STRUCTURAL DESIGN OF BURIED CIRCULAR CONDUITS
A PRACTICAL METHOD IS PROPOSED FOR THE STRUCTURAL DESIGN OF BURIED FLEXIBLE CONDUITS BASED ON THE ASSUMPTION THAT THE CONDUIT RING IS JUST ONE COMPONENT OF A SOIL-STRUCTURE INTERACTION SYSTEM. THE SOIL EXERTS PRESSURE ON THE FLEXIBLE CONDUIT, BUT IT ALSO CONTRIBUTES STRUCTURAL STRENGTH WHICH IS DETERMINED BY THE RELATIVE STIFFNESS OF THE SOIL AND CONDUIT RING. ACCORDING TO THIS APPROACH, THE RIGID CONDUIT IS SIMPLY A LIMITING CASE OF FLEXIBLE CONDUIT, AND MAY BE ANALYZED BY THE SAME METHOD. CRIPPLING FAILURE IS ANALYZED FOR THE IDEAL LIMITING CASE OF NONCOMPRESSIBLE SOIL, AND FOR COMPRESSIBLE SOIL. PRACTICAL STRUCTURAL DESIGN OF CIRCULAR CONDUITS IS BASED ON CONDUIT DEFORMATION WHICH FALLS INTO TWO AREAS FOR CONSIDERATION, WALL CRIPPLING AND RING DEFLECTION, WITH ADDITIONAL LIMITATIONS ON FLEXIBILITY FOR HANDLING AND PLACEMENT, ON BEDDING, POSSIBLY ON BLANKETING, ETC. CRIPPLING IS LIMITED BY A GIVEN FIGURE WHICH SHOWS THE RING-COMPRESSION STRENGTH AS A FUNCTION OF CONDUIT PROPERTIES AND THE SOIL-FRICTION ANGLE. THE RING COMPRESSION STRENGTH MUST BE REDUCED BY A SAFETY FACTOR. RING DEFLECTION FOR NONFLEXIBLE CONDUITS CAN BE ESTIMATED BY MODIFYING THE RING DEFLECTION FACTOR FOR A FLEXIBLE CONDUIT BY MEANS OR A GIVEN FIGURE. RING DEFLECTION IS QUICKLY AND CONSERVATIVELY ESTIMATED FOR FLEXIBLE CONDUITS BY THE CONSERVATIVE ASSUMPTION THAT THE RING DEFLECTION FACTOR IS EQUAL TO THE VERTICAL SOIL STRAIN FROM A CONSOLIDOMETER TEST. A FIGURE IS GIVEN FROM WHICH TO DETERMINE THE RING DEFLECTION FACTOR.
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Supplemental Notes:
- Paper sponsored by Committee on Buried Structures and presented at the 45th Annual Meeting. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
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Authors:
- Watkins, Reynold K
- Publication Date: 1966
Media Info
- Media Type: Digital/other
- Features: Appendices; Figures; Photos; References;
- Pagination: pp 1-16
- Monograph Title: Buried circular conduits and behavior of foundations
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Serial:
- Highway Research Record
- Issue Number: 145
- Publisher: Highway Research Board
Subject/Index Terms
- TRT Terms: Conduits; Consolidometers; Deflection tests; Fatigue tests; Flexible structures; Methodology; Soil structure; Stiffness; Structural design; Underground structures
- Old TRIS Terms: Conduit ring; Flexible conduits; Rigid conduits
- Subject Areas: Geotechnology; Highways; Hydraulics and Hydrology; Materials;
Filing Info
- Accession Number: 00204075
- Record Type: Publication
- Files: TRIS, TRB
- Created Date: Nov 18 1994 12:00AM