Bearing capacity of power transmission tower footings near cohesionless slopes

Many power transmission towers are situated near sloping grounds, and proper evaluation of their footing bearing capacity is essential for the safety and reliability of the critical power transmission lines. This paper investigates the ultimate bearing capacity of obliquely loaded square footings situated near cohesionless slopes. A series of experimental model tests and finite element analyses were carried out to assess the footing ultimate bearing capacity considering a range of ground slope configurations and soil properties. The investigated parameters include: slope height and inclination, footing setback distance from the slope edge as well as soil strength and relative density. Both experimental and numerical results revealed that an increase in the slope height and slope inclination and a decrease in the setback distance of the footing from the slope edge result in significant decrease in the footing capacity. It was also found that, as expected, load inclination and lower soil relative density resulted in further reduction of footing ultimate capacity. Finally, the results demonstrated that a setback distance of 2 to 5 B eliminated the effect of the slope on the footing ultimate bearing capacity.