Experimental study of the in-plan stiffness of timber floor diaphragms

The mechanical behaviour of horizontal diaphragms is an important parameter in the performance of a building undergoing seismic actions. The behaviour of a timber diaphragm is quite complex due to the local effects of its several components including the nailed connections and the unilateral contact. This study focuses on the experimental results of two timber floors with or without struts tested as diaphragms (blocked or unblocked diaphragm). Experimental set-up, instrumentation, material characteristics and the composition of the specimens are presented. Furthermore, the strength, the failure modes and the diaphragm stiffness behaviour while loading and the kinematic of the various components are also reported. The comparison with an analytical approach used to predict the in-plane displacement is performed and discussed. Elementary tests on components are also presented in order to provide the main information on mechanical parameters to be used in further numerical modelling.