Influence of Box Culverts on Behavior of Jointed Concrete Pavements

Structures underneath pavements commonly reduce the bearing capacity of the ground because of poor compaction and long-term settlement at sites around these structures. When a load is applied at these sites, the stress on the concrete slab increases and may exceed the design strength, inducing distress and shortening the lifespan of the pavement. In this study, we investigated the transverse cracking of concrete pavement slabs above box culverts in a test road of the Korea Expressway Corporation. Transverse cracking in the slabs was surveyed in both the north- and southbound lanes with different cover depths over the box culverts. To examine the transverse cracking, the jointed concrete pavement of the test road containing the culvert was modeled and analyzed by the finite-element method. Wheel loading was applied after taking into account the self-weight of the pavement and the temperature gradient within the concrete slab. The positions and magnitudes of the maximum tensile stress and the corresponding positions of wheel loading were investigated for each loading combination. In this manner, we identified the optimal joint positions for which the maximum tensile stress in the pavement slab is minimized. We also analyzed the behavior of the pavement in relation to the cover depth and reinforced concrete transition slab length. Accordingly, we proposed an appropriate length for the reinforced concrete transition slab to ensure minimized tensile stress in the pavement slab.