Bangladesh standard
Specification for
Steel bars and wires
For the reinforcement of concrete
Bangladesh standards and testing institution
116-A, TEJGAON, BANGLADESH
OCTOBER, 1982
80S 1313: 1991
Bangladesh Standard
SPECIFECATION FOR
STEEL BARS AND WIRES FOR
THE REINFORCEMENT OF
CONCRETE
Sectional committee for Structural Steel bars, section and other Products, EDC-12
CHAIRMAN
MR. SHEIKH MD. SHAHiDULLAH
MEMBERS
DR. AHSAK'UL KABiR
DR.M.A.MUKTADIR
MR. ABDUS SAMAD NASER
MR. ABU SAYEDMAKSUD
MR A. K. M. RAFIQUDDIN
ENGINEER AMINUL ISLAM
ENGINEER MR SHAFIQUL ANWAR
MR. A.K.M. SHAMSUL HUD.A
MR.RAN JIT KUMAR ROY
MR. MOPSHED UDDIN
MR.S.A.AINUL KAVI
DR. DELWAR HOSSAIN MR. MR.KHAN HEMAYET UDDIN
MRJALAL UDDIN HUSAIN
MR. SHARIF AHMED
MR. K.M. SHAKUR
STAFF
MR.MD. NURUL ISLAM
Deputy director(engg)
MR.S.MWAHIDUZZAMAN
Examiner(engg)&Secretary to the committee
REPRESENTING
M/S. Shahidullah and Associates, Ltd.
Bangladesh University of Engineering andTechnology
Institute of Architect
Directorate of Supply and inspection
the Engineers Ltd.
Design Development Consultants Ltd.
Project Builders
Bangladesh Chemical industries Corporation
Investment Board
Housing and Building Research institute
Public Works Directorate
Water Development board
Chittagong Steell Mills Ltd.
Bangladesh Steel Re-Rolling Mills Ltd.
Prince Iron and Steel Industries
Bengal Steel Works Ltd.
Rahim Steel Mills Co. Ltd.
Bangladesh standards and testing Institution, Dhaka
Bangladesh standards and testing Institution, Dhaka
Bangladesh standards and testing Institution, Dhaka
BANGLADESH STANDARDS TESTING INSTITUTION
I16-A, TEJGAON INDUSTRIAL AREA, DHAKA-1208
BDS 1313:1991
CONTENTS
0. Foreword page 3
1. Scope page 4
2. Terminology page 4
3. Nominal sizes page 6
4. Cross- sectional area and mass page 6
5. Length page 7
6. Manufacture page 8
7. Chemical compositor page 8
8. Tensile properties page 10
9. Bond classification and deformation requirements of deformed bar page 10
10. Fatigue properties of deformed bar page 12
11. Specified characteristic strength page 12
12. Selection of the sample page 12
13. Preparation of test pieces page 13
14. Tensile test page 13
15. Bending and re-bending requirements page 13
16. Routine inspection and testing page 14
17. Purchaser’s test of chemical composition page 15
18. Purchaser’s lest of weld ability page 15
19. Purchaser’s chaser's verification of specified characteristic strength page 16
20. Purchaser’s further tests page 16
21. Examination after delivery 17 page
22. Marking of bars page 17
23. Information to be supplied by the purchaser page 17
24. Test certificate page 17
APPENDICES
A: Determination of the effective cross-sectional area of deformed bars page 18
B: Bond classification of deformed bars (Bond test) page 19
C: Recommended formula for calculating protected rib area page 21
D: Method of test for fatigue properties of deformed bars page 22
E: Tensile test equivalence ratios page 23
F: Tensile yield strength and elongation of steel page 24
BDS 1313: 1991
Bangladesh Standard
SPECIFICATION FOR
STEEL BARS AND WIRES FOR
THE REINFORCEM ENT OF CONCRETE
0. FOREWORD
0.1 This Bangladesh Standard was adopted by the Bangladesh Standards and Testing
Institution after the draft was finalized by the Sectional Committee for structural steel bar,
section and other products and had been endorsed by the Engineering Divisional
Committee (Civil) on 12 March 1392.
0.2 This standard was first adopted by Civil Engineering Divisional Committee on 18th
December, 1990.meanwhile we have received a number of suggestion and comments on
Various articles of this standard to modify according to the improved manufacturing process
and materials. While reviewing the standard the committee was very particular about the
Requirements of the country and accordingly amendments were incorporated, in related
Clauses. This standard supersedes all related standards so far published.
0.3 in preparation of this standard assistance has been drawn from the 3S 444S: 1988,
ASTM (Part-4): A 615M-1960, 1S-1786: 1985 and assistance so derived is acknowledged
With thanks.
0.4 Deformed bars for concrete reinforcement are being produced in the country for many
Years, the main processes being hot rolling or hot rolling followed by cold twisting. In the past
Decade there has an increasing demand for higher strength deformed bars (400 N/mm²,
Min, yield strength/0.2 percent proof stress being the most common). This high yield strength
was being first achieved by raising carbon and manganese and to a great extent by cold
Twisting. In addition to this there has been considerable demand for larger diameter
Bars with similar strength elongation, weldabilty and bend ability as that of small size bars.
Along with this there is also a need for these e steel bars to be welded and fabricated on the
Site easily. For this, strength and ductility have to be achieved at the lowest possible carbon
Content
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BDS 1313:1991
0.5 This standard is subject to periodical reviews and amendments to cope with the latest
industrial and technological innovations. Any suggestion for improvement will be recorded
and placed before the committee in due course.
0.6 In formulation of this standard due consideration has been given to international co-
ordination among the standards and practices, prevailing in different countries in addition to
Relating it to the practices in the field in this country.
1. SCOPE
1.1 This standard specifies requirements for plain and deformed steel bars and wires for
use as reinforcement in concrete in the following types and grades:
a) Plain bars Grade 250 and 275.
b) Deformed bars Grade 275, 350 and 400.
c) Plain and deformed bars and wires Grade 275, 350, 40O and 500
1.2 This standard also specifies weld ability requirements for ail grades of steel in terms of
the carbon equivalent value.
1.3 Steel bars produced by re-rolling finished products of by rolling material whose
metallurgical properties or, lot-wise chemical composition and mechanical properties is not
known and not fully documented particularly in case of bars re-rolled directly from ship
brewing material are outside the scope of this standard. The lot for the above purpose shall
Be identified on the basis of identity or near-identity of hardness.
2. TERMINOLOGY
For the purpose of this standard the following definitions shall apply
2.1 Bar-A bar is straight piece of steel either plain round or deformed intended for use as
Reinforcement in reinforced concrete construction (RCC). Bars may be hot rolled or cold
Worked.
2.2 Plain bar - A plain bar is a bar without any deformation or surface irregularity over the
Surface and with uniform area of cross section throughout the length.
2.3 Deformed -A deformed bar is a bar whose surface is provided with ribs and lugs
or protrusions (hero in after called deformations) which inhibit longitudinal movement of the
bar relative to the concrete which surrounds the bar in such construction and conform to the
provisions of this specification.
3.4 Hot-rolled bars - A bar rolled in heated conditions and without further mechanical
Treatment after cooling.
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BDS 1313: 1991
2.5 Cold worked bar - A bar which has been cold-worked (cold-twisted, cold-rolled or
cold drawn) after hot rolling.
2.6 Cool/Wire -A continuous as rolled bar in the form of a coil.
2.7 Wire -Wire shall mean cold drawn steel wire in sizes not less than 2 mm dia nor more
than 16mm dia. Deformed steel wire shall mean cold worked deformed steel wire not less
than neither 3 mm dia nor more than 16 mm dia.
2.8 Length - A piece of nominally straight bar cut to a specified length.
2.9 Bundle -Two or more coils or a number of lengths properly bound together.
2.10 Batch - Any quantity of bars of same size and grade whether in coils or bundles
produced by one manufacturer or supplier, organized for examination and test at one time.
2.11 Longitudinal rib - A continuous rib of uniform cross-section parallel to the bar
(before cold-twisting, if any).
2.12 Transverse rib -Any rib on the surface of the bar/wire other than a longitudinal rib.
2.13 Flush butt weld - Resistance but weld in which the components are progressively
advanced towards each other while the electrical current, confirmed to localized points of
contact causes expulsion of molten metal. When welding temperature is reached, upset
force is applied.
2.14 Nominal diameter/ Size - The diameter of a bar/wire having the same mass per
meter length as calculated on the basis that those steel have a mass of 0.00785 kg/mm per
meter run.
2.15 Nominal mass -The mass of the bar/wire of nominal diameter and of density
0.00785 kg/mm² per meter run.
2.16. Yield strength - This is the stresses value at which an appreciable elongation of
Yielding of the material takes place without any corresponding increase in load. In the case of
steels with no such definite yield point, stress value corresponding to 0.5% total strain over
gauge length of the test piece shall be applicable.
2.17 Tensile strength- or ultimate tensile, strength -The maximum load reached
in a tensile test divided by the cross-sectional area calculated on the basis of the nominal dia
of the bar.
2.18 Characteristic strength -That value of the yield, strength below which shall fall
not more than 5% of the test results of the material supplied.
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BUS 1313: 1391
2.19 Elongation - The increase in length of a tensile test piece under stress and
is expressed as a percentage of increase in length over original gauge length of a standard
test piece.
3. NOMINAL SIZES
3.1 Plain and deformed bars - The range of nominal sizes of bars on all grades shall
be from 8 mm to 50 mm. The preferred nominal sizes bars are given below. Nominal bar dia
in mm 8, 10, 12, 16, 20, 22, 25 28, 32 and 40.
3.2 Wires - The preferred nominal sizes of wires are given below :
Nominal wire dia in mm = 4, 5, 6, 7, and 8.
3.3 Other sizes may also be supplied by mutual agreement between the manufacturers
and the purchasers.
4. CROSS SECTIONAL AREA AND MASS.
4.1 The values for the nominal cross-sectional area and mass shall be as given in
table 1.
TABLE 1. CROSS - SECTIONAL AREA AND MASS
Nominal size mm Cross sectional areamm² Mass per meter run Kg
4 12.6 0.099
5 19.6 0.154
6 28,3 0.222
7 38.5 0.302
8 50.3 0.395
10 78.5 0.616
12 113.0 0.888
16 201.0 1.579
20 314.0 2.466
22 380.0 2.98
25 491.0 3.854
28 616.0 4.83
32 804.0 6.313
40 1257.0 9.864
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BDS 1313: 1991
4.2 Effective cross-sectional area - For bars/wires whose nominal diameter is found
by visual inspection reasonably uniform throughout the length of the bar/wire, the effective
Cross-sectional area shall be the gross cross-sectional area determined as follows, using a
Bar/wire net less than 0.5m in length.
Gross cross-sectional area in mm² = w/0.00785 L
where,
W= Mass in kg weighed to a precision of ± 0.5 percent, and L= Length in m
measured to a precision of ± 0.5 percent.
NOTE: Cross-sectional area has been calculated (see appendix A) to the nearest
round off figure as far as practicable.
4.3 Tolerances on mass - The mass of individual bars as given in table 1 shall be
subject to the tolerances given in table 2.
TABLE 2. TOLERANCES ON MASS
Nominal size (mm) Tolerance of mass per meter run(%)
Up to 7 ± 8.0
8 to 12 ± 6.0
Over 12 ± 4.5
4.4 Tolerance on diameter - Permissible tolerance on dia for plain bars and deformed
bars will be same. If the plain bars are to be used for other than use as concrete
reinforcement, the out of round that is the difference between minimum and maximum
diameter at same section shall not exceed 2. 5% for 12 mm and less sizes nor 1.8 for sizes larger than 12 mm.
5.LENGTH
Each bar shall be cut to ± 25 mm of the length specified by the purchaser.
Where a minimum length are specified, the deviations shall be + 50 mm and - 0 mm; and
where maximum lengths arc specified, the deviations shall be - 50 mm + 0 mm.
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BDS 1313: 1991
6. MANUFACTURE
6.1 Steel shall be manufactured by the open - hearth, electric, duplex, basic oxygen
or a combination of these processes.
6.2 Steel shall be supplied semi - killed or killed.
6.3 The bars/wires shall be manufactured from properly identified heats of mould cast,
continuously cast steel or rolled semis.
6.4 The steel bars for concrete reinforcement shall be manufactured by the process of hot-
rolling. It may be followed by a suitable method of cooling and/ or cold-working for improving
tensile properties.
7. CHEMICAL COMPOSITION
7.1 Cast analysis - The chemical composition of the steel based on cast analysis shall
be in accordance with table 3.
TABLE 3. CHEMICAL COMPOSITION OF STEEL GRADES:CAST ANALYSIS
Element Readily weld able grade Grades weld able under specia
(Grade 250.275 and all Arrangement (Grade 350 and 400
cold worked bars/wires) (%) hot-rolled bars /wires only) (%)
Carbon 0.250 Max. 0.400 Max.
Sulphur 0.055 Max. 0.050 Max.
Phosphorous 0.055 Max. 0.050 Max.
Nitrogen 0.012 Max. 0.012 Max.
Silicon 0.500 Max. 0.500 Max.
TABLE 4. MAXIMUM CARBON EQUIVALENT VALUES: CAST ANALYSIS
Grade Maximum carbon equivalent values
Readily weld able grades 0.42
Grades weld able under special arrangement 0.55
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BDS 1313:1991
7.2 The following formula shall be used to calculate the carbon equivalent value where the
Individual values are calculated as percentages:
Carbon equivalent value = C+(Mn/6)+(Cr+Mo+V)/5+(Ni+Cu)/15
Where,
C is the percentage carbon content.
Mn is the percentage manganese content
Cr is the percentage chromium content
V is the percentage vanadium content
Mo is the percentage molybdenum content
Cu is the percentage copper content
Ni is the percentage nickel content
NOTE: Carbon equivalent value shall be determined only when agreed between the
manufacturer/supplier and the purchaser for ascertaining weld ability of the bars.
7.3 Product analysis and permitted deviations.
7.3.1 In case of product analysis; the permissible deviation from the limits specified in table
3 shall be as given in table 5.
TABLE 5. MAXIMUM DEVIATIONS IN CHEMICAL COMPOSITION
ON PRODUCT ANALYSIS
Element Deviation above the specified maximum given
in table 3 and 4
Carbon 0.030 %
Sulphur 0.005 %
Phosphorous 0.005 %
Nitrogen 0.001 %
Carbon equivalent value 0.030 %
7.3.2 In case of deviations from the specified maximum, two additional test samples shall
be taken from the same batch and subjected to the test or tests in which the original sample
Note : Cast analysis for nitrogen and silicon are optional.
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BDS 1313:1991
failed. Should both additional test samples pass the test, the batch from which they were
taken shall be deemed to comply with this standard. Should either of them fails, the batch
shall be deemed not to comply with this standard.
8. TENSILE PROPERTIESThe specified characteristic strength and elongation of both the grades of steel shall be as
given in table 6. The tensile strength of any bar shall be greater than the actual yield strength
measured in the tensile test by at least 15% for grades 250, 275,350, end 400 and atleast
10% for grade 5CO.
TABLE 6.TENSILE PROPERTIES
Grade Nominal size of Specified characteristic Minimum elongation
bar strength (N/mm² ) gauge length (Lo) %
250 All sizes 250 22
275 do 275 20
350 do 350 14
400 do 400 12
500 do 500 8
NOTE: L0 = 5ø where L 0 is the gauge length of the test piece and 0 is the nominal
diameter of the test piece.
9. BOND CLASSIFICATION AND DEFORMATION REQUIREMENTS OF
DEFORMED BAR
9.1 Bond classification - Deformed bars shall be classified either a type 1 (as rolled bars) or type 2 (cold-twisted bars) as follows:
a) In accordance; with their surface, as specified in 9.1.1. or
b) for bars which do not comply with the surface shape bond classification of 9.1.1
In accordance with 9.1.2.
9.1 Bond Classification by Surface Shape
BCIIQ classification by surface shape shall be as follows:
Type 1. As rolled bars - Bars with transverse ribs with a substantial spacing not
Greater than 0.8ø
Type 2. Cold-twisted bars - Bars with transverse ribs with a substantial spacing
not greater than 1.2 ø
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BDS 1313:1991
9.1.2 Bond classification by performance - Deformed bars claimed to be equal in
Bond performance to those satisfying the classification given in 9.1.1 will hold the specified
characteristic strength for at least 2 minutes in a pool out test with a free end slip not greater
than 0.2 mm.
9.1.3 The performance tests described in appendix B shall be conducted by BSTI or any
competent test laboratory recognized by BSTI. The bond classification established by the
Laboratory and given on the test report shall be regarded as final.
9.2 Deformation requirement - Deformation requirements shall fulfill the following:
9.2.1 Spacing of transverse ribs shall be as per limits specified under 9.1.1. (For both type 1 and type
2 bars). The deformations on opposite sides of the bar shall be similar in size and shape.
9.2.1.1 Deformation shall be spaced along the wire at a substantially uniform distance
and shall be symmetrically disposed around the perimeter of the section. The deformations
on all longitudinal lines of the wire shall be similar in size and shape. A minimum of 25
percent of the total surface area shall be deformed by measurable indentations.
9.2.2 Deformed wire shall have two, four, or six lines of deformations.
9.2.1.3 The average longitudinal spacing of deformations shall be not less than 1.4 nor
more thai1 2.2 deformations per centimeter in each line of deformations on the wire.
9.2.1.4 The minimum average height at the center or typical deformations based on the
Nominal wire diameters shown in tables 1 shall be as follows:
Minimum average
Height of deformations,
Percent of nominal wire diameter.
Wire sizes Diameter
5 mm and finer 4
Coarser than 5 mm through 9 mm 4.5
Coarser than 9 mm 5
9.2.2 For both type 1 and type 2 bars, mean area of transverse ribs and lugs (per unit
length) above the core c: the bar projected on a plane normal to the axis of the bar shall be
not less than 0.15ø mm² /mm, where 6 is the nominal bar size (in mm). Recommended
formula for the calculation of the projected rib area given in appendix C.
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BDS 1313: 1991
10. FATIGUE PROPERTIES OF DEFORMED BAR.
Deform 3d bars shall be subjected to type testing as described in appendix D to deter
the fatigue characteristics of a particular geometrical shape. There after the characteristic
shall be confirmed by periodic testing on a three yearly cycle.
For both type and period testing, deformed bars shall endure 5 X 10 to the power 6 cycles of stress.
11. SPECIFIED CHARACTERISTIC STRENGTH
The steel shall be considered to comply with the specified characteristic strengths in table
Provided that, for each size and type of bar.
(a) Not more than two test results of yield stress in any 40 consecutive tests on the
material supplied and less than the specified characteristic strength.
(b) No test results on material supplied are less than 93% of the specified
characteristic strength.
When a new type or size of bar is introduced, item (a) above shall apply to any number
tests until the first 40 have been accumulated.
12. SELECTION OF THE TEST SAMPLES
For the specified tests, samples shall be 600 mm long or 20 times the nominal
size whichever is the greater. Samples shall be selected from each batch at a frequency
of r less than one per X tones or part thereof, where X has the value given in table 7, provids
that, if a batch comprises bars from more than one cast, at least one test sample shall be
t selected to represent each cast. Samples for the bend and rebend tests shall not be
selected from the same bar.TABLE7. FREQUENCY OF TENSILE, BEND AND REBEND TESTING
value of x(quantity of material in tonnes
nominal size of bar for tensile test For bend test For rebend test
Under 10mm 25 50 50
1 0mm to 16mm 35 70 70
20mm to 32mm 45 90 90
Over 32mm 55 110 110
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BDS 1313: 1991
13.1 PREPARATION OF TEST PIECES1 3.1 The tensile, bend and rebend shall normally be carried out on straight bars in the as-
rolled condition without machining or prior heat treatment.
13.2 Only in the case of 40 mm and 50 mm size high yield bars, where a tensile testing
machine of adequate capacity is not available, may such bars be machined to 32 mm
diameter for tensile testing provided that there are equivalence ratios predetermined by
testing similar samples of such bars as-rolled and machined, (See appendix E).
In case of dispute or for purchaser's tests machining shall not be carried out.
14. TENSILE TEST
1 4.1 The tensile yield strength and elongation of the steel shall be determined generally in
accordance with appendix F.
The strain rate when approaching the yield strength shall correspond to a rate of loading not
exceeding 10 N/mm per second.
When the yield strength result is in doubt or dispute, the yield strength shall not have been
deemed to be reached until the total extension is observed to be 0.5% of the test piece
gauge length.
1 4.2 The strength shall be calculated using the cross-sectional area of the bar tested. For
all bars the effective cross-sectional area shall be determined by weighing as in Appendix A.
15. BENDING AMD RE-BENDING REQUIREMENTS
15.1 The bond and re-bend test specimens shall stand being bent around a pin without
cracking on the outside of the bent portion. Tests shall be done at ambient temperature.
15.2 The test shall be made on specimens of sufficient length to ensure free bending and
With apparatus which provides:
15.2.1 Continuous and uniform application of force throughout the duration of the bending
Operation.
15.2.2 Unrestricted movement of the points of contact with the apparatus and bending
around a pin free 10 rotate, or bending about a central pin on a simple span with end
supports free to rotate.
15 .3 Bend test shall be clone by bending the test specimens through 180° around a
former specified in table 8.
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BDS 1313: 1991
TABLE: 8. BEND TEST FORMERS
Grade Nominal sizes Mandrel dia
250/275 All sizes 2d
350/400 Up to and including 25 mm 3d
20 mm to 25 mm 4d
28 mm and above 5d
500 All sizes 5d
Where, d = nominal dia of the bar
15.4 Rebend test shall be done by subjecting the test specimens to the following sequence
of operations.
a) Send the test specimen through 45º around a mandrel of diameter as specified
in table 9.
b) Immerse the test specimen in boiling water (100º c) for not less than 30 minutes.
c) Allow The test specimen to cool down to ambient temperature and then bend it
Backwards through at least 23º around the same mandrel used in (a) above.
TABLES 9. RE-BEND TEST FORMERS
Grade Nominal sizes Manndrel dia
250/275 All sizes 3d
Upto and including 25 mm 5d
350/400 28 mm and above 7d
500 All above 7d
16. ROUTINE INSPECTION AND TESTING
All material shall be subject to routine inspection and testing by the manufacturer or the
supplier in accordance with this standard, and a record of the consecutive test results of
materials complying with the requirements of this standard shall be kept by the manufacturer
or the supplier. The records shall be available for inspection by the purchaser or his
Representative
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BDS 1313: 1991
17. PURCHASER'S TEST OF CHEMICAL COMPOSITION
17.1 Chemical composition - The chemical composition based upon product analysis
as a result of heterogeneity arising during casting and solidification of the steel.
17.2 Killed sleds - For steels an excess is permitted above the maximum in table 3 of
0.03% for carbon and 0. 008% for sulphur and phosphorous.
17.3 Balanced Steels
17.3.1 For balanced steels an excess is permitted above the maximum in table 3 of 0.05%
for carbon and 0.008% for sulphur and phosphorous.
1 7.3,2 the supply of an incorrect grade of balanced steel is clearly indicated by a carbon
content in any bar in excess of 0.10% above the maximum in table 3.
17, 3.3 When the carbon content results of a product analysis lie in the range of 0. 05% to
0.10% above the maximum in table 3, further random samples shall be taken from the
remainder of the batch as in table 10.
TABLE 10. RATE OF FURTHER SAMPLING TO TEST CARBON CONTENT IN BALANCED STEELS
Delivered mass of batch Minimum number of samples per cast
Up to 5 2
Over 5 and up to 20 5
Over 20 2 8
It any further sample shows a carbon content in excess of 0. 05% above the maximum in
Table 3, the supply of an incorrect grade of steel is indicated.
17.3.-l The manufacturer or the supplier shall be given the opportunity of analyzing
the same bars as the purchaser. If any of these further samples are proved
to be outside the permitted variation in 17.3.1, the batch shall be deemed not
to comply with the requirements of this standard.
18. PURCHASER'S TEST OF WELDABILITYThe purchasers, in conjunction with the manufacturer
and /or the supplier,
shall carry out weld ability tests as agreed between the parties concerned.
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BDS 1313: 199119. PURCHASER'S VERIFICATION OF SPECIFIED CHARACTERISTIC
STRENGTH
19.1 in the circumstances where a purchaser requires to verify that the specified
characteristic strength is attained by a batch of steel, he shall first agree with the supplier at
what establishment the steel is to be tested.
If the issue of testing or identification of testing laboratories is not embodied in the
agreement between purchaser and supplier, the purchaser shall have the right of testing in
BSTI laboratory or a laboratory recognized by BSTI.
19.2 Ten test specimens shall be selected from each different bars size in the batch.
If any one test result \t- less than 93% of the specified characteristic strength both the
specimen and the test method shall be carefully examined. If there is a local fault in the
specimen or reason to believe that an error has occurred in the test, the bar from which the
specimen was taken shall be disregarded and the test result shall be ignored.
If the valid test results have a yield strength equal to or greater than 93% of the specified
characteristic strength, the batch shall be deemed to comply with this standard in respect of
the specified 3d characteristic strength requirements.
if one or more valid results is less than 93% of the specified characteristic strength the batch
shall be darned not to comply with the requirements of this standard.
19.3 Where the purchaser is satisfied that routine testing has been carried out he may use
an alternative abbreviated purchaser's test as follows.
Three test specimens shall 06 selected for each bar size from different bars in the batch. If
any one test result I is less than 93% or the specified characteristic strength the requirements
of 19.2 snail apply, if the three valid test results have a yield strength equal to or greater than
the specified characteristic strength, the batch shall be deemed to comply with the
requirements of this standard in respect of the specified characteristic strength requirements.
20. PURCHASER'S FURTHER TESTSShould any sample. (average of 3 lest pieces) fail to meet the tensile strength,
elongation,
bend or re-bend test requirements, two additional test samples shall be taken from the same
batch and subjected to the lest or tests in which the original sample failed. Should both
additional test samples pass the test or tests the batch from which they were taken shall be
deemed to comply with the requirements of this standard. Should either of them fail , the
batch snail be deemed not to comply with the requirements of this standard. This procedure
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BDS 1313: 1991
Shall not apply in the case of specified characteristic strength as this is dealt with in
Clause 19.
21.EXAMINATION AFTER DELIVERY
Should any material after delivery be found not to be in accordance with this standard, such
material shall be deemed not to comply with the requirements of this standard not
withstanding any previous acceptance. Defects that are the result of improper treatment after
delivery shall not be considered to be grounds for rejection.
22.MARKING OF BARS
22.1 All. bars shall bear the print of monogram trade mark of the rolling/re-rolling mill at
intervals not greater than 1 .5 m. Bars other than plain bars shall also bear the print of grade
of the oar as intervals not greater than 1.5 m.
22.2 Each bundle containing the bars shall be legibly and indelibly marked with the
following
a.number of this Bangladesh standard.
b.Dale of manufacture.
c. Rerolled from (Billet/scrap)
22.3 Each bundle may also be marked with the BSTI certification mark.
NOTE:the use or the BSTI Certification Mark is governed by the provisions of the
Bangladesh Standards and Testing Institution Ordinance 1985, and Regulations
made hereunder. The details of conditions for obtaining license for using standard
mark may ho obtained from the Institution.
23. INFORMATION TO BE SUPPLIED BY THE PURCHASER
The purchaser shall give the following basic requirements on the order :
a) the number of this Bangladesh standard;
b) the- nominal size of the bar
c) the steel grade;
d) Dona classifications;
e) any additional requirements.
24) TEST CERTIFICATE
24.1 upon request from a user, the manufacturer or the supplier shall issue a certificate of
testing stating ;
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BDS 1313:1991
(a) that the material supplied complies with the requirements and has been tested at
the frequency specified in this standard;
(b) it appropriate, the carbon equivalent value;
(c) the address at which the record of test results is available for inspection.
24.2 In the case of material delivered to a supplier, the manufacturer shall issue a certificate of testing stating:
(a) the cast analysis of the bars supplied;
(b) if appropriate, the carbon equivalent value;
(c) The results of the tensile, bend and rebend tests on samples taken from the
material; the tensile test results shall include the cross-sectional area.
APPENDIX — A
(Reference Clause 4.2)
DETERMINATION OF THE EFFECTIVE CROSS-SECTIONAL
AREA OF DEFORMED BARS
A-1 UNIFORM CROSS-SECTIONAL AREA
For bars where the configuration is such that, by visual inspection, the cross-sectional area is substantially uniform along the length of the bar, the effective cross-sectional area A, shall be the gross cross-sectional area, in millimeter squared, determined by weighing and measuring to a precision of ± 0. 5% a length of not less than 0.5 m and calculated as
A= M/0.0 0785 L
where,M is the mass of the bar (in kg) ;
L is the length of the bar (in m).
A - 2 VARIABLE CROSS-SECTIONAL AREA
A - 2.1 or a bar where the cross-sectional area varies along its length, a sample not less
than 0.5 m shall be weighed (M) and measured to a precision of ±.0.5% in the as
manufactured condition, and after the transverse ribs have been removed it shall be
reweighed (M´ )
A - 2.2 Where the difference between the two masses (M - M´) is less than 3% of M´
the effective cross-sectional area shall be obtained as in A-1
page 18
BDS 1313 : 1991A – 2.3 Where the difference between the two masses (M - M') ii equal to or greater than
3% c (M´ ), the effective cross-sectional area A, in millimeters squared, shall be calculated
as follows :
A=1.03M/0.0078L
Where
M´ is the mass of the bar with transverse ribs removed (in kg);
L is the length of the bar (in m).
For routine test purposes a nominal ratio of effective to gross cross-sectional area of bars
covered by A-2. 3 shall be stated and used by the manufacturer.
APPENDIX —B
(Reference Clause 9)
BOND CLASSIFICATION OF DEFORMED BARS (BOND TEST)
B-1 PRINCIPLEPrincipia of the test is to show that deformed bars, claimed to be equal to those satisfying
the classification given in 9.11 will hold for a given time the specified characteristic strength
(see table 6) in a pull-out test with a free end slip not greater than 0.2 mm.
B-2 SELECTION OF TEST SPECIMENSFor a range of sizes of bar which are geometrically similar in shape, tests shall be carried
out on two sizes, preferably 20 mm and the largest available size. The surface shape of the
bars to be tested shall comply with the manufacturer's published specification, and shall be
as near to the minimum amount of deformation as is possible. Six specimens of each size
shall be tested.
B-3 TEST PRISMSFor each of the specimens prepare a concrete test prism having a square cross section of
150 mm side for bars up to and including 20 mm size, and 25 mm side for bars over 20 mm
size. The length of prism, L, in millimetres, shall be calculated as follows :
L = fyø/21 deformed type 1 bar and
L = fyø/21 deformed type 2 bars
page 19
1313: 1991
Where,
Fү is the specified characteristic strength of the steel (in N/mm²)
ø the nominal bar size (in mm).
Prepare the prisms using a mortar mix that gives a concrete having a cubes strength of
between 40 N/mm2 and 45 N/mrn2 at the time of the pull-out test. Support the test bar so
that it is rigidly embedded in and passes completely through the prisms. of concrete along its
longitudinal axis. Reinforce the prism along the embedded length with a helix of 6 mm
diameter plain mild steel having a pitch of 25 mm, the outer diameter of the helix being 5 mm
loss than the side of the square section A.
B-4 APPARATUSMount the test specimen m the testing device in such a manner that the bar is pulled axially
from the prism. Arrange the test piece such that the end of the bar at which the pull is
applied is that which projected from the top end of the prism as cast. Place plaster bending
or rubber or plywood packing between the top end of the prism and the surface of the testing
device hearing on it.Mount a auditable dial gauge in such a manner that the gauge records the relative slip
between the unloaded end of thy bar and the bottom end of the prism as cast.
B-5 PROCEDUREDuring a period of approximately 2 rain, steadily increases the axial force in the bar
protruding from the top end of the prism until the (ensile stress in the bar attains the specified
characteristic strength f for !he grade of steel from which the bars are made. Maintain this
stress for a further 2 min then record the free end slip of the bar.
B-6 FREE END SLIP If the average free end slip of the six bars tested exceeds o. mm they shall not quality for
that classification.
B-7 TEST REPORT
The test report shall contain the following informations: (a) mill of manufacture.
(b) bar size.
(c) Rib geometry.
page 20
BDS 1313: 1991
(d)Concrete strength
(e) The bend classification determined.
NOTE: Fanner information may be included by agreement.
APPENDIX — C
(Reference Clause 9.2.2)
RECOMMENDED FORMULAE FOR CALCULATING PROJECTED RIB AREA
The projected rib area should be calculated for ribbed bars using one of the following equations:
(a) For as-rolled deformed bars the projected rib area, in millimeters squared per millimetre, from the equation.
R=n (Iα sinβ) ⁄ c
(b) For cold twister bars for projected rib area R, in millimeters squared per millimeter, from the equation
Rn=n (Iα sinβ) ⁄ c +NA nΦ ⁄ p
Where,
n is number of rows or transverse ribs . When more than one pattern of transverse
ribe exits,e.g alternate ribs having different angles or different rib patterns in each
row, the first term shall be the sum of the calculated values for each set of ribs.
i is the length of the transverse rib measured at the rib to core interface determined
as the average of three measurements on each row or set of transverse ribs (in mm).
a is the height of the transverse rib measured perpendicular to the core of the bar
determine: as the average of three measurements or each row of set of transverse
ribs fin mm/ (using Simpsons's rule for approximation under a curve, with rib height
measurements at tne mind and quarter points, the rib height for each rib profile may
be established, as a proportion of its mid point height. For transverse ribs of
parabolic profile the rib height shall be taken as 2/3 of the mid point height.
B is the angle of the centre line of the transverse rib to the bar axis (in degrees).
C is the centre- to centre spacing of transverse ribs determined by dividing the distance,
measured parallel to the axis of the bar, between the mid points of two ribs, of the
page 21
BDS 1313:1991
Order of ten ribs apart, by the number of rib spaces in between. In the case of twisted
bars this will necessitate counting rib spaces in a helical fashion.
N is the number of longitudinal
A is the height of the longitudinal rib determined as the average of three
measurements on each rib (in mm).
P is the pitch of twist measured parallel to the bar axis determined as the average of
three measurements (in mm).
Φ is the nominal bar size
APPENDIX — D
(Reference Clause 10)
METHOD OF TEST FOR FATIGUE PROPERTIES OF DEFORMED BARS
D - 1 FATIGUE TESTING
The fatigue properties for each defined bar shape and process route shall be established by a
competent test laboratory initially by testing three sizes selected from the top, intermediate
and bottom of preferred size range. The full product size range shall be tested on three cycles.
Testing shall be carried out in batches on oars in the commercially straight condition. Bars
shall be deemed defective or non-defective depending upon their ability to endure 5 X 106
cycles of stress at the stress range given to the relevant bar size in table 11.
TABLE 11. TEST STRESSES RANGES FOR NOMINAL SIZES
Bar size (mm) Stresses range (N/mm²)
Up to and including 16 200
Over 16 up to and including 20 185
Over 20 up to and including 25 170
Over 25 up to and including 32 160
Over 32 up to and including 40 150
page 22
BDS 1313: 1991D-2 SAMPLING
For sampling purposes cars shall be formed into batches of 60 bars of a single type and
size, manufactured at the same time. Test specimens shall not be taken from bars exhibiting
isolated defects which are not characteristic the product. Each test specimen shall be cut
from a bar selected at random and shall have a minimum length of 30 d and a minimum free
length of :0 c where d is the nominal diameter of the test specimen. The test unit shall
comprise five test specimens.
D-3 TEST PROCEDURE
Test specimens shall be tested in air under axial tensile loading using tapered grips
and a suitable gripping medium. The stress ratio shall be 0.2 and the frequency shall not exceed
120 Hz. The size wave from shall be used. Testing shall be carried out under load control
and stresses shall be calculated on the nominal area.
Thu batch shall be deemed to comply with this standard provided that the number of cycles
of stress specified in clause 11 has been not achieved. Where this has been achieved, the
test shall be consider invalid if the failure initiated from a defect unique to the test specimen
an area adjacent to the testing machine grips.D-3 RE TESTS
D - 4.1 the batch shall be deemed to comply with this standard if all five test specimens endure 5 X 10 to the power 6
cycles of stress.D - 4.2 Where two or more test specimens of the five initially selected fail to endure 3 X 10 to the power 6 cycles,
the batch represented shall be deemed not to comply with this standard.D - 4.3 If one valid test specimen, a further five specimens be selected from the batch
represented, if one or more of these specimens fails, the batch shall be deemed not to
comply with this regard.
APPENDIX — E
(Reference Clause 13.2)
TENSILE TEST EQUIVALENCE RATIOS
E- 1 Where a testing machine of adequate capacity is not readily available, high yield
bars of 40 mm and 60 mm size may be machined to 32 mm diameter for the tensile test. In
these case for each type of bar and pattern of deformations equivalence ratios are to be
used to Convert the test values measured on the machined test piece to equivalent values
for the as-rolled bar.
page 23
BDS 1313: 1991
E -2 For each type bar and pattern of deformations the equivalence ratios are to be
pre-determined, once for all, by comparative testing of 25 adjacent pairs of test pieces cut
from at least five bar.
E - 3 The tensile tests en the as-rolled test pieces of each pair are to be carried out using
an averaging extensometer record the total, extension on the gauge length of 0. 5%.
The tensile tests on the machined test pieces are to be carried out using the same testing
machine and extensometer.
E - 4 The following three ratios are to be determined as the averages of the ratios in. the
25 test and are to be included in any test record or certificate where they have been used
To convert test result on machined test piece.
rү=yield stress of as-rolled test piece/Yield stress of machined test piece =yа/ym
rμ=Tensile strength of as-rolled test piece/tensile strength of machined test piece=Tа/Tm
re=Elongation of as-rolled test piece/Elongation of machined test piece=Eа/Em
APPENDIX — F
(Preference Clause 14)
TENSILE YIELD STRENGTH AND ELONGATION OF STEEL
F -1 the yield strength stress shall be determined by one of the following methods:
1) The yield point shall be determined by drop of the beam or halt in the gauge of
the testing machine
2) Where the steel does not have a well-defined yield point, the yield stress
shall be determined by one of the methods indicated in 2.1 and 2.2.
F-2 Extension under load using dividers with a 200 mm gauge length. The extension under'
load shall be 1.o mm and shall be determined by scribing on the specimen 200 mm gauge
length, pivoting from prick punch mark. The yield load shall be recorded when the total
gauge length under load becomes 201 mm as measured by the dividers. . .
F-3 Extension under load using an autographic diagram method or an extensometer. However,
the extension under load shall be 0.5% of gauge length. .
page 24
INTERNATIONAL SYSTEM OF UNITS (SI UNITS)
Base units
quantity Name of units symbol
Length meter m
Mass kilogram kg
Time second S
Electric current ampere A
Thermodynamic temperature Kelvin K
Amount of substance rnole mol
Luminous intensity candela cd
Supplementary Units
Quantity Name of units Symbol
Plane angle Radian rad
Solid angle Steradian sr
Derived Units with Special Name
Quantity Name of unite symbol Expression in terms of other units
Frequency hetz HZ 1HZ=1sÑ1
Force newton N 1N=1kg m/s²
Pressure and stress pascal Pa 1pa=1N/m²
Work,energy,Quantity of heat joule j 1J = 1N m
Power Watt W 1W =1j/s
Quantity of electricity coulomb C 1C =1As
Electric potential,electromotive
force volt V 1V = 1W/A
Electric capacitance farad F 1F=1A s/V
Electric restance home Ω 1 Ω=1V/A
Electric conductance siemens S 1S =1A/v
Magnetic flux Weber Wb 1Wb =1Vs
Magnetic flux density tesla T 1T =1Wb/m²
Luminous flux lumen Im 1Im = 1cdsr
Celsius temperature Degree celsius ºC K
Some Other Derived Units
Area Square meter m² —
Volume Cubic meter m³ —
Capacity (Liquid) litre I —
BANGLADESH STANDARDS AND TESTING INSTIT UTION
116-A,Tejgon Industrial Area,Dhaka-1208,Bangladesh
page 25
Specification for
Steel bars and wires
For the reinforcement of concrete
Bangladesh standards and testing institution
116-A, TEJGAON, BANGLADESH
OCTOBER, 1982
80S 1313: 1991
Bangladesh Standard
SPECIFECATION FOR
STEEL BARS AND WIRES FOR
THE REINFORCEMENT OF
CONCRETE
Sectional committee for Structural Steel bars, section and other Products, EDC-12
CHAIRMAN
MR. SHEIKH MD. SHAHiDULLAH
MEMBERS
DR. AHSAK'UL KABiR
DR.M.A.MUKTADIR
MR. ABDUS SAMAD NASER
MR. ABU SAYEDMAKSUD
MR A. K. M. RAFIQUDDIN
ENGINEER AMINUL ISLAM
ENGINEER MR SHAFIQUL ANWAR
MR. A.K.M. SHAMSUL HUD.A
MR.RAN JIT KUMAR ROY
MR. MOPSHED UDDIN
MR.S.A.AINUL KAVI
DR. DELWAR HOSSAIN MR. MR.KHAN HEMAYET UDDIN
MRJALAL UDDIN HUSAIN
MR. SHARIF AHMED
MR. K.M. SHAKUR
STAFF
MR.MD. NURUL ISLAM
Deputy director(engg)
MR.S.MWAHIDUZZAMAN
Examiner(engg)&Secretary to the committee
REPRESENTING
M/S. Shahidullah and Associates, Ltd.
Bangladesh University of Engineering andTechnology
Institute of Architect
Directorate of Supply and inspection
the Engineers Ltd.
Design Development Consultants Ltd.
Project Builders
Bangladesh Chemical industries Corporation
Investment Board
Housing and Building Research institute
Public Works Directorate
Water Development board
Chittagong Steell Mills Ltd.
Bangladesh Steel Re-Rolling Mills Ltd.
Prince Iron and Steel Industries
Bengal Steel Works Ltd.
Rahim Steel Mills Co. Ltd.
Bangladesh standards and testing Institution, Dhaka
Bangladesh standards and testing Institution, Dhaka
Bangladesh standards and testing Institution, Dhaka
BANGLADESH STANDARDS TESTING INSTITUTION
I16-A, TEJGAON INDUSTRIAL AREA, DHAKA-1208
BDS 1313:1991
CONTENTS
0. Foreword page 3
1. Scope page 4
2. Terminology page 4
3. Nominal sizes page 6
4. Cross- sectional area and mass page 6
5. Length page 7
6. Manufacture page 8
7. Chemical compositor page 8
8. Tensile properties page 10
9. Bond classification and deformation requirements of deformed bar page 10
10. Fatigue properties of deformed bar page 12
11. Specified characteristic strength page 12
12. Selection of the sample page 12
13. Preparation of test pieces page 13
14. Tensile test page 13
15. Bending and re-bending requirements page 13
16. Routine inspection and testing page 14
17. Purchaser’s test of chemical composition page 15
18. Purchaser’s lest of weld ability page 15
19. Purchaser’s chaser's verification of specified characteristic strength page 16
20. Purchaser’s further tests page 16
21. Examination after delivery 17 page
22. Marking of bars page 17
23. Information to be supplied by the purchaser page 17
24. Test certificate page 17
APPENDICES
A: Determination of the effective cross-sectional area of deformed bars page 18
B: Bond classification of deformed bars (Bond test) page 19
C: Recommended formula for calculating protected rib area page 21
D: Method of test for fatigue properties of deformed bars page 22
E: Tensile test equivalence ratios page 23
F: Tensile yield strength and elongation of steel page 24
BDS 1313: 1991
Bangladesh Standard
SPECIFICATION FOR
STEEL BARS AND WIRES FOR
THE REINFORCEM ENT OF CONCRETE
0. FOREWORD
0.1 This Bangladesh Standard was adopted by the Bangladesh Standards and Testing
Institution after the draft was finalized by the Sectional Committee for structural steel bar,
section and other products and had been endorsed by the Engineering Divisional
Committee (Civil) on 12 March 1392.
0.2 This standard was first adopted by Civil Engineering Divisional Committee on 18th
December, 1990.meanwhile we have received a number of suggestion and comments on
Various articles of this standard to modify according to the improved manufacturing process
and materials. While reviewing the standard the committee was very particular about the
Requirements of the country and accordingly amendments were incorporated, in related
Clauses. This standard supersedes all related standards so far published.
0.3 in preparation of this standard assistance has been drawn from the 3S 444S: 1988,
ASTM (Part-4): A 615M-1960, 1S-1786: 1985 and assistance so derived is acknowledged
With thanks.
0.4 Deformed bars for concrete reinforcement are being produced in the country for many
Years, the main processes being hot rolling or hot rolling followed by cold twisting. In the past
Decade there has an increasing demand for higher strength deformed bars (400 N/mm²,
Min, yield strength/0.2 percent proof stress being the most common). This high yield strength
was being first achieved by raising carbon and manganese and to a great extent by cold
Twisting. In addition to this there has been considerable demand for larger diameter
Bars with similar strength elongation, weldabilty and bend ability as that of small size bars.
Along with this there is also a need for these e steel bars to be welded and fabricated on the
Site easily. For this, strength and ductility have to be achieved at the lowest possible carbon
Content
page 3
BDS 1313:1991
0.5 This standard is subject to periodical reviews and amendments to cope with the latest
industrial and technological innovations. Any suggestion for improvement will be recorded
and placed before the committee in due course.
0.6 In formulation of this standard due consideration has been given to international co-
ordination among the standards and practices, prevailing in different countries in addition to
Relating it to the practices in the field in this country.
1. SCOPE
1.1 This standard specifies requirements for plain and deformed steel bars and wires for
use as reinforcement in concrete in the following types and grades:
a) Plain bars Grade 250 and 275.
b) Deformed bars Grade 275, 350 and 400.
c) Plain and deformed bars and wires Grade 275, 350, 40O and 500
1.2 This standard also specifies weld ability requirements for ail grades of steel in terms of
the carbon equivalent value.
1.3 Steel bars produced by re-rolling finished products of by rolling material whose
metallurgical properties or, lot-wise chemical composition and mechanical properties is not
known and not fully documented particularly in case of bars re-rolled directly from ship
brewing material are outside the scope of this standard. The lot for the above purpose shall
Be identified on the basis of identity or near-identity of hardness.
2. TERMINOLOGY
For the purpose of this standard the following definitions shall apply
2.1 Bar-A bar is straight piece of steel either plain round or deformed intended for use as
Reinforcement in reinforced concrete construction (RCC). Bars may be hot rolled or cold
Worked.
2.2 Plain bar - A plain bar is a bar without any deformation or surface irregularity over the
Surface and with uniform area of cross section throughout the length.
2.3 Deformed -A deformed bar is a bar whose surface is provided with ribs and lugs
or protrusions (hero in after called deformations) which inhibit longitudinal movement of the
bar relative to the concrete which surrounds the bar in such construction and conform to the
provisions of this specification.
3.4 Hot-rolled bars - A bar rolled in heated conditions and without further mechanical
Treatment after cooling.
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BDS 1313: 1991
2.5 Cold worked bar - A bar which has been cold-worked (cold-twisted, cold-rolled or
cold drawn) after hot rolling.
2.6 Cool/Wire -A continuous as rolled bar in the form of a coil.
2.7 Wire -Wire shall mean cold drawn steel wire in sizes not less than 2 mm dia nor more
than 16mm dia. Deformed steel wire shall mean cold worked deformed steel wire not less
than neither 3 mm dia nor more than 16 mm dia.
2.8 Length - A piece of nominally straight bar cut to a specified length.
2.9 Bundle -Two or more coils or a number of lengths properly bound together.
2.10 Batch - Any quantity of bars of same size and grade whether in coils or bundles
produced by one manufacturer or supplier, organized for examination and test at one time.
2.11 Longitudinal rib - A continuous rib of uniform cross-section parallel to the bar
(before cold-twisting, if any).
2.12 Transverse rib -Any rib on the surface of the bar/wire other than a longitudinal rib.
2.13 Flush butt weld - Resistance but weld in which the components are progressively
advanced towards each other while the electrical current, confirmed to localized points of
contact causes expulsion of molten metal. When welding temperature is reached, upset
force is applied.
2.14 Nominal diameter/ Size - The diameter of a bar/wire having the same mass per
meter length as calculated on the basis that those steel have a mass of 0.00785 kg/mm per
meter run.
2.15 Nominal mass -The mass of the bar/wire of nominal diameter and of density
0.00785 kg/mm² per meter run.
2.16. Yield strength - This is the stresses value at which an appreciable elongation of
Yielding of the material takes place without any corresponding increase in load. In the case of
steels with no such definite yield point, stress value corresponding to 0.5% total strain over
gauge length of the test piece shall be applicable.
2.17 Tensile strength- or ultimate tensile, strength -The maximum load reached
in a tensile test divided by the cross-sectional area calculated on the basis of the nominal dia
of the bar.
2.18 Characteristic strength -That value of the yield, strength below which shall fall
not more than 5% of the test results of the material supplied.
page 5
BUS 1313: 1391
2.19 Elongation - The increase in length of a tensile test piece under stress and
is expressed as a percentage of increase in length over original gauge length of a standard
test piece.
3. NOMINAL SIZES
3.1 Plain and deformed bars - The range of nominal sizes of bars on all grades shall
be from 8 mm to 50 mm. The preferred nominal sizes bars are given below. Nominal bar dia
in mm 8, 10, 12, 16, 20, 22, 25 28, 32 and 40.
3.2 Wires - The preferred nominal sizes of wires are given below :
Nominal wire dia in mm = 4, 5, 6, 7, and 8.
3.3 Other sizes may also be supplied by mutual agreement between the manufacturers
and the purchasers.
4. CROSS SECTIONAL AREA AND MASS.
4.1 The values for the nominal cross-sectional area and mass shall be as given in
table 1.
TABLE 1. CROSS - SECTIONAL AREA AND MASS
Nominal size mm Cross sectional areamm² Mass per meter run Kg
4 12.6 0.099
5 19.6 0.154
6 28,3 0.222
7 38.5 0.302
8 50.3 0.395
10 78.5 0.616
12 113.0 0.888
16 201.0 1.579
20 314.0 2.466
22 380.0 2.98
25 491.0 3.854
28 616.0 4.83
32 804.0 6.313
40 1257.0 9.864
page 6
BDS 1313: 1991
4.2 Effective cross-sectional area - For bars/wires whose nominal diameter is found
by visual inspection reasonably uniform throughout the length of the bar/wire, the effective
Cross-sectional area shall be the gross cross-sectional area determined as follows, using a
Bar/wire net less than 0.5m in length.
Gross cross-sectional area in mm² = w/0.00785 L
where,
W= Mass in kg weighed to a precision of ± 0.5 percent, and L= Length in m
measured to a precision of ± 0.5 percent.
NOTE: Cross-sectional area has been calculated (see appendix A) to the nearest
round off figure as far as practicable.
4.3 Tolerances on mass - The mass of individual bars as given in table 1 shall be
subject to the tolerances given in table 2.
TABLE 2. TOLERANCES ON MASS
Nominal size (mm) Tolerance of mass per meter run(%)
Up to 7 ± 8.0
8 to 12 ± 6.0
Over 12 ± 4.5
4.4 Tolerance on diameter - Permissible tolerance on dia for plain bars and deformed
bars will be same. If the plain bars are to be used for other than use as concrete
reinforcement, the out of round that is the difference between minimum and maximum
diameter at same section shall not exceed 2. 5% for 12 mm and less sizes nor 1.8 for sizes larger than 12 mm.
5.LENGTH
Each bar shall be cut to ± 25 mm of the length specified by the purchaser.
Where a minimum length are specified, the deviations shall be + 50 mm and - 0 mm; and
where maximum lengths arc specified, the deviations shall be - 50 mm + 0 mm.
page 7
BDS 1313: 1991
6. MANUFACTURE
6.1 Steel shall be manufactured by the open - hearth, electric, duplex, basic oxygen
or a combination of these processes.
6.2 Steel shall be supplied semi - killed or killed.
6.3 The bars/wires shall be manufactured from properly identified heats of mould cast,
continuously cast steel or rolled semis.
6.4 The steel bars for concrete reinforcement shall be manufactured by the process of hot-
rolling. It may be followed by a suitable method of cooling and/ or cold-working for improving
tensile properties.
7. CHEMICAL COMPOSITION
7.1 Cast analysis - The chemical composition of the steel based on cast analysis shall
be in accordance with table 3.
TABLE 3. CHEMICAL COMPOSITION OF STEEL GRADES:CAST ANALYSIS
Element Readily weld able grade Grades weld able under specia
(Grade 250.275 and all Arrangement (Grade 350 and 400
cold worked bars/wires) (%) hot-rolled bars /wires only) (%)
Carbon 0.250 Max. 0.400 Max.
Sulphur 0.055 Max. 0.050 Max.
Phosphorous 0.055 Max. 0.050 Max.
Nitrogen 0.012 Max. 0.012 Max.
Silicon 0.500 Max. 0.500 Max.
TABLE 4. MAXIMUM CARBON EQUIVALENT VALUES: CAST ANALYSIS
Grade Maximum carbon equivalent values
Readily weld able grades 0.42
Grades weld able under special arrangement 0.55
page 8
BDS 1313:1991
7.2 The following formula shall be used to calculate the carbon equivalent value where the
Individual values are calculated as percentages:
Carbon equivalent value = C+(Mn/6)+(Cr+Mo+V)/5+(Ni+Cu)/15
Where,
C is the percentage carbon content.
Mn is the percentage manganese content
Cr is the percentage chromium content
V is the percentage vanadium content
Mo is the percentage molybdenum content
Cu is the percentage copper content
Ni is the percentage nickel content
NOTE: Carbon equivalent value shall be determined only when agreed between the
manufacturer/supplier and the purchaser for ascertaining weld ability of the bars.
7.3 Product analysis and permitted deviations.
7.3.1 In case of product analysis; the permissible deviation from the limits specified in table
3 shall be as given in table 5.
TABLE 5. MAXIMUM DEVIATIONS IN CHEMICAL COMPOSITION
ON PRODUCT ANALYSIS
Element Deviation above the specified maximum given
in table 3 and 4
Carbon 0.030 %
Sulphur 0.005 %
Phosphorous 0.005 %
Nitrogen 0.001 %
Carbon equivalent value 0.030 %
7.3.2 In case of deviations from the specified maximum, two additional test samples shall
be taken from the same batch and subjected to the test or tests in which the original sample
Note : Cast analysis for nitrogen and silicon are optional.
page 9
BDS 1313:1991
failed. Should both additional test samples pass the test, the batch from which they were
taken shall be deemed to comply with this standard. Should either of them fails, the batch
shall be deemed not to comply with this standard.
8. TENSILE PROPERTIESThe specified characteristic strength and elongation of both the grades of steel shall be as
given in table 6. The tensile strength of any bar shall be greater than the actual yield strength
measured in the tensile test by at least 15% for grades 250, 275,350, end 400 and atleast
10% for grade 5CO.
TABLE 6.TENSILE PROPERTIES
Grade Nominal size of Specified characteristic Minimum elongation
bar strength (N/mm² ) gauge length (Lo) %
250 All sizes 250 22
275 do 275 20
350 do 350 14
400 do 400 12
500 do 500 8
NOTE: L0 = 5ø where L 0 is the gauge length of the test piece and 0 is the nominal
diameter of the test piece.
9. BOND CLASSIFICATION AND DEFORMATION REQUIREMENTS OF
DEFORMED BAR
9.1 Bond classification - Deformed bars shall be classified either a type 1 (as rolled bars) or type 2 (cold-twisted bars) as follows:
a) In accordance; with their surface, as specified in 9.1.1. or
b) for bars which do not comply with the surface shape bond classification of 9.1.1
In accordance with 9.1.2.
9.1 Bond Classification by Surface Shape
BCIIQ classification by surface shape shall be as follows:
Type 1. As rolled bars - Bars with transverse ribs with a substantial spacing not
Greater than 0.8ø
Type 2. Cold-twisted bars - Bars with transverse ribs with a substantial spacing
not greater than 1.2 ø
page 10
BDS 1313:1991
9.1.2 Bond classification by performance - Deformed bars claimed to be equal in
Bond performance to those satisfying the classification given in 9.1.1 will hold the specified
characteristic strength for at least 2 minutes in a pool out test with a free end slip not greater
than 0.2 mm.
9.1.3 The performance tests described in appendix B shall be conducted by BSTI or any
competent test laboratory recognized by BSTI. The bond classification established by the
Laboratory and given on the test report shall be regarded as final.
9.2 Deformation requirement - Deformation requirements shall fulfill the following:
9.2.1 Spacing of transverse ribs shall be as per limits specified under 9.1.1. (For both type 1 and type
2 bars). The deformations on opposite sides of the bar shall be similar in size and shape.
9.2.1.1 Deformation shall be spaced along the wire at a substantially uniform distance
and shall be symmetrically disposed around the perimeter of the section. The deformations
on all longitudinal lines of the wire shall be similar in size and shape. A minimum of 25
percent of the total surface area shall be deformed by measurable indentations.
9.2.2 Deformed wire shall have two, four, or six lines of deformations.
9.2.1.3 The average longitudinal spacing of deformations shall be not less than 1.4 nor
more thai1 2.2 deformations per centimeter in each line of deformations on the wire.
9.2.1.4 The minimum average height at the center or typical deformations based on the
Nominal wire diameters shown in tables 1 shall be as follows:
Minimum average
Height of deformations,
Percent of nominal wire diameter.
Wire sizes Diameter
5 mm and finer 4
Coarser than 5 mm through 9 mm 4.5
Coarser than 9 mm 5
9.2.2 For both type 1 and type 2 bars, mean area of transverse ribs and lugs (per unit
length) above the core c: the bar projected on a plane normal to the axis of the bar shall be
not less than 0.15ø mm² /mm, where 6 is the nominal bar size (in mm). Recommended
formula for the calculation of the projected rib area given in appendix C.
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BDS 1313: 1991
10. FATIGUE PROPERTIES OF DEFORMED BAR.
Deform 3d bars shall be subjected to type testing as described in appendix D to deter
the fatigue characteristics of a particular geometrical shape. There after the characteristic
shall be confirmed by periodic testing on a three yearly cycle.
For both type and period testing, deformed bars shall endure 5 X 10 to the power 6 cycles of stress.
11. SPECIFIED CHARACTERISTIC STRENGTH
The steel shall be considered to comply with the specified characteristic strengths in table
Provided that, for each size and type of bar.
(a) Not more than two test results of yield stress in any 40 consecutive tests on the
material supplied and less than the specified characteristic strength.
(b) No test results on material supplied are less than 93% of the specified
characteristic strength.
When a new type or size of bar is introduced, item (a) above shall apply to any number
tests until the first 40 have been accumulated.
12. SELECTION OF THE TEST SAMPLES
For the specified tests, samples shall be 600 mm long or 20 times the nominal
size whichever is the greater. Samples shall be selected from each batch at a frequency
of r less than one per X tones or part thereof, where X has the value given in table 7, provids
that, if a batch comprises bars from more than one cast, at least one test sample shall be
t selected to represent each cast. Samples for the bend and rebend tests shall not be
selected from the same bar.TABLE7. FREQUENCY OF TENSILE, BEND AND REBEND TESTING
value of x(quantity of material in tonnes
nominal size of bar for tensile test For bend test For rebend test
Under 10mm 25 50 50
1 0mm to 16mm 35 70 70
20mm to 32mm 45 90 90
Over 32mm 55 110 110
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BDS 1313: 1991
13.1 PREPARATION OF TEST PIECES1 3.1 The tensile, bend and rebend shall normally be carried out on straight bars in the as-
rolled condition without machining or prior heat treatment.
13.2 Only in the case of 40 mm and 50 mm size high yield bars, where a tensile testing
machine of adequate capacity is not available, may such bars be machined to 32 mm
diameter for tensile testing provided that there are equivalence ratios predetermined by
testing similar samples of such bars as-rolled and machined, (See appendix E).
In case of dispute or for purchaser's tests machining shall not be carried out.
14. TENSILE TEST
1 4.1 The tensile yield strength and elongation of the steel shall be determined generally in
accordance with appendix F.
The strain rate when approaching the yield strength shall correspond to a rate of loading not
exceeding 10 N/mm per second.
When the yield strength result is in doubt or dispute, the yield strength shall not have been
deemed to be reached until the total extension is observed to be 0.5% of the test piece
gauge length.
1 4.2 The strength shall be calculated using the cross-sectional area of the bar tested. For
all bars the effective cross-sectional area shall be determined by weighing as in Appendix A.
15. BENDING AMD RE-BENDING REQUIREMENTS
15.1 The bond and re-bend test specimens shall stand being bent around a pin without
cracking on the outside of the bent portion. Tests shall be done at ambient temperature.
15.2 The test shall be made on specimens of sufficient length to ensure free bending and
With apparatus which provides:
15.2.1 Continuous and uniform application of force throughout the duration of the bending
Operation.
15.2.2 Unrestricted movement of the points of contact with the apparatus and bending
around a pin free 10 rotate, or bending about a central pin on a simple span with end
supports free to rotate.
15 .3 Bend test shall be clone by bending the test specimens through 180° around a
former specified in table 8.
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BDS 1313: 1991
TABLE: 8. BEND TEST FORMERS
Grade Nominal sizes Mandrel dia
250/275 All sizes 2d
350/400 Up to and including 25 mm 3d
20 mm to 25 mm 4d
28 mm and above 5d
500 All sizes 5d
Where, d = nominal dia of the bar
15.4 Rebend test shall be done by subjecting the test specimens to the following sequence
of operations.
a) Send the test specimen through 45º around a mandrel of diameter as specified
in table 9.
b) Immerse the test specimen in boiling water (100º c) for not less than 30 minutes.
c) Allow The test specimen to cool down to ambient temperature and then bend it
Backwards through at least 23º around the same mandrel used in (a) above.
TABLES 9. RE-BEND TEST FORMERS
Grade Nominal sizes Manndrel dia
250/275 All sizes 3d
Upto and including 25 mm 5d
350/400 28 mm and above 7d
500 All above 7d
16. ROUTINE INSPECTION AND TESTING
All material shall be subject to routine inspection and testing by the manufacturer or the
supplier in accordance with this standard, and a record of the consecutive test results of
materials complying with the requirements of this standard shall be kept by the manufacturer
or the supplier. The records shall be available for inspection by the purchaser or his
Representative
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BDS 1313: 1991
17. PURCHASER'S TEST OF CHEMICAL COMPOSITION
17.1 Chemical composition - The chemical composition based upon product analysis
as a result of heterogeneity arising during casting and solidification of the steel.
17.2 Killed sleds - For steels an excess is permitted above the maximum in table 3 of
0.03% for carbon and 0. 008% for sulphur and phosphorous.
17.3 Balanced Steels
17.3.1 For balanced steels an excess is permitted above the maximum in table 3 of 0.05%
for carbon and 0.008% for sulphur and phosphorous.
1 7.3,2 the supply of an incorrect grade of balanced steel is clearly indicated by a carbon
content in any bar in excess of 0.10% above the maximum in table 3.
17, 3.3 When the carbon content results of a product analysis lie in the range of 0. 05% to
0.10% above the maximum in table 3, further random samples shall be taken from the
remainder of the batch as in table 10.
TABLE 10. RATE OF FURTHER SAMPLING TO TEST CARBON CONTENT IN BALANCED STEELS
Delivered mass of batch Minimum number of samples per cast
Up to 5 2
Over 5 and up to 20 5
Over 20 2 8
It any further sample shows a carbon content in excess of 0. 05% above the maximum in
Table 3, the supply of an incorrect grade of steel is indicated.
17.3.-l The manufacturer or the supplier shall be given the opportunity of analyzing
the same bars as the purchaser. If any of these further samples are proved
to be outside the permitted variation in 17.3.1, the batch shall be deemed not
to comply with the requirements of this standard.
18. PURCHASER'S TEST OF WELDABILITYThe purchasers, in conjunction with the manufacturer
and /or the supplier,
shall carry out weld ability tests as agreed between the parties concerned.
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BDS 1313: 199119. PURCHASER'S VERIFICATION OF SPECIFIED CHARACTERISTIC
STRENGTH
19.1 in the circumstances where a purchaser requires to verify that the specified
characteristic strength is attained by a batch of steel, he shall first agree with the supplier at
what establishment the steel is to be tested.
If the issue of testing or identification of testing laboratories is not embodied in the
agreement between purchaser and supplier, the purchaser shall have the right of testing in
BSTI laboratory or a laboratory recognized by BSTI.
19.2 Ten test specimens shall be selected from each different bars size in the batch.
If any one test result \t- less than 93% of the specified characteristic strength both the
specimen and the test method shall be carefully examined. If there is a local fault in the
specimen or reason to believe that an error has occurred in the test, the bar from which the
specimen was taken shall be disregarded and the test result shall be ignored.
If the valid test results have a yield strength equal to or greater than 93% of the specified
characteristic strength, the batch shall be deemed to comply with this standard in respect of
the specified 3d characteristic strength requirements.
if one or more valid results is less than 93% of the specified characteristic strength the batch
shall be darned not to comply with the requirements of this standard.
19.3 Where the purchaser is satisfied that routine testing has been carried out he may use
an alternative abbreviated purchaser's test as follows.
Three test specimens shall 06 selected for each bar size from different bars in the batch. If
any one test result I is less than 93% or the specified characteristic strength the requirements
of 19.2 snail apply, if the three valid test results have a yield strength equal to or greater than
the specified characteristic strength, the batch shall be deemed to comply with the
requirements of this standard in respect of the specified characteristic strength requirements.
20. PURCHASER'S FURTHER TESTSShould any sample. (average of 3 lest pieces) fail to meet the tensile strength,
elongation,
bend or re-bend test requirements, two additional test samples shall be taken from the same
batch and subjected to the lest or tests in which the original sample failed. Should both
additional test samples pass the test or tests the batch from which they were taken shall be
deemed to comply with the requirements of this standard. Should either of them fail , the
batch snail be deemed not to comply with the requirements of this standard. This procedure
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BDS 1313: 1991
Shall not apply in the case of specified characteristic strength as this is dealt with in
Clause 19.
21.EXAMINATION AFTER DELIVERY
Should any material after delivery be found not to be in accordance with this standard, such
material shall be deemed not to comply with the requirements of this standard not
withstanding any previous acceptance. Defects that are the result of improper treatment after
delivery shall not be considered to be grounds for rejection.
22.MARKING OF BARS
22.1 All. bars shall bear the print of monogram trade mark of the rolling/re-rolling mill at
intervals not greater than 1 .5 m. Bars other than plain bars shall also bear the print of grade
of the oar as intervals not greater than 1.5 m.
22.2 Each bundle containing the bars shall be legibly and indelibly marked with the
following
a.number of this Bangladesh standard.
b.Dale of manufacture.
c. Rerolled from (Billet/scrap)
22.3 Each bundle may also be marked with the BSTI certification mark.
NOTE:the use or the BSTI Certification Mark is governed by the provisions of the
Bangladesh Standards and Testing Institution Ordinance 1985, and Regulations
made hereunder. The details of conditions for obtaining license for using standard
mark may ho obtained from the Institution.
23. INFORMATION TO BE SUPPLIED BY THE PURCHASER
The purchaser shall give the following basic requirements on the order :
a) the number of this Bangladesh standard;
b) the- nominal size of the bar
c) the steel grade;
d) Dona classifications;
e) any additional requirements.
24) TEST CERTIFICATE
24.1 upon request from a user, the manufacturer or the supplier shall issue a certificate of
testing stating ;
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BDS 1313:1991
(a) that the material supplied complies with the requirements and has been tested at
the frequency specified in this standard;
(b) it appropriate, the carbon equivalent value;
(c) the address at which the record of test results is available for inspection.
24.2 In the case of material delivered to a supplier, the manufacturer shall issue a certificate of testing stating:
(a) the cast analysis of the bars supplied;
(b) if appropriate, the carbon equivalent value;
(c) The results of the tensile, bend and rebend tests on samples taken from the
material; the tensile test results shall include the cross-sectional area.
APPENDIX — A
(Reference Clause 4.2)
DETERMINATION OF THE EFFECTIVE CROSS-SECTIONAL
AREA OF DEFORMED BARS
A-1 UNIFORM CROSS-SECTIONAL AREA
For bars where the configuration is such that, by visual inspection, the cross-sectional area is substantially uniform along the length of the bar, the effective cross-sectional area A, shall be the gross cross-sectional area, in millimeter squared, determined by weighing and measuring to a precision of ± 0. 5% a length of not less than 0.5 m and calculated as
A= M/0.0 0785 L
where,M is the mass of the bar (in kg) ;
L is the length of the bar (in m).
A - 2 VARIABLE CROSS-SECTIONAL AREA
A - 2.1 or a bar where the cross-sectional area varies along its length, a sample not less
than 0.5 m shall be weighed (M) and measured to a precision of ±.0.5% in the as
manufactured condition, and after the transverse ribs have been removed it shall be
reweighed (M´ )
A - 2.2 Where the difference between the two masses (M - M´) is less than 3% of M´
the effective cross-sectional area shall be obtained as in A-1
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BDS 1313 : 1991A – 2.3 Where the difference between the two masses (M - M') ii equal to or greater than
3% c (M´ ), the effective cross-sectional area A, in millimeters squared, shall be calculated
as follows :
A=1.03M/0.0078L
Where
M´ is the mass of the bar with transverse ribs removed (in kg);
L is the length of the bar (in m).
For routine test purposes a nominal ratio of effective to gross cross-sectional area of bars
covered by A-2. 3 shall be stated and used by the manufacturer.
APPENDIX —B
(Reference Clause 9)
BOND CLASSIFICATION OF DEFORMED BARS (BOND TEST)
B-1 PRINCIPLEPrincipia of the test is to show that deformed bars, claimed to be equal to those satisfying
the classification given in 9.11 will hold for a given time the specified characteristic strength
(see table 6) in a pull-out test with a free end slip not greater than 0.2 mm.
B-2 SELECTION OF TEST SPECIMENSFor a range of sizes of bar which are geometrically similar in shape, tests shall be carried
out on two sizes, preferably 20 mm and the largest available size. The surface shape of the
bars to be tested shall comply with the manufacturer's published specification, and shall be
as near to the minimum amount of deformation as is possible. Six specimens of each size
shall be tested.
B-3 TEST PRISMSFor each of the specimens prepare a concrete test prism having a square cross section of
150 mm side for bars up to and including 20 mm size, and 25 mm side for bars over 20 mm
size. The length of prism, L, in millimetres, shall be calculated as follows :
L = fyø/21 deformed type 1 bar and
L = fyø/21 deformed type 2 bars
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1313: 1991
Where,
Fү is the specified characteristic strength of the steel (in N/mm²)
ø the nominal bar size (in mm).
Prepare the prisms using a mortar mix that gives a concrete having a cubes strength of
between 40 N/mm2 and 45 N/mrn2 at the time of the pull-out test. Support the test bar so
that it is rigidly embedded in and passes completely through the prisms. of concrete along its
longitudinal axis. Reinforce the prism along the embedded length with a helix of 6 mm
diameter plain mild steel having a pitch of 25 mm, the outer diameter of the helix being 5 mm
loss than the side of the square section A.
B-4 APPARATUSMount the test specimen m the testing device in such a manner that the bar is pulled axially
from the prism. Arrange the test piece such that the end of the bar at which the pull is
applied is that which projected from the top end of the prism as cast. Place plaster bending
or rubber or plywood packing between the top end of the prism and the surface of the testing
device hearing on it.Mount a auditable dial gauge in such a manner that the gauge records the relative slip
between the unloaded end of thy bar and the bottom end of the prism as cast.
B-5 PROCEDUREDuring a period of approximately 2 rain, steadily increases the axial force in the bar
protruding from the top end of the prism until the (ensile stress in the bar attains the specified
characteristic strength f for !he grade of steel from which the bars are made. Maintain this
stress for a further 2 min then record the free end slip of the bar.
B-6 FREE END SLIP If the average free end slip of the six bars tested exceeds o. mm they shall not quality for
that classification.
B-7 TEST REPORT
The test report shall contain the following informations: (a) mill of manufacture.
(b) bar size.
(c) Rib geometry.
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BDS 1313: 1991
(d)Concrete strength
(e) The bend classification determined.
NOTE: Fanner information may be included by agreement.
APPENDIX — C
(Reference Clause 9.2.2)
RECOMMENDED FORMULAE FOR CALCULATING PROJECTED RIB AREA
The projected rib area should be calculated for ribbed bars using one of the following equations:
(a) For as-rolled deformed bars the projected rib area, in millimeters squared per millimetre, from the equation.
R=n (Iα sinβ) ⁄ c
(b) For cold twister bars for projected rib area R, in millimeters squared per millimeter, from the equation
Rn=n (Iα sinβ) ⁄ c +NA nΦ ⁄ p
Where,
n is number of rows or transverse ribs . When more than one pattern of transverse
ribe exits,e.g alternate ribs having different angles or different rib patterns in each
row, the first term shall be the sum of the calculated values for each set of ribs.
i is the length of the transverse rib measured at the rib to core interface determined
as the average of three measurements on each row or set of transverse ribs (in mm).
a is the height of the transverse rib measured perpendicular to the core of the bar
determine: as the average of three measurements or each row of set of transverse
ribs fin mm/ (using Simpsons's rule for approximation under a curve, with rib height
measurements at tne mind and quarter points, the rib height for each rib profile may
be established, as a proportion of its mid point height. For transverse ribs of
parabolic profile the rib height shall be taken as 2/3 of the mid point height.
B is the angle of the centre line of the transverse rib to the bar axis (in degrees).
C is the centre- to centre spacing of transverse ribs determined by dividing the distance,
measured parallel to the axis of the bar, between the mid points of two ribs, of the
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BDS 1313:1991
Order of ten ribs apart, by the number of rib spaces in between. In the case of twisted
bars this will necessitate counting rib spaces in a helical fashion.
N is the number of longitudinal
A is the height of the longitudinal rib determined as the average of three
measurements on each rib (in mm).
P is the pitch of twist measured parallel to the bar axis determined as the average of
three measurements (in mm).
Φ is the nominal bar size
APPENDIX — D
(Reference Clause 10)
METHOD OF TEST FOR FATIGUE PROPERTIES OF DEFORMED BARS
D - 1 FATIGUE TESTING
The fatigue properties for each defined bar shape and process route shall be established by a
competent test laboratory initially by testing three sizes selected from the top, intermediate
and bottom of preferred size range. The full product size range shall be tested on three cycles.
Testing shall be carried out in batches on oars in the commercially straight condition. Bars
shall be deemed defective or non-defective depending upon their ability to endure 5 X 106
cycles of stress at the stress range given to the relevant bar size in table 11.
TABLE 11. TEST STRESSES RANGES FOR NOMINAL SIZES
Bar size (mm) Stresses range (N/mm²)
Up to and including 16 200
Over 16 up to and including 20 185
Over 20 up to and including 25 170
Over 25 up to and including 32 160
Over 32 up to and including 40 150
page 22
BDS 1313: 1991D-2 SAMPLING
For sampling purposes cars shall be formed into batches of 60 bars of a single type and
size, manufactured at the same time. Test specimens shall not be taken from bars exhibiting
isolated defects which are not characteristic the product. Each test specimen shall be cut
from a bar selected at random and shall have a minimum length of 30 d and a minimum free
length of :0 c where d is the nominal diameter of the test specimen. The test unit shall
comprise five test specimens.
D-3 TEST PROCEDURE
Test specimens shall be tested in air under axial tensile loading using tapered grips
and a suitable gripping medium. The stress ratio shall be 0.2 and the frequency shall not exceed
120 Hz. The size wave from shall be used. Testing shall be carried out under load control
and stresses shall be calculated on the nominal area.
Thu batch shall be deemed to comply with this standard provided that the number of cycles
of stress specified in clause 11 has been not achieved. Where this has been achieved, the
test shall be consider invalid if the failure initiated from a defect unique to the test specimen
an area adjacent to the testing machine grips.D-3 RE TESTS
D - 4.1 the batch shall be deemed to comply with this standard if all five test specimens endure 5 X 10 to the power 6
cycles of stress.D - 4.2 Where two or more test specimens of the five initially selected fail to endure 3 X 10 to the power 6 cycles,
the batch represented shall be deemed not to comply with this standard.D - 4.3 If one valid test specimen, a further five specimens be selected from the batch
represented, if one or more of these specimens fails, the batch shall be deemed not to
comply with this regard.
APPENDIX — E
(Reference Clause 13.2)
TENSILE TEST EQUIVALENCE RATIOS
E- 1 Where a testing machine of adequate capacity is not readily available, high yield
bars of 40 mm and 60 mm size may be machined to 32 mm diameter for the tensile test. In
these case for each type of bar and pattern of deformations equivalence ratios are to be
used to Convert the test values measured on the machined test piece to equivalent values
for the as-rolled bar.
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BDS 1313: 1991
E -2 For each type bar and pattern of deformations the equivalence ratios are to be
pre-determined, once for all, by comparative testing of 25 adjacent pairs of test pieces cut
from at least five bar.
E - 3 The tensile tests en the as-rolled test pieces of each pair are to be carried out using
an averaging extensometer record the total, extension on the gauge length of 0. 5%.
The tensile tests on the machined test pieces are to be carried out using the same testing
machine and extensometer.
E - 4 The following three ratios are to be determined as the averages of the ratios in. the
25 test and are to be included in any test record or certificate where they have been used
To convert test result on machined test piece.
rү=yield stress of as-rolled test piece/Yield stress of machined test piece =yа/ym
rμ=Tensile strength of as-rolled test piece/tensile strength of machined test piece=Tа/Tm
re=Elongation of as-rolled test piece/Elongation of machined test piece=Eа/Em
APPENDIX — F
(Preference Clause 14)
TENSILE YIELD STRENGTH AND ELONGATION OF STEEL
F -1 the yield strength stress shall be determined by one of the following methods:
1) The yield point shall be determined by drop of the beam or halt in the gauge of
the testing machine
2) Where the steel does not have a well-defined yield point, the yield stress
shall be determined by one of the methods indicated in 2.1 and 2.2.
F-2 Extension under load using dividers with a 200 mm gauge length. The extension under'
load shall be 1.o mm and shall be determined by scribing on the specimen 200 mm gauge
length, pivoting from prick punch mark. The yield load shall be recorded when the total
gauge length under load becomes 201 mm as measured by the dividers. . .
F-3 Extension under load using an autographic diagram method or an extensometer. However,
the extension under load shall be 0.5% of gauge length. .
page 24
INTERNATIONAL SYSTEM OF UNITS (SI UNITS)
Base units
quantity Name of units symbol
Length meter m
Mass kilogram kg
Time second S
Electric current ampere A
Thermodynamic temperature Kelvin K
Amount of substance rnole mol
Luminous intensity candela cd
Supplementary Units
Quantity Name of units Symbol
Plane angle Radian rad
Solid angle Steradian sr
Derived Units with Special Name
Quantity Name of unite symbol Expression in terms of other units
Frequency hetz HZ 1HZ=1sÑ1
Force newton N 1N=1kg m/s²
Pressure and stress pascal Pa 1pa=1N/m²
Work,energy,Quantity of heat joule j 1J = 1N m
Power Watt W 1W =1j/s
Quantity of electricity coulomb C 1C =1As
Electric potential,electromotive
force volt V 1V = 1W/A
Electric capacitance farad F 1F=1A s/V
Electric restance home Ω 1 Ω=1V/A
Electric conductance siemens S 1S =1A/v
Magnetic flux Weber Wb 1Wb =1Vs
Magnetic flux density tesla T 1T =1Wb/m²
Luminous flux lumen Im 1Im = 1cdsr
Celsius temperature Degree celsius ºC K
Some Other Derived Units
Area Square meter m² —
Volume Cubic meter m³ —
Capacity (Liquid) litre I —
BANGLADESH STANDARDS AND TESTING INSTIT UTION
116-A,Tejgon Industrial Area,Dhaka-1208,Bangladesh
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