Fig.7-1 Shafts and Rigid Frame subsystem (b)SHAFTS:(WALLS CAN BE SOLID OR TRUSSED) ROOF LOAD FLOOR OAD HORIZONTAL LOAD RESISTANCE RESISTANCE c)RIGID FRAMES:(REQUIRE STIFF COLUMN CONNECTORS) ROOF LOAD HORIZONTAL LOAD FLOOR LOAD 业业业业 3 7777 个 RESISTANCE RESISTANCEFig. 7-1 Shafts and Rigid Frame subsystem