Structural Identification of Civil Engineering Structures

Abstract: The assumptions encountered during the analysis and design of civil engineering structures lead to a difference in the structural behavior between calculations based models and real structures. Moreover, the recent approach in civil engineering nowadays is to rely on the performance-based design approaches, which give more importance for durability, serviceability limit states, and maintenance. Structural identification (St-Id) approach was utilized to bridge the gap between the real structure and the model. The St-Id procedure can be utilized to evaluate the structures health, damage detection, and efficiency. Despite the enormous developments in parametric time-domain identification methods, their relative merits and performance as correlated to the vibrating structures are still incomplete due to the lack of comparative studies under various test conditions and the lack of extended applications and verification of these methods with real-life data. This licentiate thesis focuses on the applications of the parametric models and non-parametric models of the System Identification approach to assist in a better understanding of their potentials, while proposing a novel strategy by combining this approach with the utilization of the Singular Value Decomposition (SVD) and the Complex Mode Indicator Function (CMIF) curves based techniques in the damage detection of structures. In this work, the problems of identification of the vertical frequencies of the top storey in a multi-storey¸ building prefabricated from reinforced concrete in Stockholm, and the existence of damage and damage locations for a bench mark steel frame are investigated. Moreover, the non-parametric structural identification approach to investigate the amount of variations in the modal characteristics (frequency, damping, and modes shapes) for a railway steel bridge will be presented.