Design charts and equations of the frictional resistance of single pipe pile under static and seismic loads

Abstract

Foundations can be exposed to seismic loads in addition to static loads in seismic active areas. Thus, it might be necessary in this situation to use deep foundations rather than shallow foundations in order to prevent bearing capacity failure, improve the system’s dynamic stiffness, and/or minimize dynamic oscillations. In a seismically active area, the pile designer is expected to obtain at least the maximum earthquake-induced frictional resistance of the pile in order to achieve the necessary strength to ensure the structural integrity of the pipe pile is not compromised. However, determining the frictional resistance of the pipe pile is considered challenging. Therefore, in this study, design charts and new equations have been proposed to provide straightforward means to the designers to predict the frictional resistance of pipe piles embedded in dry and saturated cohesionless soils. The proposed charts and equations are for closed ended (CE) and open ended (OE) pipe piles. The charts have been developed based on the results of a validated three-dimensional finite element analysis. In addition, the equations were developed using regression analysis, where a high coefficient of correlation values is obtained (ranging between 0.94 and 0.98). The proposed predictive tools could assist designers in preliminary checks of the frictional capacity of pipe piles in seismic active areas.