Evaluating the splitting capacity of timber beams loaded perpendicular to grain by bolted connections with steel plate: Experimental study and theoretical calculation

Timber structures have advantages such as green environmental protection and low-carbon energy conservation. Bolted connection with steel plate as one of the most commonly used dowel-type connections is widely used in timber structures. Nevertheless, the splitting capacity of timber beams loaded perpendicular to the grain by bolted connections with steel plate is influenced by various factors, leading to significant differences in calculation formulas and outcomes. On the basis of preliminary experimental research, a total of 113 timber beams and 6 bamboo glulam beams with steel plate bolted connections, loaded perpendicular to the grain, were tested and categorized into two main groups, with the consideration of the materials used for members and the total width of bolted connections. It was found that the splitting capacity of bolted connections loaded perpendicular to the grain increased along with the increase of material density of wood and bamboo. Essentially, a linear correlation was observed between the splitting capacity and the material density. In addition, the splitting capacity increased with an increase in the total width of connections and that the splitting capacity tended to be constant when the total width of connections reached a certain amount. Based on the test results and the current calculation model for splitting capacity, a modified model for calculating the splitting capacity of bolted connections loaded perpendicular to the grain was proposed. Notably, the average ratio of the calculated splitting capacity to literature-reported experimental results is 0.975. More importantly, the modified model, considering a comprehensive set of factors, offers broader application and improves usability for engineering designers.