Experimentell undersökning av smartphone-kamerabaserade mätningar för brotillämpningar ; : Experimental investigation of smartphone camera-based measurements for bridge applications

Bridges and buildings are designed for service life that exceeds a century, requiring resilience against diverseenvironmental and operational factors. To ensure safety, extend service life, and minimize costly repairs,structural health monitoring has become a critical tool in civil engineering. It enables the detection ofdeterioration and damage by capturing and analyzing in-situ data on structural behavior. With recent advancementsin sensing technologies and machine learning, structural health monitoring systems have evolvedsignificantly. However, key challenges persist, particularly in terms of cost, scalability, and accessibility ofmonitoring technologies. This study investigates the potential of using a smartphone camera as a low-cost andwidely accessible tool for structural health monitoring. Laboratory experiments were conducted to assess thefeasibility of both video-based and image-based measurement techniques in capturing structural responses.The collected data was analyzed to evaluate the accuracy and reliability of smartphone-based monitoring incomparison to conventional methods using accelerometers and Linear Variable Differential Transducers. Theresults show that smartphone cameras can capture structural displacements and vibrations with moderateaccuracy, particularly in cases involving large movements and low-frequency responses. However, significantlimitations were identified for small displacements, long measurement distances, and calibration reliability.While smartphone-based methods are not yet a replacement for conventional sensors, they offer valuableinsights into their potential for supplementary use and further development in structural health monitoringapplications.