Static performance of novel steel dovetail joints for single-layer grid shells under out-of-plane bending moments

A new joint system for single-layer grid shells with low costs, simple assembly, and clear load-bearing principles was developed in this study. Two types of novel steel dovetail joints without teeth pattern (interlock type I) and with teeth pattern (interlock type II) were subjected to bending moments. The specimens exhibited different bending moment-bearing capacities; the capacity of specimens with interlock type II was 255% of that of interlock type I. All test specimens underwent a similar failure mode when the beam-tail pulled out the hub-keyway from the bottom with hub ring deformation. The experimental results were verified by establishing FE models using Abaqus, and the numerical results agreed well with the experimental results. Moreover, a parametric study was conducted to evaluate the effects of design parameters on the performance of the novel steel dovetail joints under bending moments. It was found that the test bending moment was positively correlated to the height, ring thickness, and maximum thickness of the hub, whereas the hub diameter slightly influenced the bending capacities of these specimens. Finally, the rigidity values of the test specimens and their FE models were calculated according to Eurocode 3 specifications, and related equations for analysing the yield bending capacity were derived. The experimental, numerical, and theoretical results were consistent in high calculation validity and efficiency.

Automated summary

A new joint system for single-layer grid shells with low costs, simple assembly, and clear load-bearing principles was developed and tested through bending moment experiments and FE models. The study also evaluated the effects of design parameters on the performance of the joints under bending moments through a parametric study. The experimental, numerical, and theoretical results showed high calculation validity and efficiency.