Subgrade Reaction in Mat Foundation Design

In this article, subrade reaction, the most important variable in designing mat foundations, is reviewed in four landmark buildings in Houston, Ttexas. Broad concepts related to mat foundation analysis using the finite element method are described to explain the related salient soil-structure interaction concepts. A comprenehsive examination is also made of structural considerations in connection with mat foundation design. It is noted that use of a uniform coefficient of subgrade reaction to analyze and design mat foundations is an oversimplification of the soil response and will lead to wrong designs. The coefficient of subradge reaction may vary considerably across a mat. After analysis of bearing capacity, the discrete area method should be used to model mat-soil interaction.