Pile capacity under oblique loads – evaluation from load–displacement curves

Abstract

Evaluation of pile capacity from load–displacement curves under oblique loads is an intricate task. Because under oblique loads, load–displacement curves do not exhibit a distinct plunge point. Several methods have been adopted by different researchers to evaluate pile capacity from load–displacement curves under oblique loads. A summary of all these methods has been presented in this paper. To delineate the effect of load inclination on pile capacity, the method opted, always plays an important role. It is the main factor which significantly affects the pile capacity quantitatively and leads to establish a distinct trend of load inclination on pile capacity. To illustrate the significance of opted method, an experimental study was conducted on 20 mm diameter and 600 mm length piles under oblique pullout loads of different inclinations. Pile capacity at each load inclination has been evaluated from load–displacement curves using three different methods. Results of one method indicate that there is an increase in pile capacity up to 10° of load inclination and thereafter it decreases as load inclination increases. Whereas, results of second method show that pile capacity continuously decreases as load inclination increases with pile axis. Decrease in pile capacity with increase in load inclination was also observed in the results of third method, but pile capacity at certain loads' inclinations significantly differs as compared to the second method with minimum at 45°. The paper also deliberates on the applicability of adopted methods as per serviceability and functionality requirements of system or structure to be supported by pile.