STRUCTURAL CAPACITY OF PRECAST PILES WITH GROUTED BASE

To improve the performance of a precast pile installed in a prebored h ole, a grouted base is often made around the base of the pile. The str uctural capacity of a precast pile with a grouted base was studied by three series of model loading tests. Two failure-mechanisms were obser ved, punching failure and splitting failure, which depended upon the g eometry of the grouted base. Punching failure occurs in cases in which the grouted base is thin, less than twice the pile diameter. In contr ast, splitting failure develops in cases in which the grouted base is thicker than twice the pile diameter. Structural capacity increases wi th increasing the thickness of grouted base. The effect of diameter of grouted base was also examined. Based on the experimental observation s, a theoretical model was developed to evaluate the structural capaci ty. The theoretical prediction agreed well with the experimental resul ts. A parametric study was performed to determine the optimum shape an d strength of the grouted base.