Performance of glued-in rod timber joints under seawater and UV exposure cycles

Timber joints with glued-in rod connections provide an interesting technical solution for numerous structural applications, also under harsh environmental conditions; yet little research is available on this topic. This paper experimentally investigated the effect of exposure to seawater wetting/drying cycles and seawater wetting/ drying plus UV radiation cycles on the pull-out performance of glued-in rod timber connections. Three rod diameters, three anchorage lengths, and four exposures were considered, leading to manufacturing and testing a total of 189 specimens. The quasi-static monotonic pull-out resistance of joints was a function of rod diameter and anchorage length as well as exposure, with larger numbers of exposure cycles changing the failure mode from ductile to brittle. A strength reduction of up to 53% was observed for timber joints subjected to 90 cycles of seawater wetting/drying plus UV radiation. Based on these results, an environmental condition reduction factor is proposed to account for the reduced connection resistance under harsh environmental conditions.