Masonry construction comprises a large portion of building construction in the U. S. and the world. Reinforced masonry construction use is increasing in moderate to higher seismic zones because of its apparent features of economy, fire safety, architectural flexibility and ease of construction. The present state of masonry structural analysis and design, and materials and construction technologies does not enable an accurate prediction of building behavior under lateral loads such as seismic loads. In the U.S., masonry buildings are designed and built with methods, codes and standards that rely upon a mixture of working stress methods, empirical rules, and questionable methods for determining allowable stress values. Masonry is also a complex building material because of the large number of design and construction variables which influence the final product configuration and its response under seismic loads. In order to describe the seismic response of masonry buildings it is necessary to develop the fundamental knowledge base to determine basic design methodologies consistent with safety and economic requirements. This research project examines concrete plank diaphragm characteristics and considers the effect on diaphragm action of a change in the stiffness of the supporting members. This is done by substituting masonry walls in place of steel I-beams. Data are used to determine strength, seismic behavior characteristics, and failure modes. An analytical model is determined to describe this type of system. The results of the research provide a link between experimental data and actual systems which are used in masonry structures. This project is part of the U.S.-Japan Coordinated Program for Masonry Building Research and the Technical Coordinating Committee for Masonry Research (TCCMAR) Program.
