TOP DOWN ROAD RECONSTRUCTION
Timeline and budget were critical for this job. The pavers were scheduled passing through this segment within 3 weeks of the pre construction meeting. In that time a design had to be developed, a contractor secured and construction complete to allow for asphalt.
Through the successes of the previous work on Highway 4 enough experience was gained to develop a GRS fill supported by rock anchors and micropiles into bedrock (Figure 15).
The system worked and the paving schedule was unaltered.
Figure 15. Lost Creek Typical Cross Section.
Sue Powells – MoTI Road Area Manager, Vince Trozzo MoTI Paving, Manager, Jonathan Tillie MoTI Operations Manager, Grant Lachmuth GeoStabilization International.
References
Adams1, M., et al., 2011. Geosynthetic Reinforced Soil Integrated Bridge System Interim Implementation Guide FHWA-HRT-11-026. Federal Highway Administration, U.S. Department of Transportation, Washington, D.C.
Adams2, M., et al., 2011. Geosynthetic Reinforced Soil Integrated Bridge System Synthesis Report FHWA-HRT-11-027. Federal Highway Administration, U.S. Department of Transportation, Washington, D.C.
Anderson D.G., Martin, G.R., Lam, I. And Wang, J.N. 2008. Seismic Analysis and Design of Retaining Walls, Buried Structures, Slopes, and Embankments, Project NCHRP 12- 70, National Cooperative Highway Research Program, NCHRP Report 611, Transportation Research Board, National Research Council, Washington, D.C.
Figure 16 - Lost Creek wall complete with new
asphalt ready for shotcrete.
Berg, Ryan R., Christopher, Barry R., Samtani, Naresh C., 2009, Design of Mechanically Stabilized Earth Walls and Reinforced Soil Slopes, FHWA-HRT-10-024 – Volume I. National Highway Institute, Federal Highway Administration, U.S. Department of Transportation, Washington, D.C.
Bullock, Peter, 2012, MSE vs. GRS Design Comparison and Implications, Masters of Engineering Thesis, University of Saskatchewan.
Dongwook, Kim., Rodrigo, Salgado. 2008. Limit States and Load Resistance Design of Slopes and Retaining Structures, FHWA/IN/JTRP-2008/5,SPR-2634, Joint Transportation Research Program Technical Report Series. Purdue University. Purdue e-Pubs.
Federal Highway Administration1, U.S. Department of Transportation, Every Day Counts Innovation Initiative, Retrieved April 2, 2012, from
http://www.fhwa.dot.gov/ everydaycounts/
Conclusions
Within a 12 month period 7 significant sites within the MoTI inventory had been mitigated with long term solutions and are now no longer maintenance issues. These repairs were extraordinarily efficient as the construction costs in terms of both time and money were repeatedly less than 50% of tradi- tional approaches.
Much of the savings were due to the compressed investiga- tion, design and construction sequence afforded by the design/ build approach. The technical requirements were attained with the philosophy that “many hands make light work”. The close spacing of smaller anchors provides a more uniform load- ing and redundancy, while the close spacing of the geosynthetic fabiric completely alters the soil mechanics of the retained fill.
Acknowledgements
The writers would like to acknowledge the contribution of a number of individuals to this project.
Bob Barrett GSI Founder, Colby Barrett GSI President, Nate Beard GSI Eastern Regional Director, Matt Birchmier, GSI Chief Engineer, John MacKay MoTI District Technician (retired), Cal Fradin MoTI Assistant District Technician (retired), Wayne Jentsch, MoTI Project Manager (retired),
Federal Highway Administration2, U.S. Department of Transportation, Every Day Counts Innovation Initiative/ GRS, Retrieved April 2, 2012, from
http://www.fhwa.dot. gov/everydaycounts/technology/grs_ibs/
Holtz, R.D. 2004. Geosynthethics R&D – The “Early”Days (1960’s to Circa 1985). In Proceedings from the 2004 Symposium Honouring the Research Achievements of Dr. Robert M. Koerner.
Hsuan, Y.G., et al (2008). Long-Term Performance and Lifetime Prediction of Geosynthetics. Proceedings of the 4th European Geosynthetics Conference, EuroGeo4 Keynote Paper, Edinburgh: 1-40.
Jones, C.J.F.P. 2002. Guide to Reinforced Fill Structures and Slope Design, Geoguide 6. Geotechnical Engineering Office, Civil Engineering Department, the Government of Hong Kong Special Adminstrative Region. 236 pages.
Szczepanik, Z., Milne, D., Hawkes, C., 2007. The Influences of End Effects on Unconfined Compressive Strength. Proceedings of the 1st Canada-US Rock Mechanics Symposium, Vancouver, Canada. 2007. pp 191-198.
www.aipg.org
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