Shaking Table Study on Bridge Model with Scoured Piled Foundation
Date Issued
2011
Date
2011
Author(s)
Lai, Zih-Yu
Abstract
In this study, the impact of scouring on the seismic performance of bridge pile foundation was investigated under multi-hazard circumstances. Large biaxial laminar shear box was tested on shaking table to simulate the scouring effect on bridge pile foundation. Test specimen is comprised of a bridge girder rested on a single column with a single degree of freedom, a single pile foundation and dry quartz sand. Different pile exposure lengths were the focus in parametric study to explore the effect of pile foundation on the seismic soil-structure interaction before and after scouring. Experimental results showed that the superstructure displacement increases as the pile exposure length increases, while the case is reversed for acceleration. The contact behavior of the footing and soil significantly influences the dynamic response of the superstructure. The maximum bending moment in the pile, constantly in the vicinity of the soil surface, lowers down as the exposure length increases, and the inflection point of the pile changes accordingly as well. Soil was simplified to be a single spring to efficiently simulate the soil-structure interaction. By comparing the test results and calculating the equivalent stiffness through the force of inertia and the deformation of soil, the seismic acceleration and displacement response of the superstructure can be effectively controlled for small ground motion. In addition, the applicability of the related empirical formula on soil spring in different bridge design codes was also studied. The experimental observation in this study reasonably coincides with the structural response defined by the pile spring theory according to the ‘Seismic Design Specifications for Highway’. Simulation methods of soil spring under strong ground motions need further investigation in the future to enhance the structural safety of bridges.
Subjects
Multi-hazard
Scouring effect
Shaking table test
Pile foundation
Soil-structure interaction
Soil spring
Type
thesis
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