In this study, finite element analyses are carried out to determine the reasons for the cracks and deflections occurred at a reinforced concrete box culvert constructed in the Necmettin Erbakan University campus, under a service road to allow the passage of rainwater. First of all, the sufficiency of the concrete grade, cross-sectional dimensions and the amount of reinforcement is verified by a linear elastic analysis carried out within SAP2000 commercial software. Later, by the inspection of the construction photos taken at the site, it is determined that the constructor did not fully comply with the projected reinforcement layout. In order to investigate the possible consequences of this fault, three dimensional finite element models utilizing solid finite elements and nonlinear material models are created within ABAQUS commercial software. Nonlinear analyses of the model with the projected reinforcement layout and the model having the reinforcement layout applied at the site are performed. As a result, not only it was possible to visualize which regions of the concrete had cracks, but also it was determined that there was considerable increase in the amount cracks at the top culvert platform at the model having faulty reinforcement layout.