Linear static analysis of low-rise buildings with flexible diaphragms using the structural separation method

Current seismic codes and standards generally use an equivalent single degree-of-freedom (SDOF) model for low-rise buildings with rigid diaphragms. However, flexible diaphragm structures behave in general as multiple degree-of-freedom (MDOF) systems. A simplified linear static methodology, applicable to buildings with flexible diaphragms, is proposed in this paper. The procedure is based on the assumption that the diaphragm stiffnesses are small relative to the stiffness of the walls, and that the flexible diaphragms within the structure tend to respond independently of one another. Based on these assumptions, flexible diaphragm buildings can be analyzed by conducting separate analyses of subassembly models at each of the diaphragms, then additively combining the results from the separate models. This approach is referred to in this paper as the structural separation method.