Direct displacement based seismic design for timber flexible diaphragms in masonry shear wall buildings

• A proposed DDBD Analysis Methodology for flexible diaphragm buildings is discussed.
• A simplified method for analyzing flexible timber diaphragms is also considered.
• Compares the response of calibrated FEM models to both proposed methods.
• Recorded building response to earthquakes is also utilized for comparison.

A method for analyzing the seismic performance of timber flexible diaphragms based on the direct displacement based seismic design (DDBD) principles has been developed. The method utilizes knowledge of timber diaphragm seismic behavior, such as natural period calculation, force–displacement and ductility–damping relationships, developed previously by the authors. Accuracy of the method is illustrated through analysis of four prototype buildings and comparison to recorded data and numerical results. All four prototype buildings have timber diaphragms in conjunction with either reinforced or unreinforced masonry shear walls. Excellent agreement is found between the results from the proposed DDBD approach, and those from both the recorded data and finite element analysis. The proposed method provides a rational and consistent design methodology for flexible diaphragm buildings, which is lacking in ASCE-7.