NCHRP 20-7
Proposed Research Needs Statement
Submitted by: Subcommittee on Bridges and Structures
AASHTO Technical Committee T15 Substructures and Retaining Walls
Mr. Jawdat Siddiqi, P.E., Chair
September 30, 2013
TITLE
Deformation of MSE Walls
BACKGROUND / NEEDS STATEMENT
Although there has been some research on the vertical and horizontal deformations of MSE
walls, currently there is little guidance describing how to predict MSE wall deformations either
during or post construction. In addition, there is very little research that has been done to predict
deformations of MSE wall supporting bridge loads. This work is not intended to evaluate
foundation settlement below the MSE wall but to look at the MSE fill compression and
associated lateral deflection due to its self-weight, dynamic construction effects (compaction)
and additional surcharges above the wall. This information is important in order to better
evaluate the serviceability of MSE walls.
From recent research it can be deduced that the MSE wall deformation is associated with many
variables including fill gradation and strength, reinforcement type and spacing (horizontal or
vertical), facing stiffness associated with facing type and connection strength, location of footing
relative to wall face, and abutment wall height. These variables may also have an influence on
the nominal strength limit state capacity of the abutment walls.
LITERATURE SEARCH SUMMARY
References:
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Adams, M., Nicks, J., Stabile, T., Wu, J., Schlatter, W. and Hartmann J. (2011a). Geosynthetic
Reinforced Soil Integrated Bridge System Interim Implementation Guide, Report No. FHWAHRT11-026, Federal Highway Administration, McLean, VA.
Adams, M., Nicks, J., Stabile, T., Wu, J., Schlatter, W. and Hartmann J. (2011b). Geosynthetic
Reinforced Soil Integrated Bridge System Synthesis Report, Report No. FHWA-HRT-11-027,
Federal Highway Administration, McLean, VA.
Al-Hussaini, M., and Perry, E. B., 1978, “Field Experiment of Reinforced Earth Wall,” Symposium
on Earth Reinforcement, Pittsburgh, ASCE, pp. 127-156.
Bastick, M., Schlosser, F., Segrestin, P., Amar, S., and Canepa, Y., 1993, “Experimental Reinforced
Earth Structure of Bouron Marlotte: Slender Wall and Abutment Test,” Proceedings International
Symposium on Soil Reinforcement, Full Scale Experiments of the 80’s, Paris, pp. 201-228.
Bathurst, R., Blatz, J., and Burger, M., 2003, “Performance of Instrumented Large-Scale
Unreinforced and Reinforced Embankments Loaded by a Strip Footing to Failure,” Canadian
Geotechnical Journal, Vol. 40, pp. 1067-1083.
Bathurst, R. J., Miyata, Y., and Allen, T.M., 2010, “Invited Keynote Paper, Facing Displacements in
Geosynthetic Reinforced Soil Walls,” Earth Retention Conference 3 (ER2010), ASCE Geo-Institute
Bellevue, WA, pp. 442-459.
Berg, R.R., Christopher, B.R. and Samtani, N.C., Design and Construction of Mechanically
Stabilized Earth Walls and Reinforced Soil Slopes, FHWA NHI-10-024 Vol I and NHI-10-025 Vol
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II, U.S. DOT, Federal Highway Administration, Washington, D.C., 2009, pp 306 (Vol I) and 378
(Vol II).
Christopher, B. R., Gill, S. A., Giroud, J.-P., Juran, I., Mitchell, J. K., Schlosser, F., and Dunnicliff, J.,
1990, Reinforced Soil Structures, Vol. 1 & 2 Design and Construction Guidelines, and Summary of
Research and Systems Information, FHWA Report FHWA-RD-89-043, 443 pp.
Damians, I.P., Bathurst, R.J., Josa, A., Lloret, A., Albuquerque, P.J.R. (2013), Vertical-Facing Loads
in Steel-Reinforced Soil Walls, ASCE Journal of Geotechnical and Geoenvironmental Engineering,
2013.139, P1419-1432.
Wu, J.T.H., Lee, K.Z.Z., Helwany, S.B. and Ketchart, K. (2006). Design and Construction Guidelines
for Geosynthetic-Reinforced Soil Bridge Abutments with a Flexible Facing, NCHRP Report 556,
Transportation Research Board, Washington, D.C.
RESEARCH OBJECTIVE
A study to investigate the impact of facing type, reinforcement strength, spacing and stiffness,
construction methods, and fill types on vertical and horizontal deformation of MSE walls is
needed to develop procedures to predict vertical and horizontal deformation of MSE walls
supporting concentrated bridge loads on shallow foundations. There are currently several papers
and reports published on the subject of load bearing MSE walls, as well as ongoing research,
though much of it is based on strength limit state design. The proposed research differs in that it
will explore the deformation, or service limit state, performance. The objective of this proposed
research is to develop a synthesis of existing and ongoing work to assess what is currently known
about MSE wall deformation when subjected to bridge abutment spread footing loads,
potentially provide provisional guidance on the deformation predictions for MSE walls, and to
highlight the research gaps to focus future work on the subject.
An outcome of the work would be to summarize the available data that could be used to develop
deformation prediction methods for MSE walls, and a potential improvement to guidance in
AASHTO Section 11.10 and in FHWA MSE Wall Design and Construction Manual.
WORK TASKS
Tasks anticipated in this project include the following:
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Synthesize past research on MSE wall deformations
Compile all available in-service and field test data for MSE wall deformations under various
loading conditions (e.g. traffic, bridge, seismic, etc.)
Summarize ongoing research and corresponding scopes
Based on past and ongoing research, propose future research to fill in research gaps
If sufficient information exists, develop recommendations for interim guidance for
serviceability evaluation of MSE walls.
URGENCY
Use of shallow foundations in lieu of deep foundations (piles and drilled shafts) to support
bridges on MSE wall abutments provides significant savings in construction cost, construction
time, and performance benefits to transportation agencies. Current guidance on the prediction of
vertical and horizontal deformation of MSE walls under footing loads is not specific, consisting
of only limited guidance based on experience.
FUNDING REQUESTED AND TIME REQUIRED
It is estimated that this research will take 9 months to complete and will require $100,000.
CONTACT PERSONS
Tony Allen
State Geotechnical Engineer
WSDOT
State Materials Laboratory
P.O. Box 47365
Olympia, WA 98504-7365
Phone: (360) 709-5450
allent@wsdot.wa.gov
Daniel Alzamora
Geotechnical Engineer
Federal Highway Administration
Office of Technical Services - Resource Center
12300 W. Dakota Ave.
Suite 340
Lakewood, CO 80228
Phone: (720) 963-3214
daniel.alzamora@dot.gov