A Hybrid Simulation Based Method for Post Seismic Structural Health Monitoring of Concrete Bridges

The present study reports on development of a hybrid simulation based method for post earthquake structural health monitoring of concrete bridges. Linking between filed and laboratory facilities through a limited number of sensors, the proposed method provides the possibility to monitor the behavior of the most vulnerable components of a bridge structure more comprehensively. To investigate the feasibility of the introduced methodology, an experimental program was planned to perform the hybrid simulations on 1/10, 1/8 and 1/6 scaled models of a two-span bridge subjected to progressively increasing amplitudes of seismic motions. Hybrid simulation is an experimental testing methodology performed on a hybrid model which is composed of scaled physical and numerical components of a structural system. The experimental and analytical portions incorporated into a single model by compelling the displacement compatibility and the force equilibrium at the common nodes. All the components of the bridge structure studied in this research, except one column, were simulated numerically in the analytical part of the hybrid models. The physical part of the hybrid simulations consists of well confined reinforced concrete columns instrumented with an array of surface adhered and embedded fiber optic sensors along the diameter of the circular cross section in the plastic hinge zone. The results of shaking table tests on a 1/4 scaled model of the bridge were used to study the accuracy and reliability of different scales of the hybrid simulations. The data obtained from the sensors were employed for analysis of damage in the bridge columns. The developed embedded sensors along with the external sensors were used to picture the redistribution of strains in the cross section of plastic hinge area. Performance assessment of bridge structures equipped by structural health monitoring systems requires the development of deterministic methodologies producing quantitative information on different damage states. A novel methodology is developed to evaluate the energy dissipation in a reinforced concrete column with circular cross section based on the curvatures measured in the plastic hinge area. Dissipated energy is a sensitive quantity to monitor the progression of damage in structures. Integrating the introduced method in a normalized dissipated energy index provides the possibility to detect and quantify minor and moderate damages which are barely visible during visual inspection.