| This thesis pursues the understanding of structural behaviour of steel space structures under various types of external loads including atmospheric and stress corrosion, the development of innovative yet practical algorithm for structural damage detection, the combination of health monitoring with vibration control towards a smart steel space structure, and the formation of integrated structural health monitoring and vibration control systems for the best protection of steel space structures. This thesis first presents a framework for evaluation of potential damage due to atmospheric corrosion to steel space structures through an integration of knowledge in material science and structural analysis. The research work on atmospheric corrosion of steel space structures is then extended by involving stress corrosion cracking to estimate corrosion damage to steel space structures in a more realistic way. The corrosion-induced fracture or local instability of a steel space structure may cause sudden stiffness reductions of some structural members, which will induce the discontinuity in acceleration response time histories recorded in the vicinity of damage location at damage time instant. An instantaneous damage index is proposed to detect the damage time instant, location, and severity of structures due to a sudden change of structural stiffness. The concept of integrated health monitoring and vibration control systems using semi-active friction dampers is introduced by means of a shear building subject to earthquake excitation. It is then applied to the reticulated steel shell with some adjustments in control algorithm and system identification procedure. In addition, the parameter identification and damage detection of the controlled structure can be performed in the time domain as long as the control forces can be measured. The equation of motion of the controlled structure is converted to the parametric identification equation when the inertia forces, damping forces, and restoring forces are linear functions of structural parameters. The conceptual design of an integrated health monitoring and vibration control system is finally performed in this thesis by taking the reticulated steel shell as an example with the aim of updating analytical models, identifying structural parameters, assessing structural safety, guiding maintenance and repairing work, and activating control devices to protect the structure against extreme loading. |
