This above referenced Excel Software Tool is provided for the determination (analysis) of lateral loads (Wind or Earthquake) transferred at Lateral Force Resisting System (LFRS) Gridlines, by floor diaphragms to Shear Walls (or other LFRS Elements at some locations), assuming Flexible Diaphragm Assumptions (FDA). These lateral loads, lumped at floor diaphragms, are transferred from the roof down to the foundation at building lines of resistance, to determine LFRS element and collector loads at every floor level.n.