Rotated Thrust Network Analysis (rTNA) for stability assessment of vaulted structures subjected to horizontal loading

Abstract

Thrust network analyses are commonly used in the stability analysis of three-dimensional masonry structures. Stability under gravity loading is ensured if a permissible thrust network can exist within the geometry of a structure. The maximum and minimum thrust networks are typically found using linear optimisation of the thrust network coordinates along the axis aligned with the gravity loading. When subject to lateral loading, optimisation along this axis does not result in equilibrium thrust networks. To address this issue, optimisation of the thrust network needs to be coordinated along an axis aligned with the resultant of gravity and lateral loading. In this paper, an extended thrust network analysis is presented that uses a stepwise procedure to effectively rotate the optimisation axis. This rotated Thrust Network Analysis (rTNA) results in more conservative solutions for the case examined of a spherical dome subject gravity and lateral loading. Numerical applications of the method, with the inclusion of lateral loading, are shown for changes in the embrace angle of a spherical dome and the effect of reduction in the acceleration due to gravity that may be experienced in the lunar environment.