Volume 35, Issue 2 (March 2012)
Inclined Tensile Load Testing on Short Drilled Shafts
Several drilled shafts supporting three-cable median barrier systems failed in North Texas during severe winter storms in 2006-2007. The original design of these foundations did not consider both uplift and lateral forces acting on the shafts at the same time. Since the barrier cables were fastened to the drilled shafts at an angle, it is hypothesized that an inclined pullout from both cable contraction due to seasonal temperature changes and soil softening may have contributed to the foundation failures. Hence, an attempt is made to design, conduct, and study inclined load tests on various drilled shafts of different dimensions. A total of twelve load tests were conducted on different drilled shafts in both summer and winter. This paper presents a summary of inclined load resistances of drilled shafts and vertical and horizontal movements from various types of instrumentation including the MEMS based system. The test results are also analyzed to explain the seasonal effects on the resistances of drilled shaft foundations.