Ductility-Related Force Modification Factors of Wood Constructions with Shear Walls of Different Ductility

Ultimate Strength based Design (USD) method is a major seismic design method in Japan. Ductility Related Force Modification (DFM) Factor is the most important factor in USD method. Procedures obtaining DFM factors of dual or combined systems are not described in the code. But strengthening design need to calculate DFM factors of dual or combined systems, because those are often strengthened by different systems other than original systems. This paper proposes a Stiffness- Potential Energy Addition (SPEA) method in order to calculate lateral strength of stories with shear walls of different ductility. This method needs only two design lateral strengths for each type of shear walls in Damage Limit State and Safety Limit State. SPEA method also provides DFM factors of storied with shear walls of different ductility. SPEA method uses elastic stiffness and potential energy of each shear wall in a story.