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The ductility-related force modification Factor Rd, and overstrength-related force modification factor Ro is input. The default values are from according to NBC Table 4.1.8.9 Ro = 1.7 and Rd = 3.0 for wood. For gypsum materials Rd = 3.0. The program automatically detects the presence of gypsum in a force direction and prompts you to change the Rd value.
The default R values are the ones for wall that include gypsum wallboard panels, because the default standard walls include GWB. Upon generating loads, if the program detects the presence of gypsum wallboard in a particular direction, it warns you and offers to change the R value to the one corresponding to "all other materials". If you choose to use an R value for wood materials in the presence of GWB then the program automatically checks the Disable gypsum contribution.. design setting, so that the gypsum materials do not contribute to shear wall strength.