LOAD DISPLACEMENT RESPONSE OF PILES UNDER DIFFERENT LOADING CONDITIONS

Abstract

Deep foundations are commonly used in large civil engineering structures. Deep foundations transfer the loads from the superstructure to more stable ground layers taking into consideration the allowable displacement and ultimate capacity. A good characterization of soil parameters plays an essential role in pile design. Thus, new site-specific correlations are developed between the clay strength obtained from tests performed on high-quality Shelby tube specimens and in-situ test results. In the current research, the load-displacement results from full-scale pile load tests performed in Al-Burrulus are analyzed. The ultimate pile capacities are back-calculated from the load tests under the different loading conditions (compression, tension, and lateral) and compared with capacities obtained from the analytical method. Moreover, the field load-displacement curves of axially loaded piles in compression are compared with the theoretical load-displacement response provided by (ECP 202). Additionally, the current study presents the back analysis of field pile load tests using the finite element method program “Plaxis 3D” using the Mohr-Coulomb model. The analysis aims to back-calculate operational soil stiffness through using the small strain shear modulus Gmax as the initial value for soil modulus. New modulus degradation curves are developed for bored piles under compression, tension, and lateral loading. Finally, the relations between the back-calculated soil modulus and depth ratio are presented.