EPI International Journal of Engineering
Volume 2, Number 2, August 2019, pp. 109-115
DOI: 10.25042/epi-ije.082019.04

pISSN 2615-5109
eISSN 2621-0541

Basic Study on Deformation Evaluation of Steel Wire Mesh for
Rational Gabion Structure Design
Hiroshi Nakazawaa,*, Tsuyoshi Nishib, Hiroyuki Kuriharac, Daisuke Suetsugud, Tadashi HaraeaEarthquake Disaster Mitigation Research Division, National Research Institute for Earth Science and Disaster Resilience. Email:nakazawa@bosai.go.jpbConstruction Project Consultants, INC. Email: t_nishi@cpcinc.co.jpcKurihara Kenzai Sangyou Co., Ltd. Email: h-kurihara@kurihara-kenzai.co.jpd
Department of Civil and Environmental Engineering Faculty of Engineering, University of Miyazaki. Email: suetsugu@cc.miyazaki-u.ac.jpeCenter for Disaster Prevention Promotion, Kochi University. Email: haratd@kochi-u.ac.jp

Abstract
Gabion structures are used in a variety of ways in Japan and around the world because they allow for the creation of simple structures at
highly reasonable construction costs and completion periods. Previous earthquake damage surveys have shown that, in many cases, gabion
structures did not collapse even though deformation was allowed, and have demonstrated that the wire mesh used in their construction has ahigh confinement effect on the stones filling the gabion. Despite this, gabions have not been actively utilized, nor have they been used toconstruct permanent structures in Japan because the design and construction of such structures are based on experience, and a standardized
design method has not been developed. Hence, in order to facilitate development a design method for gabion-based structures, we must firstgo back to the basics and establish a detailed explanation of the wire mesh deformation mechanism of such structures. In this study, we
performed tensile tests on wire meshes of different shapes in order to determine their strength and deformation characteristics and thenconducted numerical analyses using the results obtained. The tensile tests revealed that deformation characteristics differed depending on
the mesh shape and tensile direction. We also showed that the direction in which the tension acts and the mesh nodes are important, and thatthe test results could be reproduced via numerical analysis with the finite element method by using beam elements.
Keywords: Deformation characteristics; gabion; steel wire mes;, tensile tests

1. Background
The origins of gabions have been traced back as far as
circa 361-251 BC to the river embankments of the ancient
Dujiangyan irrigation system in Sichuan Province, China.
They began as cylindrical cages with a turtle-shell-shaped
mesh made of bamboo that were filled with quarry stones,
cobblestones, and such, as shown in Fig. 1. Today, their use
has spread all over the world, and the most commonly usedmaterial for the cage has changed to steel, which is moreadvantageous in many ways, including productivity [1].
The “Guidelines for Galvanized Steel Wire and Structureof Gabions” was established in Japan in April 1953 and theJapanese Industrial Standards for Galvanized Steel Wire
Gabions (JIS A 5513) was established in August 1954 to
improve and ensure the quality of gabion-based structures[2]. Despite this, there are currently no detailed design*Corresponding author. Tel.: +81-29-863-7308

guidelines such as those in concrete and other structures, andthere have been very few studies or practical design casesthat measure and evaluate the seismic resistance of gabionbased structures while taking into account their beneficial
properties such as high flexibility, trackability, andpermeability.
Therefore, the designs for gabion retaining walls andsimilar structures are still supported by road earthwork
concrete retaining wall design standards [3]. Hence, in thefields of agricultural and civil engineering works in Japan,
gabion-based structures remain a traditional construction
method, with almost no track record as semi-permanent
structures that make good use of their merits.
Several case examples have confirmed the benefits ofgabions such as the abovementioned high flexibility,
trackability, and permeability in previous earthquake
disasters. For example, after the Gorkha Earthquake thatstruck Nepal on April 25, 2015, a survey was conducted onroad embankment damage in flat areas and slope collapses

Tennodai 3-1,
Tsukuba, Ibaraki, Japan, 305-0006

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Figure 1. (a) Gabion-based embankment (Photo of a projectdescription board in Dujiangyan, Sichuan Province, China);(b) Recent Gabion-based structure

in mountainous areas, together with damage to roadretaining walls. The findings showed that while there wereSome cases of cracking in concrete retaining walls, thegabion retaining walls were only slightly deformed and did
not collapse [4]. According to the report, the gabion-based
structures were prevented from collapsing by theconfinement effect of steel wires, thereby demonstrating thatsuch structures are highly flexible and persistent.
Consequently, in order to take advantage of thisdurability and promote the broader use of gabions as adisaster prevention technique, the deformation mechanismof gabions must be determined, and standardized technology
for producing gabion-specific designs must be developed.
To accomplish these goals, a technological system
underpinned by a theoretical background must first be
established. In this study, tensile tests and replication
analyses performed on wire meshes were conducted toobtain basic data, after which a foundational study was
performed as a precursor to establishing a design method.

Figure 2. Breakdown of gabion structures along the Araniko Highway(revised from [5])Figure 3. Example of damage; (a) No major damage; (b) Partial
deformation; (c) Collapse

Figure 3 shows examples of the damage types observed.
Damage patterns were classified into three levels: nodamage, partial damage, and collapse, with around 80% of
those surveyed classified as partial or no damage. Thesefindings showed that the minimum road function had been
maintained in many cases, which demonstrates the durabilityof gabion-based retaining walls. Details of the field survey
have also been reported by Hara et al. [5].
2.2. Full-scale shake table test of gabion retaining wall

2. Significance of This Study Based on Previous Studies
Following the 2015 Nepal Gorkha Earthquake, a fieldsurvey and analysis of the causes of damage to gabion-based
retaining walls were conducted, after which shaking table
tests using full-scale models were performed. A descriptionof these tests is shown below, followed by a discussion of
the significance of this study.
2.1. Damage survey in Araniko Highway
Figure 2 shows the survey locations along the Araniko
Highway that were investigated after the Nepal Earthquake.
For the 115 gabion-based structures along the Araniko
Highway, the use, structure, surrounding conditions, gabion
dimensions and damage conditions, as well as the grid andwire dimensions, and the filling material quality anddimensions, were all surveyed. The results show that gabionbased structures were used as retaining walls at 56 locations(49%), as crash barriers at 22 locations (19%), for riverbank
and channel protection, etc. at 17 locations (15%), forerosion control dams at six locations (6%), and as retainment
barriers to prevent earth collapse, etc. at 13 locations (11%).
Many of the retaining wall gabion units appeared to havesizes that were adjusted to match field conditions, although
their widths, heights, and depths generally measure around100 cm, and many upright walls had heights of about 3 m.

A full-scale model experiment was conducted to verify
the seismic performance and dynamic behavior of gabionbased retaining walls during an earthquake. This has beenreported in detail by Nakazawa et al. [6]. Based on the fieldsurvey findings, an experiment was carried out on a retaining
wall model with a wall height of 3 m, using gabions withunit sizes of about 100 cm in width, height, and depth.
For the gabion wire mesh, a rhombus-shaped galvanizedproduct procurable in Japan, with a wire diameter of 3.2 mm
and a mesh 13 cm long based on the Japanese Industrial
Standards (JIS A 5513), was used because it was difficult toobtain the same products used in Nepal. Note that in Nepal,
wire diameters range from 3 to 5 mm, and meshes wereturtle-shell-shaped, square, or rhombus-shaped, with aminimum mesh size of 9 cm and a maximum of 18 cm.
In this set of experiments, tests were conducted using
three gabion retaining wall types shown as Cases 1 to 3, oneof which consisted of the vertically upright triple-stacked
gabion retaining wall common in Nepal and two which
involved newly proposed gabion structures [6]. As an
example here, the model specifications and test results forCase 1, which show the vertically upright triple stacks
common to Nepal, are shown in Figs. 4 to 6.
Shaking was performed by regulating the acceleration
amplitude of a 3 Hz sinusoidal wave in four stages: 65, 132,
203, and 257 gals. The dynamic behavior results showed that
there was a buildup of retaining wall horizontal
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displacement with increased shaking, and that cracks
appeared on the ground behind the retaining wall. After theshaking had completely ended, significant forward tilting of
the retaining wall and severe ground collapse behind the wall
were observed, as shown in Fig. 6.
In particular, there was pronounced deformation on thesecond layer of gabion and about 80 cm of horizontal
displacement at the top. However, the retaining wall did notcollapse even though it tilted about 18 degrees forward. This
type of retaining wall deformation was also commonly
observed in Nepal. This durability, which is also termed
persistence, is believed to be the reason why the wall did not
eventually collapse.

Figure 6. Horizontal displacement of gabion retaining wall front face [6]2.3. Purpose of this study

Figure 4. Cross-section of the full-scale gabion retaining wall
experiment (revised from [6])In the set of surveys and experiments discussed above,emphasis was placed on the filling material and method used
for stacking the gabions. The deformation of the gabion
retaining wall is thought to be dependent on the deformation
characteristics of the filling material and the confinement
effect of the wire mesh that restrains it. For example, in Fig.
7, it can be inferred that the confinement effect of the wire
mesh on the front side of the retaining wall is different fromthat on the rear side. That is, deformation on the front face isconsidered to be restrained by tensile resistance of the wire
mesh on the rear side when bending deformation occurs in
the flexible gabion retaining wall structure.
However, mesh shapes and their corresponding
deformation and strength characteristics have yet to bestudied. In a field trial construction case in Nepal [7], asshown in Fig. 8, the direction of the wire mesh in relation to
the assumed direction of retaining wall deformation had notbeen taken into account, and whether or not this may be adominant factor remains unclear.

Figure 5. Results of 3D measurements. (a) Before shake test. (b)After shaking at 203 Gals. (c) Residual deformation after final
shake test by 257 Gals. [6] The red lines show the original
position of the gabion wall

Figure 7. Schematic diagram of gabion-based retaining wall deformation

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Figure 8. Trial construction of a gabion-based retaining wall [7].
The direction of the turtle-shell-shaped wire mesh had not been
considered. (a) Mesh line is vertical. (b) Mesh line is horizontal

Figure 9. Wire meshes used in the tensile test. The panels consist of
200 mm × 200 mm galvanized wire with a wire diameter of 1.2 mm.
(a) Rhombus-shaped wire mesh. (b) Turtle-shell-shaped wire mesh

The rhombus-shaped wire mesh is common in Japan,
although in other countries such as Nepal, the turtle-shellshaped wire mesh is more widely used. Accordingly, to take
into consideration the loop shape and friction properties of
the wire mesh nodes, tensile tests were carried out using 200
mm × 200 mm wire mesh with two mesh shape types:rhombus and turtle shell, as shown in Fig. 9, in order todetermine their basic mechanical properties.
Moreover, to find out whether the test results can be
simulated, a replication analysis using the finite element
method (FEM) was performed and the results were
examined to determine whether it can be applied to thedesign of gabion-based retaining walls.
3. Tensile Test of Steel Wire Mesh
The tests were conducted in order to determine themechanical properties of the gabion wire mesh itself. Basedon the test results, a replication analysis using the FEM was
performed, as will be described in the following section.
Gabions have a simple structure consisting of a steel wire
mesh box filled with stones. However, the deformation
performance of single gabion units may differ depending on
the arrangement of the filling stones. A gabion-based
retaining wall is an assembly of gabion units, but the
deformation resistance performance of the structure as awhole can be increased by increasing the deformation
performance of individual gabion units.
When the gabion unit deforms, it is necessary to examine
what kind of wire mesh shape effectively provides theconfinement effect and the connection between the fillingstones and direction of the wire mesh. After completing thislevel of study, there will eventually be issues such as the
productivity of the most effective mesh types.
Next, in order to take the first step in improving thedeformation resistance performance of gabion structures asa whole, tensile tests were conducted to determine the basic

mechanical properties of gabion wire meshes according to
the mesh shape differences. Table 1 shows the test cases.
Basically, the objective of this test was to compare meshshapes and tensile direction, although differences in loading
rates were also investigated. The effect of the loading rate
was also checked because rearrangement, strength
development, etc. may possibly occur depending on the rate,even if the structure breaks partially during tensioning.
3.1. Specification and properties of steel wire mesh
The wire specimen used in the tensile test was a 1.2 mm
diameter galvanized steel product, from which panels were
fabricated with a mesh size of 200 mm × 200 mm, as shownin the lower part of Table 1. The tensile strength of the wire
was 350 to 380 N/mm2.
Using the test apparatus shown in Fig. 10, tensile tests
were carried out after running bolts through the edges of thewire mesh and fixing them in place. Note that due to thedifference in shapes between the rhombus and turtle shellmeshes, the number of bolts secured at the edges depends onthe mesh shape and could not be standardized. In this paper,
the test results were evaluated by comparing the tensile
behavior with respect to the relationship between the applied
tensile force T (kN) and the stroke of the testing apparatus.
In principle, the rate of tensioning used was 40 mm/min
using displacement control. For Case 1, the test was also
conducted at 10 mm/min in order to investigate thedependence on the loading rate.
Table 1. Tensile test cases. The  indicates bolt fixing positions
Case1 (a)Case1 (b)Case2 (a)Case3 (b)Lateral direction

Longitudinal
direction

Lateral direction

Longitudinal
direction

Rhombus shape steel wire mesh

Turtle shell steel wire mesh

Figure 10. Test apparatus

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Figure 11. Results of tensile tests

test results from a tensioning rate of 40 mm/min are
discussed in this paper.
Looking at Case 1 with a rhombus shape, we see that theload-displacement relationship did not change regardless ofthe direction of the wire mesh. However, Case 1(a) carries amore significant portion of the tensile force at the meshnodes than (b), so the tensile load developed early and theedges ruptured significantly, thus causing the peak value tobe small. Although both of these cases showed a dramatic
decrease in tensile force after peaking, it can be seen
afterward that the nodes that did not rupture cycled between
tensile loading and rupture until reaching their ultimate state.
As a whole, their post-test deformation characteristics did
not appear to be significantly different from each other, as
shown in Fig. 12.
In contrast, for Case 2 with the turtle-shell-shaped wire
mesh, it can be seen that the pattern of the load-displacement
relationship is completely different depending on the tensile
direction. For (b), in which the twists are parallel to thetensile direction, it can be seen that the tensile loading
developed at the smallest level of displacement. In this case,the mechanism does not involve taking up the tensile force
at the nodes as in Case 1, and the deformation does not seemto have loosened the twists, thereby suggesting that friction
at the twists is the dominant factor.
For (a), the twists are perpendicular to the tensile
direction. After the test, Figure 12 shows that the mesh shapedeformed into rectangles with the twists on the short side.
From the load-displacement relationship shown in Fig. 11, it
can be seen that although the effect of ruptures can beobserved, the tensile force did not peak as it gradually
increased with the increased displacement, even at
displacement levels where the test ended for other cases.
4. FEM Analysis for Tensile Tests of Steel Wire Mesh
When evaluating the stability of gabion-based retaining
walls, it is crucial to verify the confinement effect of the wire
mesh on the filling material. In the FEM analysis, areplication analysis of the tensile test results was performed
in order to determine the mechanical properties of the gabion
wire mesh. By comparing the deformed shape between thereplication analysis and the test results, the validity of the
FEM model could be checked and model improvements
were identified.
4.1. Analysis cases and modeling

Figure 12. Shapes before and after Tensile tests. (a) Rhombus shape (Case1(a)). (b) Rhombus shape (Case 1(b)). (c) Turtle shell shape (Case 2(a)).
(d) Turtle shell shape (Case 2(b)) in Table 1

3.2. Results of tensile tests
Figure 11 shows the test results for all cases, while Fig.
12 shows photos of post-testing wire mesh deformation. For
the effect of tensioning rates, which was tested in Cases 1(a)and (b), there were no differences in results observed
between 10 mm/min and 40 mm/min. Therefore, only the

Similar to the test cases shown in Table 1, the rhombusshaped and turtle-shell-shaped wire mesh diagrams areshown in Fig. 13. The member was considered as a linear
elastic body, and the load was applied to nodes at the upper
end while the lower end was fixed. Table 2 shows thephysical properties of the steel wire mesh material.
The nodes are a vital requirement in the modeling. The
rhombus shape was given uniform dimensions overall. In
contrast, because the turtle shell shape twisted parts have
two twined wires, the cross-sectional area and moment ofinertia were doubled.
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Table 2. Physical properties of the steel wire mesh model.
Diameter (mm)Cross section (m2)
Moment of inertia (m 4)Torsional moment (m4)Young’s modulus (kN/m2)
Poisson’s ratio
Unit weight (kN/m3)

1.2
1.131E-06
1.018E-13
2.036E-13
2.000E+08
0.30
77.0

In the replication analysis of the rhombus-shaped wire
mesh, joint springs were set at the intersecting points shownby the circle in Fig. 13. The spring properties were 1.0 × 107
kN/m in the y-direction and 1.0 × 103 kN/m in the xdirection. In other words, the joint was fixed when loaded in
the y direction, while slipping occurred when loaded in thex-direction.
For the turtle-shell-shaped mesh, when loading in the
direction of the mesh line, the lower end was fixed while theupper end was loaded at nine points with the load increasingby 1 kN increments in each of the 100 steps. When loadingin the direction perpendicular to the mesh line, the loading
points were set as eight points at the hexagonal vertices with
1 kN applied in 100 steps at each point same as the caseloading in the direction of the mesh line.
4.2. Results of FEM analysis

Figure 13. FEM models. (a) Rhombus shape. (b) Turtle shell shape

Figure 14 shows the deformation and axial force diagrams
based on the analysis for each case. Looking at the results on
the 50th step with 3.0 kN for Case 1(a) and (b) with therhombus-shaped mesh, it can be seen that loading in the xdirection has a slightly larger deformation, but the axial
force acting in the x-direction is larger. On the other hand,looking at the results of 37 steps with 2.96 kN acting in Case
2 with the turtle-shell-shaped mesh, we can see that the valueof the loads in (a) and (b) are almost the same, but theamount of deformation in (b) is much larger than in (a), andthe axial force is nearly double.
The above results show that for the turtle-shell-shaped
wire mesh, in particular, the highly anisotropic property, inwhich the deformation characteristics differ depending on
the direction of the acting tensile force, can also be expressedby numerical analysis.
4.3. Comparison of results between analysis and tensile tests
Similar to Figure 11, which summarizes the tensile test
results, Figure 15 shows a summary of the numericalanalysis results. Looking at the relationship shown in 15(a)between the displacement until 2 mm stroke and the tensile
force, we can see that the tendency for tensile resistance todevelop and the deformation performance for all the cases
are similar in both the test results and the analysis results. In
both, the deformation of (a) is larger than (b) in Case 1 as
well as in Case 2.
On the other hand, for the build-up after loading, it can beseen that, overall, the analysis results are larger than the test
results. This may conceivably be due to the fact that theanalysis used elastic analysis and that in the test, loosenessoccurred at the wire mesh crossings, which means that large
acting forces were not generated at the initial stage ofloading until those loose sections were closed and tensile
resistance was exerted.

Figure 14. FEM model

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Figure 15. Comparison FEM analysis and Tensile test results.

Next, looking at Fig. 15(b), it can be considered that
deformation performance in the tensile test results, from thedevelopment of tensile resistance until the start of partial
rupture or damage (indicated by ↔), is not significantly
different from those in the analysis results. In actual gabions,the filling material is granular and is not self-supporting, so
there are always tensile forces acting on the wire mesh at thesides of the structure. Therefore, the fact that deformation
performances are consistent between the analysis results andthe tensile test results for the section indicated (↔), in which
the stiffness has recovered in the tensile tests, may beconsidered to be a very significant finding of this study.
5. Conclusion
Gabions have advantages, such as high flexibility,
trackability, and permeability, which means that highly
disaster-resistant gabion-based structures that will notcollapse even when deformed can be built. However, adesign system has not yet been established because theirmechanisms remain unclarified. In this study, tensile tests
and replication analyses were conducted on wire meshes toobtain basic data, after which a foundational study was
performed as a precursor to establishing a design method.
From a series of test results, it was found that, regardlessof shape, wire meshes had strength anisotropy depending on
the tensile direction, and that both types of wire meshexamined in this study displayed tensile properties thatshowed stronger behavior in the direction of the mesh line.
For the turtle-shell-shaped wire mesh, friction at the twists
formed by winding the wire three times was found to be thedominant factor resisting tension, and the results showed thatits anisotropy is stronger than the rhombus-shaped wire
mesh, which is only hooked at the looping point.
On the other hand, in the replication numerical analyses
performed for the above tensile test results, because a certain
amount of displacement is needed until tensile resistance isexhibited for all of the test results, it is difficult to interpreta direct comparison with linear analysis, which has stiffness
from the initial stage. However, the relationship between theamount of displacement and tensile force showed that, in theelastic deformation range in which looseness in the wire
mesh has disappeared and stiffness has recovered in thetensile test, there was consistency between the test andanalysis results in each case. This suggests that the wire
mesh can be modeled and simulated until it becomesdamaged or ruptured.
The above findings provided an understanding of a partof the fundamental behavior of wire meshes. Moving
forward, a design method will have to be created through thedevelopment of a tensile strength evaluation method thatconsiders factors such as the wire mesh thickness, thenumber of nodes, and the amount of wire used. Additionally,
it will be necessary to develop a method for determining themesh direction for the wire mesh that considers the directionof external force and the deformation characteristics of thefilling material.
Acknowledgments
The authors express sincere appreciation to the support
by the Ohata-Foundation for the help in carrying out tensile
tests reported in this study.
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