Numerical modelling strategies for the in-plane behavior of straight sheathed timber diaphragms

Two modelling approaches with different levels of refinement were employed to numerically investigate the influence of different parameters on the response of straight sheathed timber diaphragms when subjected to in-plane loading. The investigated parameters included diaphragm aspect ratio, scale factor (i.e. diaphragm size), impact of board-to-board contact phenomena, and the effects of board-to-board shear force exchange. The aim of the work presented herein was to use numerical modelling in order to investigate the aspects that potentially contribute to the difference in experimental behaviour reported in literature and that consequently might have influenced provisions encompassed in the most recent standards for the assessment of timber diaphragms (e.g. ASCE 41 and NZSEE). The modelling strategies were validated against a wide range of available experimental data on newly constructed and vintage timber floor specimens. Analysis results confirmed that the in-plane behavior of straight sheathed diaphragms is significantly influenced by parameters that are often neglected by numerical studies and assessment procedures.