DEPARTMENT OF CIVIL ENGINEERING
Materials of Construction and Testing
EXPERIMENT 16: TENSILE STRENGTH OF REINFORCING STEEL BARS
16.1. Program Outcomes (POs) Addressed by the Experiment
b) Ability to design and conduct experiments, as well as to analyze and interpret data.
d) Ability to function on multidisciplinary teams.
16.2. Experiment’s Intended Learning Outcomes (EILOs)
At the end of this experiment the student shall be able to:
a) Classify the grade of reinforcing steel bars.
b) Apply appropriate ASTM/AASHTO standards for tension testing of reinforcing steel
bars.
c) Compute the tensile strength, yield strength and elongation of reinforcing steel bars.
16.3. Objectives of the Experiment
The objective of this experiment is to determine the yield point, tensile strength and
elongation of the reinforcing steel bar.
16.4. Principle of the Experiment
Tensile strength can be calculated by dividing the maximum load the specimen sustains
during test with the nominal cross – sectional area of the specimen.
Yield strength by dividing the load sustained by the specimen at the sudden halt of the
load indicating pointer by the nominal cross – sectional area of the specimen.
Elongation evaluates the ductility of the steel. It can be expressed as the increase in
length of the gage length as a percentage of the original gage length.
16.5. Materials / Equipment
Universal Testing Machine
Testing Grips
Micrometer Caliper / Scale
Balance
Measuring Tape
Labelling Devices
16.6. Procedure
1. Prepare approximately one meter of reinforcing steel bar and measure its length.
2. Determine the average diameter of the reinforcing steel bar and determine its weight.
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3. Mark in the center of the test specimen a 200 mm (8 inches) gage length. Set suitable
grips in the testing to hold the specimens and apply the load until rupture at a uniform
rate.
4. Note the load at the sudden halt of the load indicating pointer and record the
corresponding stress as yield point as well as the maximum load attained by the
material until rupture.
5. After fracture, fit the ends of the fractured specimen together carefully and measure
the distance between the gage marks for the determination of its percent elongation.
16.7. Activity Report
Course: Experiment No.:
Group No.: Section:
Group Members: Date Performed:
Date Submitted:
Instructor:
16.8. Data and Results
DATA:
Initial length (mm)
Length after fracture (mm)
Trial Diameter (mm)
1
2
3
Average
RESULTS:
Yield Strength (MPa)
Ultimate Strength (MPa)
Strain
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16.9. Calculation
16.10. Observation
16.11. Conclusion/s
In conclusion, it is important to measure the initial length correctly and must be lower compared to final length. If
wrong measurement is done, as for example higher intial length compared to final length, negative strain value will
be determined which is not acceptable since given steel is subjected to tensile stress. On the other hand, by using the
universal testing machine, the yield strength and ultimate strength is easily determined resulting 441.560 MPa and
569.520 MPa, respectively.
16.12. References
ASTM A615/A615M. (2016). Standard Specification for Deformed and Plain Carbon Steel
Bars for Concrete Reinforcement. West Conshohocken, PA: ASTM International.
ASTM E8/E8M. (2009). Standard Test Methods for Tension Testing of Metallic Materials. West
Conshohocken, PA: ASTM International.
Bureau of Reserach and Standards. (2014). Laboratory Testing Procedures Manual:
Miscellaneous Construction Materials (Vol. V). Quezon City: Department of Public Works and
Highways.
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