Impact of Toe Resistance in Reinforced Masonry Block Walls: Design Dilemma
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 138, Issue 2
Abstract
Reinforced masonry block retaining walls are comprised of a narrow column of stacked blocks at their exposed end. This column is placed on a nonstructural leveling pad to facilitate the placement of facing units. Theoretically, this column can generate very large toe resistance to sliding. A recent publication indicates that an accepted design methodology implicitly counts on this resistance in assessing the reinforcement load. Although not calculated in this design, it unconditionally considers that over 60% of the resultant horizontal force in a 12-m-high wall is carried by the toe, which is made up of 0.3-m-deep blocks. This paper elucidates this issue by explicitly identifying the magnitude of toe resistance and critically reviews whether such high resistance is universally suitable for design. It shows that high toe resistance may not be feasible for most foundation soils. The high impact of toe resistance on the reinforcement force poses a design dilemma as to the reliability of this resistance, even if attainable. Practically, the leveling pad is not intended to serve as a critical structural element and thus should not be relied on for maintaining the toe resistance in long-term design. Economically, ignoring the toe resistance has little impact on the overall cost.
Get full access to this article
View all available purchase options and get full access to this article.
Acknowledgments
The detailed and constructive comments by the reviewers are highly appreciated.
References
AASHTO. (2007). LRFD bridge design specifications, 4th Ed., Washington, DC.
Bathurst, R. J., Miyata, Y., Nernheim, A., and Allen, A. M. (2008). “Refinement of -stiffness method for geosynthetic reinforced soil walls.” Geosynth. Int., 15(4), 269–295.
Dawson, E. M., Roth, W. H., and Drescher, A. (1999). “Slope stability analysis by strength reduction.” Geotechnique, 49(6), 835–840.
Ehrlich, M., and Becker, L. D. B. (2010). “Reinforced soil wall measurements and predictions.” Proc., 9th Int. Conf. on Geosynthetics: Geosynthetics for a challenging world, E. M. Palmeira, D. M. Vidal, A. S. J. F. Sayao, and M. Ehrlich, eds., Vol. 1, IGS Brasil and ABMS, Brazil, 547–559.
Federal Highway Association (FHWA). (1997). “Mechanically stabilized earth walls and reinforced soil slopes, design and construction guidelines.” V. Elias and B. R. Christopher, eds., FHWA-SA-96-071, Washington, DC.
Federal Highway Association (FHWA). (2001). “Mechanically stabilized earth walls and reinforced soil slopes, design and construction.” V. Elias, B. R. Christopher, and R. R. Berg, eds., FHWA-NHI-00-043, Washington, DC.
Federal Highway Association (FHWA). (2009). “Design and construction of mechanically stabilized earth walls and reinforced soil slopes.” R. R. Berg, B. R. Christopher, and N. C. Samtani, eds., FHWA-NHI-10-024, Washington, DC.
Griffiths, D. V., and Lane, P. A. (1999). “Slope stability analysis by finite elements.” Geotechnique, 49(3), 387–403.
Hatami, K., and Bathurst, R. J. (2005). “Development and verification of a numerical model for the analysis of geosynthetic-reinforced soil segmental walls under working stress conditions.” Can. Geotech. J., 42(4), 1066–1085.
Huang, B., Bathurst, R. J., Hatami, K., and Allen, T. M. (2010). “Influence of toe restraint on reinforced soil segmental walls.” Can. Geotech. J., 47(8), 885–904.
Leshchinsky, D. (2009). “On global equilibrium in design of geosynthetic reinforced walls.” J. Geotech. Geoenviron. Eng., 135(3), 309–315.
Leshchinsky, D., and Han, J. (2004). “Geosynthetic reinforced multitiered walls.” J. Geotech. Geoenviron. Eng., 130(12), 1225–1235.
Leshchinsky, D., Zhu, F., and Meehan, C. L. (2010). “Required unfactored strength of geosynthetic in reinforced earth structures.” J. Geotech. Geoenviron. Eng., 136(2), 281–289.
Ling, H. I., Mohri, Y., Leshchinsky, D., Burke, C., Matsushima, K., and Liu, H. (2005). “Large-scale shaking table tests on modular-block reinforced soil retaining walls.” J. Geotech. Geoenviron. Eng., 131(4), 465–476.
National Concrete Masonry Association (NCMA). (1993). NCMA segmental retaining wall design manual, 1st Ed., M. R. Simac, R. J. Bathurst, R. R. Berg, and S. E. Lothspeich, eds., Herndon, VA.
National Concrete Masonry Association (NCMA). (1997). Design manual for segmental retaining walls, 2nd Ed., J. G. Collin, ed., Herndon, VA.
National Concrete Masonry Association (NCMA). (2009). Design manual for segmental retaining walls, 3rd Ed., Herndon, VA.
Ugai, K., and Leshchinsky, D. (1995). “Three-dimensional limit equilibrium and finite element analysis: a comparison of results.” Soils Found., 35(4), 1–7.
Washington State Dept. of Transportation (WSDOT). (2010). Geotechnical design manual, Chapter 15, Olympia, WA.
Information & Authors
Information
Published In
Copyright
© 2012 American Society of Civil Engineers.
History
Received: Jan 27, 2011
Accepted: Jun 10, 2011
Published online: Jan 17, 2012
Published in print: Feb 1, 2012
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.