Lateral Loading Test of Reinforced Concrete Bored Pile in Stiff Clay and Near Slope

Staff residence of University of Phayao has been constructed near slope. The inhabitants in the residence are concerned about the lateral strength of the pile foundation during earthquake. This paper involves the evaluation of reinforced concrete bored piles of the residence under lateral loading. In field experiment, two full-scale bored piles were built near the slope of 1:1.5 adjacent to the residence. Two lateral load patterns that push the piles in and out were applied at the pile head. The maximum value of the lateral force was 65 kN representing the base shear force due to earthquake in Thailand. The test results show that the lateral displacements of the pile do not exceed 3 mm and stress in the longitudinal reinforcement is below the yield point. It is implied that the bored piles of staff residence can resist the lateral load imposed on the structure during an earthquake. For the analysis, the pile is modeled using frame elements and the surrounding soil is assigned by horizontal springs. The stiffness of springs is validated by comparing to the test results of the previous researches and this study. It is found that using the proper soil spring stiffness and flexural rigidity values in the structural pile analysis can capture elastic responses including the lateral displacement, bending moment and depth of inflection point.