4 times stiffer than inner springs. Spring stiffness distributions bowles foundation analysis and design pdf in practice significantly underestimate positive bending moments.
Shear force diagrams are insensitive to the assumed spring stiffness distribution. Equations for determination of the appropriate spring stiffness distribution are proposed. Structural design of mat foundations of buildings is often done by performing static analysis of a slab resting on vertical uncoupled Winkler springs. It is already well established that the simplifying assumption of a uniform modulus of subgrade reaction throughout the mat foundation leads to inaccurate results that significantly underestimate the bending moments in the mat. This paper examines the spatial variation of the Winkler spring stiffness constants that is necessary for the mat-on-springs analysis to produce the same slab deflections and bending moment diagrams as finite element analysis that treats the soil as continuum.