Seasonal Freezing Effects on the Lateral Behavior of Steel Pipe Piles

摘要

Frozen ground is significantly stiffer than unfrozen ground. For bridges supported on deep foundations, the bridge stiffness is also measurably increased in the winter months. Significant changes in the bridge pier boundary conditions due to seasonal freezing requires additional detailing to ensure a ductile performance of the bridge during the design earthquake event. Currently, there are no design guidelines for including the effects of seasonal freezing in seismic analysis. A project has been initiated to systematically investigate the effects of seasonal freezing on the seismic behavior of bridges in cold regions. This paper presents the numerical simulation results of an extended reinforced concrete-filled steel pipe pile-shaft system that is to be tested in outdoor conditions. By using the OpenSees computational platform, a nonlinear three-dimensional Finite Element model is established to investigate seasonal freezing effects on the lateral behavior of the soil-pile system. Pushover analysis of the soil-pile system embedded in the experimental site has been performed to predict its lateral behavior. The results demonstrate that the effects of seasonal freezing have a significant impact on the lateral yield force and displacement capacity of the soil-pile system.The location and rotation of plastic hinges are also greatly affected.