A structurally supportive belly pad is connected to a rounded trailer and configured to support the same near the rear end of the trailer. The belly pad may be arcuately curved complementary to the curvature of the rounded trailer. However, if the belly pad were laid flat, it includes a pair of parallel legs aligned in a generally longitudinal direction with a plurality of transverse ribs extending therebetween. The shape of the belly pad is configured to provide structural support for the trailer which is beneficial especially when the trailer is raised and lowered, typically through hydraulic mechanisms.