Experimental study and analytical model of bolted connections under monotonic loading

Abstract

Dowel-type connections are essential components of safe, economical timber buildings. This study analyzes the mechanical properties of different configurations of bolted connections with slotted-in steel plates. The test results indicate that the parallel-to-the-grain connections exhibited three typical failure modes, whereas wood cracking was the predominant failure mode of the connections perpendicular-to-the-grain. The mechanical properties, such as initial stiffness, yielding load, maximum load capacity and ductility, are obtained from load-displacement curves and compared with a design code. The relationship among the mechanical properties, bolt diameter and the thickness of glulam timber is investigated. Based on the experimental load-displacement curves, a two-parameter analytical model related to the initial stiffness and load-carrying capacity is proposed for the prediction of nonlinear load-displacement behavior, and the curves generated using the analytical model are consistent with the test curves. The two physical parameters can also be calculated using the design formulas, rendering the analytical model more useful in practice. This work is beneficial by contributing mechanical knowledge and providing a database for improved connection designs in timber engineering.