Geosynthetically Confined Soil (GCS) Research and Case Histories.

1. 40+ YEARS AND 25,000,000
FHWA, UNIVERSITY AND DOT RESEARCH

3. 2nd
REINFORCED
EARTH tm
WALL
IN THE U. S.
Barrett
and Ruckman

4. FULL TIME
INSTRUMENTATION
TEAM

5. 1st FULL
HEIGHT
PANEL
REINFORCED
EARTH
WALL
Barrett
Ruckman

6. First Major U. S. Gabion Wall
Barrett 1969

7. U. S. Forest Service
First use of geosynthetics
----to stabilize logging
roads

8. U. S. Forest Service John Steward
First USA Fabric Wall

9. U. S. Forest Service
First Use of Wood Chips
As Backfill

10. Colorado DOT
GCS® Demo
Barrett and Ruckman
1981

11. LARGEST
GEOSYNTHETICALLY
CONFINED SOIL (GCS®)
DEMO WALL
Colorado DOT 1982
BARRETT, RUCKMAN
AND BELL

12. MASSIVE SURCHARGE LOADING

13. Long Term Durability Research
These fabrics will last hundreds of years

14. FHWA GRS/GCS® Research
Adams, Wu, Barrett, Ruckman
1996

15. Direct
Shear
Test Box
Interface
Friction
Testing
For
Geosynthetics
And a
Variety of
Backfills
Sand
Clay
Wood Chips
Shredded Tires
Glass

16. CDOT/UC/D
Full Scale
GCS®
Retaining
Wall Test
Frame
Barrett,
Wu,
Ruckman

17. FHWA GRS/GCS® BRIDGE PIER
EXCEEDS 10 TONS PER SQUARE FOOT
BEARING CAPACITY
NCHRP REPORT 556
FHWA
THFRC
RESEARCH
CENTER

18. Japanese
Demo
For
Minimum
Fabric
Width
(2 feet)

19. TECHNOLOGY EVOLUTION
Wall Type
External Internal
Tieback Soil Nails MSE GCS®
metallic geosynthetic
Strips Wire Grids 0.8m 0.6m 0.4m 0.2m
Increased Reinforcement Frequency

20. Weak Reinforcement?
How about bedsheets and cheesecloth?
3372 lbs/ft2
Tult = 20 lbs/in Photo courtesy of M. Adams

21. Spacing Controls Performance
….Not Strength of the Inclusion
BASED ON
NCHRP REPORT 556

22. THE
OPTIMUM
DESIGN…1.2.3.
1. CMU
2. GRANULAR
BACKFILL
3. FABRIC

23. GCS® MSE
1.Composite Structure 1.Reinforced Soil Structure
2.Internally stable 2.Quasi-tieback
3.Friction Connections 3.Pin Connections
4.Lightweight Inclusions 4.Strong reinforcement
5.Close spacing 5.Wide Spacing
6.High Safety Factor 6. 2-10% Failure Rate

24. Thrust on Facing Elements
Assuming a “yielding” facing, the loading is negligible.
1/3 σh Reinforcement
S 7/10 S Granular Backfill
3/10 S (φ = 34°)
2/3 σh (γ = 125 lbs/ft2)
σh = γ S Ka = γ S tan2 (45°- 34°/2) = 125 S (0.283) = 35.4 S (lbs/ft2)
F = 2/3 σh (7/10 S) + 5/6 σh (3/10 S)
= 43/60 σh S
= 25.4 S2 lbs/ft
Wu, McMullen, and Ruckman

25. COMPACTION
AT THE FACE
IS ROUTINE WITH GCS®
A LIFT OF
GRAVEL
BEHIND THE
FACING BLOCKS
IS
UNWARRANTED
CONCRETE
FOOTERS
ARE
COUNTER-
PRODUCTIVE Turkey, 1995
Barrett,
Ruckman,
Guler

26. 55 FOOT HIGH GCS® WALL
BUILT BY COUNTY FORCES
AND SUMMER HELP
Barrett and Ruckman Presented with
1998 IFAI International Design Award
Mike Adams
FHWA

27. • HALF THE
COST
OF THE BRIDGE
SCHEDULED
FOR THIS
CROSSING AND
• HALF THE
TIME

28. SAVINGS COMPARED TO PILING
$600,000 AND HALF THE TIME

29. GEOSYNTHETICALLY CONFINED SOIL (GCS®)
NCDOT EMPLOYEES
CONSTRUCTING GCS® WALL
1. 2. 3.

30. VDOT
EMPLOYEES
BUILDING
A GRS®
RETAINING
WALL

31. INDIANA DOT GCS®

33. CITY
EMPLOYEES’
FIRST GCS®
PROJECT
1. CMU’S
2. BACKFILL
3. FABRIC

34. Istanbul GCS® Wall
Barrett, Ruckman,
Guler

35. 2008
MEXICO’S
FIRST
GCS®
WALL

36. Note there is no
minimum width -- and
note the light weight
2008 Inclusions for the GCS®
NEW
ZEALAND
GCS®
VARIATION
WITH
SHOTRODS™
(LAUNCHED
NAILS™)
http://www.hiwaystab.co.nz/

37. GCS® IN JAMAICA

38. 2008
MEXICO’S
FIRST
GCS®
WALL

39. 2007
CANADA’S
FIRST
GCS®
WALL

40. NATIVE STONE CAN BE USED FOR FACING
MORTAR IS NOT REQUIRED

41. A 275,000 POUND LOCOMOTIVE ON A GCS® WALL

43. DRY STACKED GCS® ROCK WALL ON
SOIL NAILED FOUNDATION

47. BRIDGES ON GRS/GCS® ABUTMENTS
DEFIANCE COUNTY, OHIO
DESIGNED WITH CRITERIA PROVIDED IN
NCHRP REPORT 556

48. CDOT GCS® BRIDGE ABUTMENT AND PIER DEMONSTRATION

50. DEFIANCE
COUNTY
OHIO
GRS/GCS®
ABUTMENTS

51. BRIDGES ON GCS® COST LESS, LAST LONGER, CAN
BE CONSTUCTED IN A DAY, AND NO “BUMP”

56. 2007
CANADIAN
GCS®
ABUTMENTS
CALVIN VANBUSIRK
TERRATECH

57. 191 FOOT LONG SINGLE SPAN ON GCS®
BIG SKY, MONTANA

58. JAPANESE NEGATIVE BATTER DEMONSTRATION
60 DEGREES NEGATIVE AND NO FACING
GCS® IS INDEED AN EXCEPTIONAL TECHNOLOGY

59. NEGATIVE
BATTER
SAFE
AND
USEFUL

61. GCS ROCKFALL
PROTECTION
ON I-70
This Wall
Provides a
30 Foot Wide
Bench Above
Look at the next
Photo…….

62. 15 million
foot pounds onto this
GCS Wall!!!

63. THE DAMAGE WAS EASILY REPAIRED

64. A GCS® wall or abutment can withstand
the most severe credible earthquake.
Dr. J.T.H. Wu and NCHRP 12-59