Developing the Application of Strain Energy Spectrum in the Health Monitoring of Steel Resistance Frame Structures

Structures are subjected to different kinds of loads during their lifetime, such as those caused by daily temperature swings, traffic loads, abrasion and severe loads like earthquake.  The occurrence of damage in building structures, oil platforms, and generally all structural systems is inevitable. Different kinds of failure in various engineering structures have been observed so far, which have incurred massive financial losses and serious casualties. Most of such damages could be identified with structural condition assessment, and therefore crack propagation in and total collapse of the structure can be prevented by taking rehabilitation measures. The fact that in seismic prone regions where the occurrence of minor and local damages could lead to the total collapse of the structure increases the importance of structural health monitoring substantially. Hence, determining the damages in structures in order to monitor structural health, increase the safety of the structure, and determining the current condition of the structure seems vital. In this research, spectral strain energy is considered as an index for determining the location of the damage. By making a comparison between the spectral strain energy of healthy structure and damaged structure, damaged elements can be identified. In addition, the capability of the aforementioned method in the linear and nonlinear regimes will be assessed. To demonstrate the efficiency of the adopted procedure, numerical examples are provided whose results indicate precision and suitable performance of the proposed method in identifying damages in structures.