design storey shear resisted by the most heavily loaded single element, to the total design
