Behaviors of socketed H-shaped steel piles

Abstract

A series of filed load tests and laboratory tests are conducted to investigate the pile deformation and the load transfer behavior of socketed H-shaped steel piles. The instrumented test results reveal that significant shaft resistance can be mobilized along the steel-grout interface. On the other hand, the H-shapes steel pile and the grout body cannot be assumed as a composite body in the evaluation of pile deformation. Laboratory bond tests are carried out on H-shaped steel/grout pile specimens. The bond test results indicat that the lateral confinement can significantly improve the bond strength along the steel-grout interface. Furthermore, if lateral confinement is provided, the welded steel studs can also improve the bond strength. Therefore, the steel-grout bond strength is not a constant along the depth in a socketed H-shaped steel pile. The comparison between the laboratory and the field test results demonstrate that slippage can occur along the steel-grout interface in the load tests. For short piles, the slippage can develop along the whole length above the socket section. For longer piles, slippage is likely to develop to a certain depth above the socket section. Such behaviors should be considered in the evaluation of the pile deformation under the vertical load. A modified calculation method for pile deformation is suggested. The pile deformation evaluated from the suggested method is closer to the field measured data than that the one from the local guidelines. In addition, more detailed analyses can be carried out for load test results by using the suggested method.