Characterization of mortar-timber and timber-timber cyclic friction in timber floor connections of masonry buildings

The seismic performance of buildings depends critically on the stiffness and strength of storey diaphragms. Whilst for modern reinforced concrete or steel structures the connection between floors and lateral resisting members is often assumed as monolithic, timber floors and ceilings in masonry buildings are susceptible to sliding in their supports. In fact, the anchorage of timber beams in masonry walls and intermediate supports relies partly or totally on a frictional type of resisting mechanism. The present work contributes to characterize this behaviour by presenting the results of an extensive experimental programme with cyclic friction triplet tests between mortar and timber units, and between timber and timber units. These were produced to be representative of connection typologies characteristic of pre-modern and contemporary construction periods. Each test was performed under a constant level of contact pressure, which was increased throughout each series to cover a range of normal forces foreseeable in building connections. Other aspects are also discussed, such as the influence of cumulative loading or velocity. The experimental data is made available for public use (10.5281/zenodo.3348328).