Influence of the Initial Prestress Level on the Reliability Index of Geiger Dome

This paper presents a reliability analysis of four distinct design solutions, known as Geiger domes. These domes possess two intrinsic characteristics of tensegrity structures: infinitesimal mechanisms and self-stress states. In the absence of self-stress (initial prestress), Geiger domes are inherently unstable; stabilization is achieved only through the introduction of initial prestressing forces. The reliability analysis is carried out using a system-based approach and focuses on domes with six load-bearing girders. Two girder geometries are examined: one with a closed upper section and the other with an open upper section. The primary aim of this study is to identify a design solution that is more sensitive to the influence of initial prestress on structural reliability. Accordingly, the reliability index is evaluated as a function of the initial prestress level. Within the system-based framework, the reliability assessment of tensegrity structures is conducted in three stages. The first stage involves identifying self-stress states and infinitesimal mechanisms. The second stage concerns the formulation of reliability models, while the third stage evaluates the effect of initial prestress on the reliability index. Research has shown that the best solution is the original Geiger dome.