Visualization of Deformation of Trough Rib of Orthotropic Steel Deck Under Live Load Using MEMS IMUs and Contact Displacement Gauges

An orthotropic steel deck has a structure in which thin steel plates (approximately 6–16 mm thick) are combined by welding. In this structure, displacement-induced fatigue damage often occurs due to complex deformation caused by traffic loads. To appropriately repair such damage and implement reinforcement, it is important to identify the deformation that caused the high strain. In this study, the deformation of trough ribs in an orthotropic steel deck caused by a live load was determined; using field measurements on an actual in-service bridge, with microelectromechanical systems (MEMS) inertial measurement units (IMUs), and contact displacement gauges to identify the mechanism causing the high strain. From the visualization results of the deformation, without performing finite-element (FE) analysis, it was found that one of the main causes of the high strain generated in the upper part of the trough rib was the bending deformation of the web of the trough rib. In addition, it was found from the visualized deformations that the transverse rib dramatically suppressed this deformation.