Performance and Design of Slab-on-Grade and Pier Foundation Systems: Theoretical Considerations and Practical Applications

The design of slab-on-grade and pier foundation systems requires knowledge of the site conditions including soil type, climatic conditions, and consideration of site anomalies. Case studies of poor performance, well-designed (in theory) slab-on-grade foundations indicate that site anomalies including subsurface perched water, pre-existing vegetation, pre-site development practices (including grading, drainage and surficial anomalies) control the designs. In this study, a heuristic approach is revealed for producing guidelines to avoid substantial site anomalies that cause unexpected and unwanted foundation movement and to provide better performing slab-on-grade and pier foundation systems. The heuristic approach will also be shown to comport with simple laws of thermodynamics including the consequence of the 2nd Law—the Principle of Increasing Entropy. Relative elevation surveys, unsaturated soil mechanics theory, geotechnical testing, and geo-electrical moisture material imaging resistivity surveys were used to evaluate the performance of the slab-on-grade and pier foundation systems. Exploration of the theoretical design of post-tensioned slab-on-grade foundations is provided including an analysis of the types of factors considered by most designers and a parametric analysis of slab performance under the assumed design conditions. Analysis of the design is performed using well-known industry methods including the Post-tensioning Institute's design methodology as well as finite element method analysis (FEM). The FEM program PLAXIS was used to model the soil-structure interaction mechanism. A new guideline that includes additional design considerations for a slab-on-grade and pier foundation system has been proposed based on theory and the case studies reviewed.

Language

  • English

Media Info

  • Media Type: Web
  • Pagination: pp 148-162
  • Monograph Title: The Art of Foundation Engineering Practice: GeoFlorida 2010

Subject/Index Terms

Filing Info

  • Accession Number: 01530586
  • Record Type: Publication
  • ISBN: 9780784410936
  • Files: TRIS, ASCE
  • Created Date: Jul 1 2014 3:01PM