ASTM D7737/D7737M-15(2023)

Standard Test Method for Individual Geogrid Junction Strength

SIGNIFICANCE AND USE
5.1 This index test method is to be used to determine the strength of an individual junction in a geogrid product. The test is performed in isolation, while in service the junction is typically confined. Thus the results from this test method are not anticipated to be related to design performance.  
5.2 The value of junction strength can be used for manufacturing quality control, development of new products, or a general understanding of the in-isolation behavior of a particular geogrid’s junction (for example, in relation to handling during shipment and placement of the geogrid).  
5.3 This test method is applicable to geogrid products with essentially symmetrical orthogonal or non-orthogonal ribs, yarns, or straps, that is, geogrids which are composed of ribs, yarns, or straps that are entangled through weaving or knitting, welded, bonded, or formed through drawing.
SCOPE
1.1 This test method is an index test which provides a procedure for determining the strength of an individual geogrid junction, also called a node. The test is configured such that a single rib is pulled from its junction with a rib(s) transverse to the test direction to obtain the maximum force, or strength of the junction. The procedure allows for the use of two different clamps with the appropriate clamp selected to minimize the influence of the clamping mechanism on the specific type of geogrid to be tested.  
1.2 The values stated in either SI units or inch-pound units are to be regarded separately as standard. The values stated in each system are not necessarily exact equivalents; therefore, to ensure conformance with the standard, each system shall be used independently of the other, and values from the two systems shall not be combined.  
1.3 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.4 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.

General Information

• Status: Published
• Publication Date: 31-May-2023
• ICS: 59.080.70 - Geotextiles
• Technical Committee: D35 - Geosynthetics
• Drafting Committee: D35.01 - Mechanical Properties

Relations

• Refers: ASTM D4354-12(2020) - Standard Practice for Sampling of Geosynthetics and Rolled Erosion Control Products (RECPs) for Testing
• Effective Date: 01-May-2020

Standards Content (Sample)

This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: D7737/D7737M − 15 (Reapproved 2023)
Standard Test Method for
1
Individual Geogrid Junction Strength
This standard is issued under the fixed designation D7737/D7737M; the number immediately following the designation indicates the
year of original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last
reapproval. A superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope D5262 Test Method for Determining the Unconfined Ten-
sion Creep and Creep Rupture Behavior of Planar Geo-
1.1 This test method is an index test which provides a
synthetics Used for Reinforcement Purposes
procedure for determining the strength of an individual geogrid
junction, also called a node. The test is configured such that a
3. Terminology
single rib is pulled from its junction with a rib(s) transverse to
3.1 Definitions: Definitions of other terms applying to this
the test direction to obtain the maximum force, or strength of
test method appear in Terminology D4439.
the junction. The procedure allows for the use of two different
3.1.1 atmosphere for testing geosynthetics, n—air main-
clamps with the appropriate clamp selected to minimize the
tained at a relative humidity of 50 to 70 % and a temperature
influence of the clamping mechanism on the specific type of
of 21 6 2 °C [70 6 4 °F].
geogrid to be tested.
3.1.2 breaking force, (F), n—the force at failure.
1.2 The values stated in either SI units or inch-pound units
are to be regarded separately as standard. The values stated in
3.1.3 geogrid, n—a geosynthetic formed by a regular net-
each system are not necessarily exact equivalents; therefore, to
work of integrally connected elements with apertures greater
ensure conformance with the standard, each system shall be
than 6.35 mm [0.25 in.] to allow interlocking with surrounding
used independently of the other, and values from the two soil, rock, earth, and other surrounding materials to primarily
systems shall not be combined.
function as reinforcement. D5262
1.3 This standard does not purport to address all of the 3.1.4 index test, n—a test procedure which may contain
safety concerns, if any, associated with its use. It is the
known bias, but which may be used to establish an order for a
responsibility of the user of this standard to establish appro- set of specimens with respect to the property of interest.
priate safety, health, and environmental practices and deter-
3.1.5 integral, adj—in geosynthetics, forming a necessary
mine the applicability of regulatory limitations prior to use.
part of the whole; a constituent.
1.4 This international standard was developed in accor-
3.1.6 junction, n—the point where geogrid ribs are intercon-
dance with internationally recognized principles on standard-
nected to provide structure and dimensional stability.
ization established in the Decision on Principles for the
3.1.7 rib, n—for geogrids, the continuous elements of a
Development of International Standards, Guides and Recom-
geogrid which are either in the machine or cross-machine
mendations issued by the World Trade Organization Technical
direction as manufactured.
Barriers to Trade (TBT) Committee.
3.1.8 rupture, n—for geogrids, the breaking or tearing apart
2. Referenced Documents
of ribs.
2
2.1 ASTM Standards:
4. Summary of Test Method
D4354 Practice for Sampling of Geosynthetics and Rolled
Erosion Control Products (RECPs) for Testing
4.1 This standard proposes a test method for performing
D4439 Terminology for Geosynthetics
tension tests on geogrid junctions. The procedure provides two
clamping techniques for the junction to be tested including:
Method A in which the clamps firmly grip the ribs transverse to
1
This test method is under the jurisdiction of ASTM Committee D35 on
the test direction on each side of the junction, and Method B in
Geosynthetics and is the direct responsibility of Subcommittee D35.01 on Mechani-
which the ribs transverse to the test direction are constrained in
cal Properties.
a slot, constraining rotation of the junction, while the rib in the
Current edition approved June 1, 2023. Published June 2023. Originally
test direction passes through the slot without the junction
approved in 2011. Last previous edition approved in 2015 as D7737/D7737M – 15.
DOI: 10.1520/D7737_D7737M-15R23.
clamp applying confinement to the junction. The junction
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
clamping technique is selected for the specific type of geogrid
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
in order to minimize rotation and corres
...