FINITE ELEMENT ANALYSIS OF DEEP BEAMS ON NONLINEAR ELASTIC FOUNDATIONS
A. A. Al- Azzawi, A. H. Mahdy and O. Sh. Farhan
Abstract
This research deals with the nonlinear material and geometric behaviors of reinforced concrete
deep beams resting on linear or nonlinear Winkler foundation. The finite elements through
ANSYS (Release-11, 2007) computer software are used. The reinforced concrete deep beam is
modeled using (SOLID 65) 8 node brick element and the soil is modeled using linear spring
(COMBIN 14) element or nonlinear spring (COMBIN39) element.
The results obtained from the present study are compared with available analytical or
experimental results. Good agreement is obtained with available results which also indicate the
efficiency of the finite element method used to model the problem. The difference in maximum
deflection between large and small deflections theory is found to be small. The maximum stress
is increased when the beam is resting on nonlinear Winkler foundation because of reduced
foundation stiffness.
Several important parameters are incorporated in the analysis - namely the vertical
subgrade reaction, mesh size, and compressive strength of concrete - to study their effects on
the beam behavior. The results demonstrate that the difference in maximum deflection between
the linear and nonlinear model of soil is about (2.5%).
