ENHANCING LATERAL BEARING CAPACITY OF PILES IN MEDIUM DENSE SAND BY WINGED STIFFENERS

Carrying capacity of laterally-loaded piles depends on the passive lateral resistance of soil, which is relatively weak near ground surface. The aim of this research is to examine the effectiveness of stiffening steel piles with a number of strips, which are termed as pile wings, welded on the external circumference of each pile. The study investigates the effect of wing length and group spacing on the lateral carrying capacity of piles. The study is conducted on a small scale experimental model and a prototype numerical model. The study also extends to determine the required modification to be applied to the Characteristic Load Method, CLM. It is concluded that providing piles with stiffening wings has a considerable effect on enhancing the pile lateral carrying capacity and reducing pile head deflection. The enhancement is improved with increasing wing length. Rigid piles fail by rotation due to yielding of soil near ground surface and above pile tip. For unwinged pile group with a spacing of three times the pile diameter or more, each pile acts as a single pile. A spacing of four times· pile diameter is more appropriate in case of winged pile group. The charts and curves of CLM can be used for winged piles by applying a modification to the pile inertia.