Report No.: CCEER-94-2

Stiffness Evaluation of Pile Foundation of Cazenovia Creek Overpass

Authors: Bruce Douglas, Emmanuel Maragakis, and Shiping Feng

Date: March 1994

Prepared for the:
Performing Organization:
Department of Civil Engineering/258
University of Nevada, Reno
Reno, NV 89557
Abstract:
A detailed study of a typical foundation of the southbound lane of the Cazenovia Creek Expressway was carried out and is described in this report. A 3-dimensional finite element model of the pier bent foundation was developed. The results presented in this report relate to the longitudinal lateral stiffness and the transverse lateral and rotation stiffnesses of the pier bent foundation.
An equivalent linear iterative procedure was used to determine the foundation stiffness. Three loading cases were used in the study. The first case was a lateral load applied to the longitudinal direction of the foundation and the other two cases were lateral load and couple loading applied to the transverse direction of the foundation. Six lateral load levels and five couple levels were used in the calculation.
The lateral load versus displacement curves in both the longitudinal and the transverse direction showed the nonlinear behavior of the foundation due to increasing the loads. The soil above the pile cap had the significant influence on the deformation and the stiffness of the foundation in the longitudinal direction. The deformation of the foundation model without the soil above the pile cap was larger than the model with the soil above the pile cap. Based on the evaluation of the foundation stiffnesses, simplified foundation models are proposed for the earthquake analysis of the bridge model system in the longitudinal and transverse direction (Abstract by authors).