This paper experimentally investigates the feasibility of drive-by bridge monitoring for identifying the dynamic properties of a scaled concrete bridge using smartphone-based sensing. A one-fifth-scale laboratory bridge (3.8 m long, ~1300 kg) was instrumented with smartphone accelerometers mounted on both the bridge deck and a moving trolley representing a vehicle. Direct bridge monitoring was first conducted to establish benchmark modal properties, including natural frequencies, mode shapes, and damping ratios. These results were then compared with several drive-by configurations, ranging from partially mobile to fully mobile setups, under different excitation conditions such as hammer impacts and pedestrian loading. Partial drive-by monitoring achieved results comparable to the direct approach, whereas fully drive-by measurements without additional excitation showed limited effectiveness due to weak vibration transmission. The introduction of external excitation enabled successful extraction of bridge frequencies from vehiclemounted sensors. The study also demonstrates that scaled bridge geometry increases the difficulty of modal identification. Overall, the work provides valuable experimental evidence highlighting the roles of excitation energy, vehicle–bridge interaction, and structural complexity in drive-by monitoring performance.
Ren et al. (Fri,) studied this question.