Abstract
Foundations supporting electrical transmission line structures are subjected to inclined loads due to gravity dead and live loads, and lateral wind loads. Due to land limitation and linear alignment of transmission lines, many structures are supported by drilled shafts installed in sand near sloping grounds. This paper evaluates the performance and ultimate capacity of piers installed in sand and subjected to inclined loading through a laboratory experimental program. A series of 1 g experimental model tests was conducted on fully instrumented model piers to evaluate their performance and ultimate capacity. The model pier was installed in a sand bed with a relative density of
70
%
at various setback distances from a slope and was subjected to various loading conditions. The results revealed that the peak soil pressure and the rotation point were captured at depths of
1.95
D
pier
and
0.74
L
pier
, respectively, below the ground surface in case of pure lateral loading. It was also found that, in case of pure vertical loading, 28.6% of the applied load was transmitted to the soil by the pier shaft resistance, indicating that the pier toe resistance had a significant contribution. The results, in addition, demonstrated that increasing the pier setback distance from the leads to a considerable increase in the pier capacity, and at a pier setback distance of
≥
10
D
from the slope edge, the pier capacity reaches that of a pier buried in a flat ground. Finally, the results indicated that the ultimate capacity of a pier buried in a flat ground under inclined loads was significantly greater by 16.67% than that of a pier in a flat ground under pure vertical loads.