GCS® WALL

Welcome to the Geosynthetically Confined Soil™ (GCS®) Website

About Us

Federally funded research shows that generic Geosynthetically Confined Soil (GCS®) structures can have bearing capacities and safety factors more than 10 times those of Mechanically Stabilized Earth (MSE) walls. NCHRP research demonstrated that GRS/GCS® walls and abutments can withstand any credible earthquake. State of the art GCS® technology translates into better, safer, quicker, easier and cheaper retaining walls, bridge abutments, box culverts, foundations, rockfall barriers, avalanche and debris flow deflectors, and more. Facing options include natural vegetation, wire mesh, natural stone, concrete block, or sculpted shotcrete. You are the designer – use your imagination.

GCS® structures behave as GeoMonoliths or Unique Composites. Unique Composite behavior exceeds the sum of its components. As with concrete, which is a Unique Composite, testing is done after combining the elements. We erred in the 1970’s by attributing the stellar performance of “fabric walls” to the contribution of the two elements, fabric and soil as simple composite behavior where performance is a predictable sum of the two elements. We called this Mechanically Stabilized Earth (MSE).

We then set out to “improve” the design with stronger, stiffer elements. And with all this added cost, we had to open the spacing for economy of material cost and the illusion of economy in construction. That was as wrong as wrong gets, and we have had chaos since. MSE has a failure rate, and with the certainty that many standing MSE walls are just marginally stable.

The key to GCS® performance, as demonstrated in the very first “fabric walls” in the 70’s, is close (8 inch/200mm) spacing of geosynthetic sheets in compacted granular backfill. These inclusions provide measureable confining effects in granular backfilll up to about four inches (100mm) from each sheet. Proximal confinement induces interparticle failure modes as with concrete and bedrock, and explains why Unique Composite GCS® structures even with the lightest fabrics can be designed to withstand loads over 20 tons per square foot (2.2 MPa). Simple composite, quasi-tieback MSE structures rely on intraparticle shear and can fail under self weight.

The world of opportunity in the true science of GeoMonlithic behavior is lost on our generation and probably the next. Our professors, engineers and associations have yet to recognize the grievous error of our day one decision to use Rankine methods to describe this Unique Composite or GeoMonolithic behavior. The world would be a different place had we understood in the 1970’s to test after construction….we would have recognized and quantified the non linear relationships of spacing. We would not have thrown the light, inexpensive fabrics under the bus in favor of wide spaced grids.

Herein are reports, papers and essays that add illumination to these topics. It is our goal, our hope, that this site will provide insight and incentive to our next generation of engineers to escape our current bondage to vendors, AASHTO, FHWA, NCMA, peer review, risk aversity and all the related trappings whose goal is immortalizing existing practice. Real engineering is fun. Just ask me and Al. One of the unexpected pleasures is finding out how little the establishment really knows. You will be disappointed to find how low the confining fence around your corral really is. It is an easy step out.

I am always available to comment, assist, even visit sites at no cost.

Bob Barrett
Participant in MSE development and Co-Founder of GCS® Wall Technology

ESSAYS
TYPE CLICK FILE NAME TO VIEW ESSAYS FILE SIZE
PDF logo GCS® GeoMonolith Theory, Design and Construction | PDF 191kb
PDF logo Geomonolith APPENDIX 1 Revisting Research | PDF 805kb
PDF logo Geomonolith APPENDIX 2 History of GCS® Research | PDF 414kb
PDF logo Geomonolith APPENDIX 3 Practical Design Considerations | PDF 158kb
PDF logo Geomonolith APPENDIX 4 Construction and Inspection | PDF 881kb
PDF logo Geomonolith APPENDIX 5 Bridges on GRS CGS Geomonoliths | PDF 1.39MB
PDF logo Geomonolith APPENDIX 6 Why we do what we do | PDF 154kb
PDF logo Letters to the Editor | PDF 104kb

PRESENTATIONS
TYPE CLICK FILE NAME TO VIEW PRESENTATION IN NEW WINDOW FILE SIZE
Flash logo Geosynthetically Confined Soil™ Presentation | Flash online
Flash logo Rockfall, Mudflow and Avalanche Protection with GCS® | Flash online
Flash logo Bob Holtz Symposium Presentation, GeoAmericas 2008, Cancun, Mexico online

TECHNICAL PAPERS
TYPE CLICK FILE NAME TO VIEW TECHNICAL PAPER FILE SIZE
PDF logo Adoption & implementation of GRS design concepts:
A consultant’s perspective
461kb
PDF logo MSE Retaining Wall Cost DOUBLES with AASHTO's new LRFD guidelines! 300kb
PDF logo Open Letter to FHWA and AASHTO on MSE and GCS® Walls 50kb
PDF logo Durability of Retaining Wall Facing Blocks 2MB



Free Workshops and Brownbags Presenters

This presentation/workshop is a summary of 40 years of research by the Colorado DOT, Federal Highway Administration, U. S. Forest Service and several universities in the U. S. and beyond. Topics will include the history of reinforced soil, the evolution of Mechanically Stabilized Earth (MSE) and the next generation of technologies based on the phenomenon of confined soil, Geosynthetically Confined Soil (GCS). Retaining walls to 300 feet high are possible. Bridges that last longer, cost less and are much faster to build are now mainstream in some parts of the U. S. These bridges and box culverts can be built in less than 24 hours in some cases. The presentation concludes with innovations in rockfall mitigation and landslide and erosion control - there are tools and technologies that can cut costs in half. These include the Soil Nail Launcher, SuperNails, SuperMicropiles, GCS retaining walls, GCS Rockfall Impact Barriers and more. Some discussion will be presented on newer technologies for rockfall mitigation and for scour remediation.

• Robert K. Barrett

Robert K Barrett
Robert K Barrett (right)

Bob is the founder and former owner of Soil Nail Launcher, Inc., a company that provides design/build solutions for landslides and erosion problems. Co-Founder of LandslideSolutions, Inc. of California and GeoStabilization, Inc. of Colorado. Past Chairman of NCHRP Project 12-59, charged with preparing Design and Construction Guidelines For Bridge Abutments on Geosynthetically Reinforced Soil. Past Chair of the TRB Committee on Geosynthetics, and the NCHRP project that developed proper closure methods for geotechnical borings. Recipient of 1991 Colorado Governor’s Award for creativity and innovation. Ruckman and Barrett were recipients of the IFAI International Design Award in 1997 for design and construction of a 55-foot-high GRS retaining wall. Co-Recipient of the international 2009 NOVA award from the Construction Innovation Forum for development of GCS bridge abutments. Partner Al Ruckman and Mr. Barrett have been awarded 7 patents, on retaining wall design, on rockfall fences, on earthquake resistant abutments on fiberglass nails, on shotcrete alternatives and on scour micropiles. Co-inventor of the Colorado Rockfall Simulation Program, a program that predicts the behavior of a rock in motion. We have presented GRS, landslide mitigation and rockfall technology transfer programs all over the U. S. and on all continents except Africa. Constructed GRS abutment and wall demonstration projects in several countries.

• Colby Barrett

Colby Barrett
Colby Barrett

Co-owner and President of SNL, Inc., Colby has worked for Bob and Al for over 10 years, managing projects throughout the continental United States, Puerto Rico, and Jamaica. Mr. Barrett studied Chemistry and Chemical Engineering at the University of California at Berkeley and Oxford University on an NROTC scholarship. He served as a Captain in the United States Marine Corps, leading both infantry and Scout/Sniper platoons throughout the Pacific Rim and the Middle East. Mr. Barrett holds Juris Doctor from the Yale Law School and is licensed in Colorado. He is currently wrapping up the requirements for his Professional Engineer License.

Contact US
Phone: (303) 909 2276
Email: asktheexperts@gcswall.com
GCS® Wall vs. MSE Wall:        

NOVA AWARD PRESENTATION, FLORIDA, NOV, 2009
Robert Barrett accepting the NOVA Award - 2009
Timothy Alter and Dr. Rasha Stino of the Construction Innovation Forum; Mike Adams, FHWA and Bob Barrett, recipients; Egon Larsen and Gregory Sizemore of the Construction Users Roundtable.

Other Examples of GCS® WallS & Abutments
OTHER USEFUL LINKS
Bedsheets as confining inclusions
Bedsheets as Confining Inclusions
Appendix 2


 

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