Performance of Metal-Plated Wood Joints Exposed to Periods of Soaking Moisture

Abstract

Metal-plated wood truss systems may be rained upon during the construction phase, resulting in the soaking of the connections. In this paper, the results of an investigation of the behavior of metal-plated wood joints subjected to periods of soaking are presented. The wetting regimes included (1) 4-h shower, (2) alternating cycles of a period of shower wetting followed by a period of no shower, and (3) 24-h soaking in a water tank. Results of tests conducted after wetting and after wet-dry cycles were compared with results of dry control tests. The results show the wet joints lost over 40% of their load-carrying capacity in all three wetting regimes. Upon drying, the strength loss was about 10%. Likewise, the stiffness of the joints deteriorated, with stiffness loss ranging from 12 to 37%. In contrast to the load-carrying capacities, there were insignificant recoveries in joint stiffness upon the drying of the specimen, with additional loss of stiffness during the drying process in one of the groups investigated. The results of this study suggest the need to warn against severe wetting or to compensate for this probability of occurrence in truss design standards.