The long-term (after end of construction) behavior of large-span culverts buried in cohesive soils is presented. Nine centrifuge tests encompassing three different culvert shapes and three soils of varying degrees of plasticity were conducted. Backfill depth over the crown was fixed at 4.8 m to minimize the effect of vehicular live loads and to represent field conditions. The results show that the culvert's original shape controls its deformed shape and possible failure mode. For instance, the crowns of the semicircular culverts were rising, whereas the crowns of the low-profile arches were subsiding. The soil's plasticity was related to the magnitude of stress and deformation increase, and a linear relationship between bending moment and soil plasticity was discovered. In general, axial stress increases of 10 to 50 percent and bending moment increases of 50 to 100 percent, depending on soil plasticity, were recorded. It is suggested that long-term stress changes be accounted for in the future design of cohesive soils.