The above referenced Excel Software Tool is provided for determination of seismic loads to Steel Lateral Force Resisting System (LFRS) elements in Simple Buildings assuming Rigid Diaphragm Analysis (RDA) assumptions, where loads are distributed to resisting elements according to their relative stiffness and location away from the Center of Rotation (COR) of the rigid diaphragm.

Earthquake loads (EQ) are transferred by a Rigid Diaphragm (RC Slab or topped steel deck) at Floor Levels in building up to 20 stories per RDA assumptions to up to 32 Steel LFRS elements in both orthogonal directions within the specified diaphragm; steel elements can be Braced Frames whose stiffness is derived elsewhere (SCBF’s, EBF’s, etc), or Wide Flange (WF) Columns part of a Special Moment Resisting Frame (SMRF) whose stiffness is derived internally.