Nonlinear Soil-Structure Interaction of Bridge Pile Groups: from Experiments to Analysis and Back to Reality

抄録

Modernization of ageing motorway infrastructure poses a major engineering challenge worldwide. With respect to existing pile groups, any upgrade is not only a challenging, costly, and time-consuming operation, but it can also lead to significant indirect impact due to traffic deterioration. As part of a research project funded by the Swiss Federal Roads Office, this work examined the potential of avoiding such major operation by taking advantage of nonlinear foundation response. Evaluating a plethora of Swiss bridges, a simple –yet realistic– 2 × 1 bored pile group on saturated sand is selected as the prototype problem. The latter is examined in a combined experimental and numerical study. Initially, a series of model tests is conducted at the ETH Zurich drum centrifuge. The test campaign provides not only fundamental insights on pile group response, but also benchmark results for subsequent validation of finite element (FE) models. The numerical study initially focuses on model scale, showing good agreement between the FE model and the centrifuge tests. The unavoidable scale effects of centrifuge modelling are critically discussed and a careful transition is proposed from model to prototype scale. Back to reality, a parametric numerical analysis allows for the identification and quantification of the key resisting mechanisms. The conclusions of this work contribute towards optimized design of new and existing reinforced concrete (RC) pile groups.