Geosynthetics April/May 2020 - 25

Case study

Geosynthetic strip MSE wall
at Point Defiance Marina
By Paul C. Frankenberger and Robert Lozano

his article will focus on a geosynthetic strip mechanically stabilized earth
(MSE) wall case study using discrete geosynthetic strips with large precast
facing panels (Figure 1), an innovation of the original MSE invention. The system
is the Highway Innovative Technology Evaluation Center/National Transportation
Product Evaluation Program reviewed GeoMega Wall by The Reinforced Earth Co.
Modern-day MSE wall technology dates to the invention by Henri Vidal,
who first published his research in France in 1963. The Terre Armée-patented
system was galvanized ribbed steel soil reinforcement bolted to precast concrete
facing panels. The system has evolved over the past 40 years, is regularly in use
worldwide today, and is recognized as one of the top engineering achievements
of the 20th century. With its inception, using the typical MSE wall design methods, the maximum tensile force in the reinforcing strips is distributed at each
reinforcement layer into the number of reinforcements per unit of facing surface.
The reinforcement length is then checked behind the line of maximum tension
with respect to the available frictional capacity.
The first recorded use of polymeric strips as reinforcement for an MSE structure was a 4,844-square-foot (450-m2) wall located near Poitiers, France. The wall
was designed by Terre Armée in 1969 and constructed in 1970 using woven polyester strips (TAI 1982). Polymeric strips were fully introduced into the European
market in the mid-1970s. Instrumentation and full research followed; in 1977, a
full-scale and fully instrumented trial MSE wall was constructed at the Transport
and Roads Research Laboratory in Berkshire, United Kingdom, followed by a fully
functional instrumented bridge abutment constructed in Carmarthen Southern
Bypass in 1981. These two abutments were the first on a major road in the U.K. to
utilize polymeric reinforcement. Implementation and adoption of the geosynthetic
strips technology grew rapidly thereafter in Europe and the Middle East but was
practically unknown in North America until introduction to the market in 2005.
Applications along rivers, lakes and coastal areas are common for MSE walls. The
MSE technology offers aesthetically pleasing structure, long service life, considerable
savings in both material and construction costs, and flexibility to differential settlement and earthquake loading. In marine environments, an MSE wall provides desirable features such as resistance to severe loading conditions from flooding, rapid

PROJECT HIGHLIGHTS
GEOSYNTHETIC STRIP
MSE WALL
OWNER

Metro Parks Tacoma
LOCATION

Tacoma, Wash.
GENERAL CONTRACTOR

Atkinson Construction
MSE WALL SUBCONTRACTOR

KLB Construction
DESIGN ENGINEER

Jacobs Engineering
GEOSYNTHETICS PRODUCT

GeoStrap
GEOSYNTHETICS MANUFACTURER

The Reinforced Earth Co.

Paul Frankenberger, P.E., is business
development manager for The
Reinforced Earth Co. in Laguna
Hills, Calif.
Robert Lozano is senior geotechnical
engineer-corporate geosynthetic
specialist with The Reinforced Earth Co.
in Sterling, Va.
All figures courtesy of the authors unless otherwise noted

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Geosynthetics April/May 2020

Table of Contents for the Digital Edition of Geosynthetics April/May 2020