Zheng Li

Large-span timber structures are increasingly used in modern construction, creating a growing demand for efficient structural systems such as glulam beam string arches. In such a system, glulam splice connections are often unavoidable because of fabrication, transportation, and erection limitations. However, the behaviour of these connections within a prestressed arch-string system is still not well understood, especially when the global geometry is also varied. This study experimentally investigates the structural behaviour of spliced glulam beam string arches with different splice types and geometric configurations. Eight specimens were tested under monotonic vertical loading to investigate the effects of splice details, rise-to-span ratios, and sag-to-span ratios. Two splice details, namely glued-in rod connections and bolted connections with slotted-in steel plates, were considered. The results show that the splice regions exhibited clear semi-rigid behaviour within the structural system, with equivalent rotational stiffness values of about 42.20%–56.79% of those of the unspliced reference sections. This local flexibility reduced bending continuity and contributed to deformation asymmetry and moment redistribution along the arch. Compared with the nominal splice type, the geometric configuration had a stronger influence on global stiffness, cable force development, and internal force distribution. A higher rise-to-span ratio enhanced arch action, while a deeper cable profile improved cable participation and prestress transfer. This study clarifies the coupled local-to-global behaviour of spliced glulam beam string arches, showing that splice flexibility should be interpreted as a system-level equivalent property rather than an isolated connection parameter. The findings provide experimental evidence for modelling and designing spliced long-span timber beam string systems.