Load-Displacement and Moment-Rotation Responses of Foundations Subjected to Moment Loading

Abstract

This study investigated the response of rigid surface foundations to moment loading based on nonlinear (hyperbolic) soil response. The response of a rectangular foundation on the surface of the ground was modeled as a nonlinear Winkler model. The nonlinear Winkler-based shallow foundation model was evaluated for its dependence on eccentricity of load, subgrade properties, etc. The key subgrade properties on which the proposed nonlinear model depends are the initial tangent subgrade modulus and ultimate bearing stress of the soil. The model was validated by comparing the predicted response of stress versus normalized displacement based on relevant soil properties with the response from the published data of field footing load tests. A parametric study quantified the effects of different parameters on the stress-displacement and moment-rotation responses of the foundation. The proposed analysis captured the inherent nonlinear deformations of the soil and the coupled nature of displacements and rotations of foundations subjected to eccentric loading. The predicted displacements compared well with the measured values.