Development of an Earthquake Motion Simulator and Its Application in Dynamic Centrifuge Testing

Keywords: Geotechnical Centrifuges, Verification of Liquefaction Analysis by Centrifuge Studies (VELACS), Ground Motion Simulators, Electrohydraulic Shakers, Servovalves, Hydraulic Systems, Testing Methods, and Earthquake Engineering.

Abstract: Centrifuge model studies of dynamics effects in soils are dependent upon the capability to simulate the excitation due to earthquakes. Various efforts have been made by experimentalists to design and develop such capabilities for existing geotechnical centrifuges. This study reports on the development of an electro-hydraulic earthquake motion simulator for the Princeton University geotechnical centrifuge. The success of the Princeton ground motion simulator indicates that application of electro-hydraulic shaker technology in centrifuge dynamic testing does not necessarily require high investments. The first group of tests performed with the electro-hydraulic ground motion simulator are part of the VELACS (Verification of Liquefaction Analysis by Centrifuge Studies) project. A soil deposit constructed with two layers, sand and silt, was tested to study dynamic behavior of non-uniform horizontal soil deposits. Next, an experimental study of soil-structure interaction effects was performed with geometry of the test corresponding to one of the collapsed Niigata apartments, damaged due to the liquefaction induced by 1964 Niigata earthquake. The experimental results are compared with results obtained from different methods of numerical analysis encompassed in computer codes DYNA1D and DYNA-FLOW developed at Princeton University.