Swell Potential Related to Building Performance

Forty structures constructed on a closed site located on the potentially expansive Beaumont Clay formation in Southeast Texas were evaluated for signs of structural distress. The observed distress was correlated to the mean swell potential, computed by common procedures involving soil index properties taken from boring information for the site, and only a weak relationship was found. Furthermore, structures situated entirely below the locally accepted zone of significant seasonal moisture change were found to experience approximately as much distress as those which had floor slabs and grade beams situated at the surface and had only their load bearing footings situated below the zone of seasonal moisture change. Stronger correlations were found between distress and variability of rainfall during and immediately after construction. However, the relatively low coefficients of correlation suggested that other factors not normally detected by widely spaced borings made for foundation design purposes may be important in the prediction of the degree of distress.