Numerical investigation of drilled shafts near an embankment slope under combined torque-lateral load scenario

Generally, cantilevered structure-foundation systems supporting highway signs, signals, and luminaires in the areas exposed to severe wind loadings (e.g., hurricane) have been designed under coupled torsion and lateral load scenario. Especially, mast arm cantilevered structures constructed near or on an embankment slope may have more concerns on the torsional and lateral resistance of the foundation. However, most research works have merely considered drilled shaft foundations under torsion-lateral load case with an embankment in proximity. In this study, a numerical study is performed with different soil layers to: (1) understand the combined torque-lateral load behavior of drilled shafts near an embankment slope; (2) examine the effect of both the torsion and lateral resistances in the proximity of an embankment slope. It was found that torsional stiffness decreases with increase in slope angles. Finally, design criteria (e.g., minimum allowable distance from the embankment, maximum allowable point load near the embankment) of the mast arm assembly and loads are provided.