Document Type : Structural Earthquake Engineering
The modeling and analysis of structures subjected to earthquake loading are well studied and understood. During an earthquake, however, the behavior of the soil under the structure plays an important role in determining the superstructure response. In most cases, the soil is not modeled and is ignored. This is due to the reason that the soil, contrary to the structure, is an infinite domain and can not be treated with the conventional models as used in structures. Cone models to represent the soil, have been developed for practical engineering applications during the last ten years. Cone models can be utilized for sites with general layering and embedment conditions, capturing all degrees of freedom. Cone models provide sufficient engineering accuracy with physical insight. Cone models can be used both in force-based methods as response spectrum and time history analyses and in displacement-based methods such as push-over calculations. In these models, the soil is represented with a series of bars and beams as one uses in the analysis of superstructures. In this paper, the development of cone models is reviewed. Further, the application of the cone models in two actual seismic retrofitting projects is demonstrated. In both cases, the retrofitting costs were reduced substantially after modeling the soil with cones.