Levelness of Newly Constructed Posttensioned Slabs for Residential Structures
Publication: Journal of Performance of Constructed Facilities
Volume 19, Issue 1
Abstract
This paper presents an analysis of data from surface elevation surveys performed on 971 newly constructed posttensioned slabs-on-ground for single-family structures in California. The results of 1,368 manometer surveys were collected by the California Geotechnical Engineers Association (CGEA) and made available for this study. The parameters studied were maximum elevation differential, maximum elevation differential along the edges, maximum edge-to-interior differential, maximum local gradient, and local levelness number. In addition, data from 397 slabs surveyed both before tensioning and after tensioning/loading were analyzed. Results of the statistical analyses are presented in the form of histograms and cumulative frequency distribution curves, as well as in tabular form. The study showed that posttensioned slabs-on-ground for residential structures are not built level; they typically have some as-built elevation differentials and local gradients. If manometer surveys are made on newly constructed slabs, such as-built elevation differentials and surface gradients can be documented and distinguished from any long-term differentials or angular distortions that might occur because of postconstruction ground movement.
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Acknowledgments
The writers express their appreciation to the California Geotechnical Engineers Association for making this study possible by coordinating the data-collection phase and by partially funding the analysis phase. The writers would also like to thank the consulting firms that provided the slab survey data for this study, as well as Dr. Vera Berger, who assisted with the statistical analyses. The writers’ interpretation of the data and the professional opinions expressed herein are not necessarily endorsed by the California Geotechnical Engineers Association.
References
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Information & Authors
Information
Published In
Journal of Performance of Constructed Facilities
Volume 19 • Issue 1 • February 2005
Pages: 49 - 55
Copyright
© 2005 ASCE.
History
Received: May 19, 2003
Accepted: Mar 29, 2004
Published online: Feb 1, 2005
Published in print: Feb 2005
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