Seismic assessment of low-rise shear wall buildings with non-rigid diaphragms

In current practice, many approaches for building structural analysis focus on two-dimensional and/or linear elastic idealizations of the response. Nevertheless, the earthquake behavior of low-rise shear wall buildings with non-rigid diaphragms can be highly three-dimensional, and the performance of these systems can depend significantly on the inelastic response of their components. Key modes of response may include both in-plane and out-of-plane wall deformations, and combined diaphragm flexural deformations in two principal directions with diaphragm shear raking displacements. The diaphragm flexibility can significantly influence the out-of-plane wall displacements. The distribution of lateral loads to the structural walls and the degree of torsional coupling between the wall systems can be strongly dependent on the flexibility of the diaphragms and the inelastic system behavior.; This research investigates the seismic assessment of shear wall buildings with non-rigid diaphragms. The focus of this work includes the creation and investigation of a simplified multiple degree-of-freedom (MDOF) linear or nonlinear three-dimensional analysis approach that accounts for diaphragm flexibility in buildings of rectangular plan geometry. The number of degrees-of-freedom in the simplified analysis approach is kept as small as possible while still permitting capture of the three-dimensional effects mentioned above. A computer graphics system is developed for visualizing the physical three-dimensional behavior predicted by the simplified MDOF models.; The above analysis tools are applied to a two-story historic unreinforced masonry building from which earthquake field data is available, and to a half-scale one-story reinforced masonry building that has been subjected to shaking table tests in prior research.{09}These studies focus on defining appropriate structural properties for accurate prediction of the dynamic responses using the proposed simplified MDOF procedure. This research concludes with the investigation of a simplified linear static methodology applicable for flexible diaphragm structures. The advantages and limitations of this methodology are assessed by comparison of its predictions to experimental and time history analysis results.