Flexural Strength and Ductility of Extended Pile-Shafts. II: Experimental Study

Results of an experimental program investigating the lateral strength and ductility capacity of reinforced concrete piles are presented. Four full-scale reinforced concrete piles with details representative of the current California design were tested under combined axial compression and reversed cyclic lateral displacement. Test parameters include confining steel ratio, aboveground height, and soil density. Of particular interests are the lateral strength and stiffness of the soil-pile system, depth-to-maximum-moment, and magnitude of local deformation upon formation of a plastic hinge in the pile. Equivalent plastic hinge lengths were determined using curvatures measured along the length of the pile. Test results indicated that the equivalent plastic hinge length of piles is generally longer than that of an equivalent base-restrained column. The equivalent plastic hinge length of the pile depends primarily on the aboveground height of the pile, but is not overly sensitive to the soil density. Test results also provided the basis for an analytical model presented in a companion paper for assessing the local ductility demand of a yielding pile-shaft.