LRFD Calibration of the Ultimate Pullout Limit State for Geogrid Reinforced Soil Retaining Walls
Publication: International Journal of Geomechanics
Volume 12, Issue 4
Abstract
The results of load and resistance factor design (LRFD) calibration are reported for the pullout limit state in geogrid reinforced soil walls under self-weight loading and permanent uniform surcharge. Bias statistics are used to account for the prediction accuracy of the underlying deterministic models for load and pullout capacity and the random variability in the input parameters. The paper shows that the current AASHTO simplified method to calculate reinforcement loads under operational conditions is overly conservative leading to poor prediction accuracy of the underlying deterministic model used in LRFD calibration. Refinements to the load and default pullout capacity models in the AASHTO and Federal Highway Administration guidance documents are proposed. These models generate reasonable resistance factors using a load factor of 1.35 and give a consistent probability of pullout failure of 1%. A comparison with the allowable stress design (ASD) past practice shows that the operational factors of safety using a reliability-based LRFD approach give factors of safety greater than 1.5. Regardless of the design approach (ASD or LRFD), the analysis results demonstrate that the current empirical minimum reinforcement length criteria will likely control the design for pullout.
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Acknowledgments
Financial support for this study was provided by the Natural Sciences and Engineering Research Council (NSERC) of Canada, grants from the Department of National Defence (Canada), the Ministry of Transportation of Ontario, and the following U.S. State Departments of Transportation: Alaska, Arizona, California, Colorado, Idaho, Minnesota, New York, North Dakota, Oregon, Utah, Washington, and Wyoming.
References
AASHTO. (2002). Standard specifications for highway bridges, 17th Ed., AASHTO, Washington, DC.
AASHTO. (2010). LRFD bridge design specifications, 5th Ed., AASHTO, Washington, DC.
Allen, T. M. (2005). Development of geotechnical resistance factors and downdrag load factors for LRFD foundation strength limit state design, Publication No. FHWA-NHI-05-052, Federal Highway Administration, Washington, DC.
Allen, T. M., and Bathurst, R. J. (2002a). “Observed long-term performance of geosynthetic walls, and implications for design.” Geosynth. Int.GINTFD, 9(5–6), 567–606.
Allen, T. M., and Bathurst, R. J. (2002b). “Soil reinforcement loads in geosynthetic walls at working stress conditions.” Geosynth. Int.GINTFD, 9(5–6), 525–566.
Allen, T. M., Bathurst, R. J., and Berg, R. R. (2002). “Global level of safety and performance of geosynthetic walls: An historical perspective.” Geosynth. Int.GINTFD, 9(5–6), 395–450.
Allen, T. M., Bathurst, R. J., Holtz, R. D., Lee, W. F., and Walters, D. L. (2004). “A new working stress method for prediction of loads in steel reinforced soil walls.” J. Geotech. Geoenviron. Eng., 130(11), 1109–1120.JGGEFK
Allen, T. M., Bathurst, R. J., Holtz, R. D., Walters, D. L., and Lee, W. F. (2003). “A new working stress method for prediction of reinforcement loads in geosynthetic walls.” Can. Geotech. J.CGJOAH, 40(5), 976–994.
Allen, T. M., Nowak, A. S., and Bathurst, R. J. (2005). “Calibration to determine load and resistance factors for geotechnical and structural design.” Circular E-C079, Transportation Research Board, National Research Council, Washington, DC.
Ang, A. H.-S., and Tang, W. H. (1975). Probability concepts in engineering planning and design, basic principles, Vol. 1, Wiley, New York.
Ang, A. H.-S., and Tang, W. H. (1984). Probability concepts in engineering planning and design, decision, risk and reliability, Vol. 2, Wiley, New York.
ASTM. (2001). Standard test method for measuring geosynthetic pullout resistance in soil, D6706-01, West Conshohocken, PA.
Bathurst, R. J., Allen, T. M., and Nowak, A. S. (2008a). “Calibration concepts for load and resistance factor design (LRFD) of reinforced soil walls.” Can. Geotech. J.CGJOAH, 45(10), 1377–1392.
Bathurst, R. J., Allen, T. M., and Walters, D. L. (2005). “Reinforcement loads in geosynthetic walls and the case for a new working stress design method.” Geotext. Geomembr., 23(4), 287–322.
Bathurst, R. J., Huang, B., and Allen, T. M. (2011a). “Interpretation of installation damage testing for reliability-based analysis and LRFD calibration.” Geotext. Geomembr., 29(3), 323–334.
Bathurst, R. J., Huang, B., and Allen, T. M. (2011b). “Load and resistance factor design (LRFD) calibration for steel grid reinforced soil walls.” Georisk: Assess. Manage. Risk Eng. Syst. Geohaz., 5(3–4), 218–228.
Bathurst, R. J., Huang, B., and Allen, T. M. (2012). “Interpretation of laboratory creep testing for reliability-based analysis and load and resistance factor design (LRFD) calibration.” Geosynth. Int.GINTFD, 19(1), 39–53.
Bathurst, R. J., Miyata, Y., and Allen, T. M. (2010). “Facing displacements in geosynthetic reinforced soil walls.” Proc., Earth Retention Conf. 3 (ER2010), ASCE Geo-Institute, Bellevue, WA, August 1–4, ASCE, Reston, VA, 442–459.
Bathurst, R. J., Miyata, Y., and Konami, T. (2011c). “Limit states design calibration for internal stability of multi-anchor walls.” Soils Found., 51(6), 1051–1064.SOIFBE
Bathurst, R. J., Miyata, Y., Nernheim, A., and Allen, T. M. (2008b). “Refinement of -stiffness method for geosynthetic reinforced soil walls.” Geosynth. Int.GINTFD, 15(4), 269–295.
Bathurst, R. J., Nernheim, A., and Allen, T. M. (2009). “Predicted loads in steel reinforced soil walls using the AASHTO simplified method.” J. Geotech. Geoenviron. Eng., 135(2), 177–184.JGGEFK
Becker, D. E. (1996a). “Eighteenth Canadian Geotechnical Colloquium: Limit states design for foundations. Part I. An overview of the foundation design process.” Can. Geotech. J.CGJOAH, 33(6), 956–983.
Becker, D. E. (1996b). “Eighteenth Canadian Geotechnical Colloquium: Limit states design for foundations. Part II. Development for the national building code of Canada.” Can. Geotech. J.CGJOAH, 33(6), 984–1007.
Benjamin, J. R., and Cornell, C. A. (1970). Probability, statistics, and decision for civil engineers, McGraw-Hill, New York.
Berg, R. R., Christopher, B. R., and Samtani, N. C. (2009). “Design of mechanically stabilized earth walls and reinforced soil slopes—volume 1.” Rep. No. FHWA-NHI-10-024, Federal Highway Administration, Washington, DC.
British Standards Institution (BSI). (2010). “Code of practice for strengthened/reinforced soil and other fills.” BS 8006, BSI, Milton Keynes, U.K.
Canadian Standards Association (CSA). (2006). “Canadian highway bridge design code.” CSA Standard S6-06, CSA, Toronto.
Harr, M. E. (1987). Reliability-based design in civil engineering, McGraw-Hill, New York.
Huang, B., and Bathurst, R. J. (2009). “Evaluation of soil-geogrid pullout models using a statistical approach.” Geotech. Test. J.GTJODJ, 32(6), 489–504.
Huang, B., Bathurst, R. J., and Allen, T. M. (2012). “Load and resistance factor design (LRFD) calibration for steel strip reinforced soil walls.” J. Geotech. Geoenviron. Eng., (Nov. 17, 2011).JGGEFK
Kongkitkul, W., Tatsuoka, F., Hirakawa, D., Sugimoto, T., Kawahata, S., and Ito, M. (2010). “Time histories of tensile force in geogrid arranged in two full-scale high walls.” Geosynth. Int.GINTFD, 17(1), 12–33.
Kulhawy, F. H., and Phoon, K.-K. (2002). “Observations on geotechnical reliability-based design development in North America.” Foundation design codes and soil investigation in view of international harmonization and performance based design, Honjo, Y., Kusakabe, O., Matsui, K., Kouda, M. and Pokharel, G., eds., Balkema, Lisse, Netherlands, 31–48.
Kulicki, J. M., Prucz, Z., Clancy, C. M., Mertz, D. R., and Nowak, A. S. (2007). “Updating the calibration report for AASHTO LRFD code.” Final Rep. NCHRP 20-07/186, Transportation Research Board, Washington, DC.
Miyata, Y., and Bathurst, R. J. (2007a). “Development of the -stiffness method for geosynthetic reinforced soil walls constructed with soils.” Can. Geotech. J.CGJOAH, 44(12), 1391–1416.
Miyata, Y., and Bathurst, R. J. (2007b). “Evaluation of -stiffness method for vertical geosynthetic reinforced granular soil walls in Japan.” Soils Found., 47(2), 319–335.SOIFBE
Nowak, A. S. (1999). “Calibration of LRFD bridge design code.” NCHRP Rep. 368, National Cooperative Highway Research Program, Transportation Research Board, Washington, DC.
Nowak, A. S., and Collins, K. R. (2000). Reliability of structures, McGraw-Hill, New York.
Paikowsky, S. G. (2004). “Load and resistance factor design (LRFD) for deep foundations.” NCHRP Rep. 507, National Cooperative Highway Research Program, Transportation Research Board, Washington, DC.
Phoon, K.-K., and Kulhawy, F. H. (2003). “Evaluation of model uncertainties for reliability-based foundation design.” Applications of statistics and probability in civil engineering, Der Kiureghian, A., Madanat, S. and Pestana, J. M., eds., Millpress, Rotterdam, Netherlands, 1351–1356.
Tatsuoka, F., Hirakawa, D., Shinoda, M., Kongkitkul, W., and Uchimura, T. (2004). “An old but new issue: Viscous properties of polymer geosynthetic reinforcement and geosynthetic-reinforced soil structures.” Proc., 3rd Asian Regional Conf. on Geosynthetics (GeoAsia 2004), Lecture, Keynote, Shim, J. B., Yoo, C. and Jeon, H.-Y., eds., Korean Geosynthetics Society, Seoul, Korea, 29–77.
Walters, D. L., Allen, T. M., and Bathurst, R. J. (2002). “Conversion of geosynthetic strain to load using reinforcement stiffness.” Geosynth. Int.GINTFD, 9(5–6), 483–523.
Information & Authors
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Published In
International Journal of Geomechanics
Volume 12 • Issue 4 • August 2012
Pages: 399 - 413
Copyright
© 2012. American Society of Civil Engineers.
History
Received: Aug 4, 2011
Accepted: Apr 4, 2012
Published online: Apr 11, 2012
Published in print: Aug 1, 2012
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