Analysis of factors affecting the stability of large-span cable-braced timber gridshells

Global stability is a significant performance indicator for gridshell structures. This article takes the Dome of Taiyuan Botanical Garden, which is currently one of the largest timber quadrilateral gridshells in the world, as the research background to study the global stability of the large-span cable-braced timber gridshell system. It conducts a comprehensive parametric analysis of the influences of material nonlinearity, boundary conditions, joint stiffness, cable, and imperfections. The results indicate that introducing a cable-bracing system can significantly enhance the stability of the timber gridshell. An approximate logarithmic relationship between joint stiffness and the ultimate bearing capacity suggests that logarithmic curves can be used to design stacking joints in engineering. Furthermore, using the first-order buckling eigenmode as the imperfection shape is inappropriate since the first-order buckling mode may not be the most unfavorable imperfection shape. Instead, the failure modes of geometry nonlinear elastic analysis or geometry and material nonlinear analysis can be utilized as the imperfection shape. Finally, the influence of material nonlinearity on the stability of the cable-braced timber gridshell system may be less significant than that of the traditional gridshell systems.