Determination of Ultimate Pile Bearing Capacity from a Seismic Method of Shear Wave Velocity in Comparison with Conventional Methods

Abstract

The seismic method in the ultimate bearing capacity of piles based on shear wave velocity measurement is a new technique in geotechnical engineering design. In this study, the value of shear wave velocity, Vs is being successfully used to formulate a theory to determine the ultimate bearing capacity of piles.   This theory is adapted from the ultimate bearing capacity of shallow foundation proposed by Keceli. Keceli’s formula is adapted by equating the pile tip vertical resistance of the seismic formula to the end bearing capacity of the pile tip for each layer. The sum of half the vertical resistance of each layer is then equated to the total shaft resistance of the pile. The end tip is then added to the total shaft resistance to give the total ultimate pile bearing capacity of the pile. This study was conducted at three sites, two sites of residual soil located in Malaysia and one site of alluvial soil situated at Collierville, Tennessee, USA. The results of the adapted seismic formula were compared with the static pile bearing capacities calculated using conventional methods proposed by Meyerhof for the SPT-N values and the Schmertmann, Bustamante and Gianeslli method for the SCPTu values. The percentage error in the ultimate bearing capacity of the piles between the adapted seismic and the conventional methods for all the sites were found to be -4.77%, -3.01% and -0.93% at Hulu Langat, Mutiara Damansara and Collierville sites respectively.