Nonlinear In-Plane Deformation Mechanics of Timber Floor Diaphragms in Unreinforced Masonry Buildings

Abstract

An analytical model was developed to describe the nonlinear in-plane deformations of timber floor diaphragms in historic unreinforced masonry buildings. Diaphragm deformation mechanics are detailed for both principal-loading directions (parallel to joists and perpendicular to joists) and are shown to produce differential equations of identical form. The model is formulated based on the assumption of pinned-end conditions, symmetrical configurations, and a uniformly distributed applied lateral load. The model is validated against full-scale diaphragm experimental data and is shown to predict response in both principal-loading directions with good accuracy. It is recommended that further research be undertaken to establish representative parameter values for the governing nail connection load-slip function.