Dynamic and Stability Analyses of a Pedestrian Hybrid Steel-timber Arch Bridge with Composite Timber Arches

The dynamic and static behaviour of a pedestrian hybrid steel-timber arch bridge is investigated in this article. The main interest of this study is the modular design of the timber arches consisting of mechanically connected glulam beams. The individual arch segments are interconnected with a novel steel hinge connection. Dynamic and static tests were performed on a full-scale model of an arch segment (3.95 m long) in a laboratory. This study has been thoroughly presented in Bergenudd J, Battini J-M, Crocetti R. Nedev G, et al. [Analysis of a Mechanically Connected Timber Arch Section and Steel Hinge Connection for an Arch Bridge. In ICTB 2025. 5th International Conference on Timber Bridges, Rotorua, New Zealand, 2025] and only a summary is given in this article. In situ dynamic tests were performed on the finished bridge. The results showed that the partial composite action of the arches affected the out-of-plane modes of vibration and critical buckling load of the bridge substantially. The stiffness of the steel hinge connections in the arches reduced the critical buckling load of the bridge slightly. The analysis also showed that the slip modulus between the structural elements affected both the dynamic and buckling behaviours. Finally, the experimental damping ratios were around 1–1.5% for the bridge which is similar to the recommended values in the technical guidelines.