Leaderboard

See the attachments. It answers your question and explains the fundamentals as well. Inelastic_Seismic_Behavior_Notes.pdf

A: In my opinion, both sides, this is to exclude an architectural projection e.g. a patio roof from this definition. A: ACI318-11 R21.11.7.5: "....collector elements of diaphragms are designed for force amplified by a factor Ω ..." so collector elements will be designed using overstrength factor in strength design method. A: diaphragm chord and drag members are not separate elements, they are part of the diaphragm. The components at the diaphragm boundary acting in tension and compression are known as tension chord and compression chord. Drag members have 2 types, collectors and distributors. Both are part of the diaphragm, a collector is an element that takes distributed load from the diaphragms and delivers it to the vertical element, a distributor takes force from the vertical element and distributes it into the diaphragm. See attached images. A: Motion of projecting wings can be ignored if dynamic analysis is performed along with finite element analysis aka ETABS model. A: If your stair case is not forming part of the lateral force resisting system and is not connected to diaphragm you can ignore this. A: Please see the attached flowchart published by SK Ghosh, it is very helpful.