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Limited research exists on the deformation compatibility behavior of mass timber beam-to-column connections. Therefore, to investigate this behavior, large-scale experimental monotonic testing was performed on five different glue-laminated (glulam) beam-to-column connections. The purpose of this research was to create a better fundamental understanding of the deformation compatibility behavior of mass timber beam-to-column connections. Three connections were custom-designed connections, and two were pre-engineered connections. Specimens included the presence of cross-laminated timber (CLT) decking on the beam, as well as combined lateral and gravity loading. Monotonic tests pushed specimens to a target story drift of 7.2% at a rate of 0.51 mm/s. The data were analyzed, and the yield force, yield displacement, initial stiffness, secant stiffness, and connection classification (categorized as either rigid, semirigid, or flexible) were calculated for each connection. Per the connection classification methodology used, all connections were classified as flexible (simple) connections. However, the pre-engineered connections use substantially more screws and plates thereby increasing the cost and effort of installation. The results demonstrate that in some cases simple custom connections can have a larger yield force and initial stiffness than pre-engineered connections, and due to the reduction in number of screws, there was less damage within the connection at the completion of the test. The forces required to push connections to 2% drift all exceeded the lateral force capacity of the connections; however, all connections maintained load-carrying capacity throughout testing. [ABSTRACT FROM AUTHOR]

The deformation compatibility behavior of glue-laminated (glulam) beam-to-column connections is not yet well understood. To investigate this behavior, 10 specimens representing five different glulam beam-to-column connections were tested under lateral cyclic loading. Three of the connections were custom-designed connections and two were pre-engineered connections. Specimens were large-scale glulam beam-to-column connections, and testing included combined gravity and lateral loading as well as the presence of a cross-laminated timber (CLT) deck. Connection characteristics such as yield force, initial stiffness, secant stiffness, and energy dissipation were calculated and compared across connections as well as observations made during testing. Results from the experimental testing indicated that pre-engineered connections demonstrated overall better performance than the custom connections. Pre-engineered connections had the largest remaining secant stiffness by the end of the loading protocol, greater energy dissipation, and larger average yield forces than the custom connections. Although all connections tested exceeded their lateral design capacities at drift levels less than 2% drift, all connections maintained load-carrying capacity throughout testing. [ABSTRACT FROM AUTHOR]

Connections play a vital role in the transfer of lateral forces and energy dissipation in cross-laminated timber (CLT) structural systems. However, moisture exposure (e.g., rain during or after construction) can affect the durability of CLT structural members and their connections due to the hygroscopic nature of wood. Limited knowledge exists on the moisture performance of CLT connections. Therefore, in this study, a CLT shear wall-to-diaphragm angle bracket connection was exposed to simulated rain and relative humidity cycling (wetting) and subsequent redrying followed by mechanical loading cyclic testing. Four wood species (Douglas-fir, southern pine, Norway spruce, and spruce-pine-fir) and three wetting durations were applied to understand the effect of moisture intrusion on the connection performance, which was evaluated in terms of strength, stiffness, and energy dissipation. Two force–displacement backbone models were fitted to the experimental data. The results suggest a statistically significant increase (9%–15% for different species) in the peak strength and no change in the stiffness and energy dissipation capacity after the wetting and redrying cycles. However, additional studies should be conducted to gain further insight into the observed increase in load-carrying capacity. Additionally, the authors caution against considering any strength increase until further studies are conducted. [ABSTRACT FROM AUTHOR]