AbstractBecause repetitive high strain caused by complicated deformation due to traffic load leads to fatigue damage in an orthotropic steel deck, reinforcement methods that suppress deformation are effective as a countermeasure. In Japan, a steel fiber–reinforced concrete (SFRC) pavement is often used as reinforcement to suppress deformation by improving the stiffness of the deck plate of the orthotropic steel deck. To appropriately evaluate the suppression of deformation, it is important to compare the deformation before and after reinforcement. In this study, the reinforcement effects of an SFRC pavement were verified based on visualizations of the deformation of a trough rib of an in-service orthotropic steel deck bridge before and after reinforcement by such a pavement. The visualization results showed that the deformation of the trough rib midway between the transverse ribs decreased after reinforcement, and the strain ranges at the weld joints between the deck plate and the trough rib decreased by approximately 18.5%–31.1%. On the other hand, at the intersection of the transverse rib, it was confirmed that the rotations of the lower flange of the trough rib increased after reinforcement. Accordingly, as inferred from the visualization results for the trough rib, the strain range of the web of the trough rib on the left side at the upper slit and that of the deck plate on the right side at the upper slit after reinforcement increased by approximately 10.6% and 47.5%, respectively.