Influence of Seasonal Changes on Inclined Load Tests on Drilled Shafts

Drilled shafts are used at both ends of a barrier system to support the cables. The intent of the drilled shafts is to transfer or absorb the tensile and traffic impact loads transpired in the cables via uplift and lateral load resistances of the shaft. Even though drilled shafts can be constructed in most types of soils and function well, drilled shafts constructed in problematic soils, such as high-plasticity clay, have failed due to high uplift forces along the contact area of the shafts with the surrounding soils. Appropriate foundation design is critical to address the excessive lateral movements from the external loads and internal uplifts coming from expansive clays due to shrink and swell movements from dry and wet moisture conditions, respectively. This paper provides the results of a several field tests conducted on drilled shafts of different dimensions in summer (dry and hot) and winter (wet and cold) conditions from a unique loading test setup that utilizes a static and inclined tensile loading on the shafts simulating natural environment. Test results are analyzed to explain the effects of seasonal conditions on load responses of drilled shafts of different dimensions.