LAUSR

Abstract The target of this study is to develop a robustness index for parallel load-bearing systems. Parallel load-bearing systems are structural systems with load-bearing elements that are similar in type and function and constitute alternative load paths. For this purpose, a conceptual model is considered. The robustness index will be calculated based on the “stress increase ratio” of the critical cable in a cable-loss scenario. For finding the stress increase ratio of the critical cable, the differential equations of the system have been used. Accordingly, the stress increase ratio of the critical cable has been calculated by deriving an approximation function. In order to maximize the accuracy of the approximation function, the least squares method (LSM) has been used. Then, a reserve-based robustness index for a parallel load-bearing system has been derived. The proposed robustness index considers different levels of the initial damage and can be expanded to account for the initial failure of several load-bearing elements. The developed robustness index has been checked by numerical models and its good accuracy has been proven.