Rebar Coupler Tensile Strength Test | Mechanical splice pull out test | Complete process explained

Material:
2.2.1 Couplers: The couplers are produced from steel complying with ASTM A576-06.
2.2.1.1
Identification: A sticker or stamp shall exist on coupler to identify its length, radius and
test number.
2.2.2 Steel Reinforcing Bars: The steel rebar must comply ASTM A615, Grade 60 or TS708, S420a -
B420C specifications. The performance of mechanical splices may be dependent on the rib geometry
of the steel reinforcing bar. The specified rib geometry of the test bar shall be provided by the supplier
and recorded with the test results.
Figure 1 - Rebar ID
“-“ sign between two ribs indicates S420a or B420C type.
Figure2 - Rebar ID
“- -“ sign between three ribs indicates S500a type.
3.0 TENSILE STRENGTH TEST
3.1 Objective:
The objective of the experiment is to investigate the behavior of Regnum Barcoup® mechanical coupler
under a Tensile Test. A reference bar from the same heat shall be tested to determine its actual
mechanical properties. According to the calculations the mechanical coupler is checked whether it
complies with the related standards or not. Experiment method complies with ISO 15835-2 standard.
3.2 Preparation:
Reinforcing bar specimens are picked up from the jobsite under the supervision of the customer’s
assigned engineer or controller. The couplers shall be positioned in the middle of the test piece. The
test piece for the tensile test shall be sufficiently long to ensure a free length between the grips of the
testing machine to allow determination of percentage total elongation at maximum tensile force(Agt) in
case needed. The minimum sufficient free length, in millimeters, of the test piece for the tensile test is
400+L, where L is the length of mechanical splice (ISO 15835-1). There shall be at least three coupled
samples and one control sample from same diameter. Regnum prepares specimens at 1000mm length
for reliable result. General testing system figure can be seen on Figure 4.
3.3 Testing Equipment:
As stated in ISO 15630-1; the testing machine shall be verified and calibrated in accordance with ISO
7500-1 and shall be at least of class 1. If an extensometer is used, it shall be of class 1 in accordance
with ISO 9513 for the determination of Rp0,2; for the determination of Agt , a class 2 extensometer (see
ISO 9513) can be used. Any extensometer used for the determination of the percentage total elongation
at maximum force (Agt) shall have a gauge length of at least 100 mm. The gauge length shall be indicated
in the test report. Testing equipment can be seen in Figure 4.
3.4 Special Inspection:
Special inspection shall be provided at the test site. The inspector’s duties include verifying grade and
size of reinforcement bar, coupler identification, thread quality of bar, position of coupler and
placement of rebar splices. The specified rib geometry of the test bar shall be controlled as defined in
section 2.2.2.
3.5 Test Procedure:
The test shall be carried out according to ISO 15630-1. A research assistant must attend to test to record
the tensile stress at yielding point and ultimate point for each specimen. For the calculation of stresses,
the nominal cross-sectional area of the reinforcing bar shall be used.
Figure 3 - Testing System View