Susceptibility of Shallow Foundation to Rocking and Sliding Movements During Seismic Loading
Current design codes prevent the rocking and sliding of shallow foundations during seismic loading despite much research indicating the beneficial nature of allowing such movements. The primary benefit is the partial isolation of the structure from the soil beneath and subsequently the reduced ductility demands on the superstructure, saving money and reducing the risk of collapse. However, further research is required in order to be able to fully model and predict the behaviour of the soil-foundation interface when sliding and rocking is permitted. The results presented in this chapter examine how several different parameters including structural stiffness, aspect ratio, soil relative density and earthquake magnitude affect the level of rotation and sliding experienced by the foundation. Six centrifuge tests were performed to examine how these parameters affected the response of the structure and high speed photography was used to track the movements of the foundation precisely. It was found that structures with a high centre of gravity slid more than structures with a low centre of gravity. Also, stiff structures were found to rotate more than flexible structures and structures located on dense sand rotate more than those located on loose sand.
KeywordsParticle Image Velocimetry Flexible Structure Stiff Structure Input Motion Loose Sand
The research leading to these results has received funding from the European Community’s Seventh Framework Programme [FP7/2007–2013] under grant agreement no 227887 [SERIES]. The support of the other members of JRA3 in SERIES is acknowledged.
- Flavigny E, Desrues J, Palayer B (1990) Le sable d’Hostun. Géotechnique 53:67–70Google Scholar
- Garnier J, Gaudin C (2007) Technical Committee TC2 – physical modelling in geotechnics catalogue of scaling laws and similitude questions in centrifuge modellingGoogle Scholar
- Kutter BL, Kunnath SK (2010) Estimation of displacement demand for seismic design of bridges with rocking shallow foundations. In: 5th international conference on recent advances in geotechnical & earthquake engineering and soil dynamics, San Diego, p SOAP11Google Scholar
- Madabhushi S, Schofield A, Lesley S (1998) A new stored angular momentum (SAM) based earthquake actuator. In: The international conference centrifuge ’98, Tokyo, Japan, pp 111–116Google Scholar
- Zhao Y et al (2006) Calibration and use of a new automatic sand pourer. In: 6th international conference in physical modelling in geotechnics, Hong Kong, pp 265–270Google Scholar