Title: Practical Calculus Methods for Flexural Response of Shallow Beam Foundation
Author(s): Giuseppe Campione, Francesco Cannella, and Maria Zizzo
Publication: Structural Journal
Appears on pages(s): 45-54
Keywords: plasticized zone; rigid-plastic behavior; shallow foundation; ultimate load
In this work, the behavior of reinforced concrete (RC) beams on a soil foundation subjected to concentrated vertical loads and bending moments in both the elastic and the plastic phases was examined. Some of the simplified methods for hand calculations available in the literature, which are useful for the preliminary design of the foundation structures, are reviewed. A simplified plastic calculation method was developed. The method examines the limit cases of partial or full plasticization of soil and the formation of plastic hinges in the beam with elastic or plasticized soil. The proposed method showed good agreement with others in the literature. The purpose of the proposed method was to provide a simple calculation tool useful for calculating the foundation’s bearing capacity and for verifying the overstrength of the soil-foundation complex compared to that of the beam alone. The method highlights that the plastic resources of the soil-foundation complex depend not only on the characteristics of the soil such as cohesion, friction angle, and constant back soil, but also on the geometrical and mechanical characteristics of the foundation beam and on the characteristics of the vertical load (intensity, eccentricity). It was also shown that the maximum ratio of longitudinal steel bars should be determined to ensure the strength hierarchy with the plasticization of RC beams before soil plasticization.