What is GRS? Geosynthetically Reinforced Soil

"The soil mass of GRS systems is reinforced in layers with a polymeric geosynthetic (e.g., geogrids or geotextiles), and the layered reinforcement is attached to facing elements that constitute the outer wall. Because the facing elements are commonly composed of articulated units that are not rigidly attached to each other, the wall is deemed flexible. Various materials, including natural rock, concrete block, gabion, or timber, may be used for the flexible facing. GRS structures are more forgiving to differential foundation settlement thus minimizing the bump that commonly develops between the roadway and bridge. GRS structures are more adaptable to low quality backfill, easier to construct, and more economical than their conventional counterparts.  GRS structures can be put into service quickly, can be built by maintenance personnel, and are especially well suited to projects constructed in areas that are difficult to access with heavy equipment. GRS structures are an economical alternative for temporary structures, because of their easy demolition and the recyclable nature of their components, and for emergency work, because of reduced lead time and lower equipment requirements."

An excerpt from the forward of  NCHRP Report 556 Design and Construction Guidelines for Geosynthetic-Reinforced Soil Bridge Abutments with a Flexible Facing

 

Link to FHWA Youtube video

How is Defiance County using it?

For culvert headwalls and wingwalls.

 

For bridge abutments

Bowman Road -2005

As can be seen from the above photos, the beams actually sit on the fabric reinforced stone and there is no cast-in-place concrete in the structure

2006 Bridges                                     

2007 Bridges

2008 Bridges

2009 Bridges

2010 Bridges

2011 Bridges

 

Link to Defiance County recent bridge bids - See The Bend Road Bridge and Mulligans Bluff Bridge

 

Link to FHWA Youtube video

Link to FHWA Interim Implementation Guide- New 2011

For more information contact Warren Schlatter, Defiance County Engineer

or Mike Adams, FHWA

 

Links

FHWA's Turner Fairbank Highway Reasearch Center

FHWA's Every Day Counts - GRS-IBS

April 2011 FOCUS article

April 2006 FOCUS article

Design and Construction Guidelines for Geosynthetic-Reinforced Soil Bridge Abutments with a Flexible Facing an NCHRP document detailing design guidelines.

GRS Bridge Piers and Abutments FHWA Research Report

Public Roads Article - July/August 2000


Better Roads Article -February 2002

Erosion Control Article November 2003