Tactile pressure sensors in centrifuge modeling of rocking foundations

The nonlinear response of shallow foundations when subjected to combined loading has been extensively studied by several researchers that have used sophisticated numerical tools and performed large or small-scale experimental investigations to explore the underlying mechanisms. It has been shown that failure in the form of soil yielding or foundation uplifting may accommodate high ductility demand and increase the safety margins, providing promising evidence for incorporation of such response in design provisions. The rocking response of a single degree of freedom system (SDOF) on sand was explored through a series of centrifuge tests that were performed at the Center for Earthquake Engineering Simulation (CEES) at Rensselaer Polytechnic Institute. The SDOF system was supported by a surface foundation and a tactile pressure sensor was placed at the soil-foundation interface to capture the evolution of the foundation contact area and the vertical stress distribution while the system was subjected to cyclic loading of increasing amplitude. The results obtained from experiments on loose and dense dry sand are discussed in this paper.