Effective time integration strategies for dynamical response prediction under moving objects

In the context of time integration of (discrete) dynamical systems, complex vibration scenarios, e.g., for stiff structures, still present significant challenges to achieve affordable and reliable model response solutions. This study considers the dynamical vibration context of moving-object problems (such as Moving Load, Moving Mass or Moving Oscillator), to identify effective strategies for simulating representative deflections of continuous beams under moving-object conditions. The goal is that of acquiring accurate time histories of all displacement, velocity and, most critically, acceleration response variables, within these scenarios. A reliable simulation of structural responses, induced by moving objects, shall display crucial practical implications toward effective Structural Health Monitoring (SHM) processes of infrastructures, relying on experimental measurements, particularly in the areas of system identification and digital twin replication, supporting informed management and maintenance strategies. The present research is specifically conducted within the framework of setting a robust SHM platform for the historic railway and road iron arch bridge at Paderno d’Adda (1889), whereby digitally replicating the structural response to moving objects looks both challenging and essential, in requiring a close matching among numerically evaluated and measured responses. A Multiple Moving Load condition of physical objects representing convoys/vehicles travelling at constant speed is herein specifically analyzed, on the multi-span upper continuous beam of the iconic bridge, on ideally firm supports, with rather interesting results, about the amount of vibration, according to the position of the moving objects along the beam.