Sull'utilizzo del traffico veicolare per il monitoraggio di infrastrutture civili: la linea di influenza come indicatore di danno

This thesis introduces a low-cost monitoring technique that uses one or more accelerometers to survey the structural health of the bridge. Using bridge vibration due to vehicles, the method here presented, calculates the line of influence and use it as a damage-sensitive feature. Variations in the line of influence are used to reveal and estimate the structural damage. The proposed method is simulated using a MATLAB algorithm; the simulation takes into account the vehicle-bridge interaction and the roughness of the track. The car model used is a two-degree-of-freedom quarter car while, the bridge is represented by discretized one-dimensional FE beam elements. The vehicle bridge interaction problem is solved by an iterative method that use the contact forces for solving the equations of motion of the vehicle and the bridge; the Newmark beta method was used to solve each system of equations. The algorithm will be tested by simulating the transit of more vehicles in both directions of the bridge; In addition, more damage conditions will be introduced. The robustness of the method will be tested by varying the positions of the sensor, the speeds of the vehicles and by introducing an instrumental noise. Finally, for each simulation, a statistical study will be made to quantify the uncertainty of the line of influence estimates.