STEEL BARSTEEL BAR(Reinforcing Steel)(Reinforcing Steel)

- Embedded in concrete for the purpose of resisting a particular stress.

TYPES OF STEELTYPES OF STEEL

a) Deformed Steel Bar -the surface of which is provided with lugs (deformation)

b) Plain Steel Bar -a rolled steel bar

without surface deformation

DEFORMED BARS IDENTIFYING DEFORMED BARS IDENTIFYING MARKS:MARKS:

Manufacturer’s Identifying Marks Bar Size – dot ( min. of 3 mm dia.) Mark Size, mm (Number of dots) (Nominal Diameter) 1 8 2 10 3 12 4 16 5 20 6 25 7 28 8 32 9 36 Bar Grade – dash (parallel to the rib) or grade

number itself 1 dash – grade 40 2 dashes – grade 60 W - weldable grade

Markings for Grade 40, size= 25mmØ, Weldable Deformed BarMarkings for Grade 40, size= 25mmØ, Weldable Deformed Bar

M

I

••

•• ••

W

25

W

Manufacturer’sMarking

Bar Grade

Bar Size

Weldable

Color CodeColor Code(Painted on the surface of the end of the bar)(Painted on the surface of the end of the bar)

Bar Grade ColorGrade 30 White

Grade 40 Yellow

Grade 60 Green

Weldable Grade Red (additional color code)

TABLE 1: Deformed Bar Designation Numbers,TABLE 1: Deformed Bar Designation Numbers, Nominal weights(Masses) and Deformation Requirements Nominal weights(Masses) and Deformation Requirements

Bar Designation

No.

Nominal Mass Kg./m

Deformation Requirements, mm

Average Spacing (Max.)

Average Height (Min.)

Maximum Gap (Max.)

10 0.560 6.7 0.38 3.6

13 0.994 8.9 0.51 4.9

16 1.552 11.1 0.71 6.1

19 2.235 13.3 0.97 7.3

22 3.042 15.5 1.12 8.5

25 3.973 17.8 1.27 9.7

29 5.060 20.1 1.42 10.9

32 6.404 22.6 1.63 12.4

36 7.907 25.1 1.80 13.7

43 11.38 30.1 2.16 16.5

57 20.24 40.1 2.59 21.9

LABORATORY TEST OF STEEL:LABORATORY TEST OF STEEL: Physical Test : a) unit weight determination b) tension test c) bending test

Chemical Test : testing of alloying elements of steel (Phosphorous, Carbon & Sulfur)

Preliminary testPreliminary test for Deformed Bar for Deformed Bar

Measurement of length and determination of the weight of specimen.

Measurement of deformations: a) Average spacing – determined by dividing the length of

sample with at least eleven deformations by the number of spaces on any one side of the test specimen.

b) Average height – determine from measurements made on not less than two typical deformations.

c) Average gap – the distance between the extreme ends of the lugs.

PROCEDURE OF TENSION PROCEDURE OF TENSION TEST:TEST:

Mark in the center of the test specimen a 200mm (8”) gage length. Set the test sample in the testing machine and apply the load until rapture at a uniform rate.

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 steel until rapture.

After fracture, fit the ends of the fractured specimen together carefully and measure the distance between the gage marks for elongation(%) determination.

Apparatus:• Micrometer caliper/scale• Weighing balance• steel measuring tape• Universal Testing Machine 1 – Physical test for every 10,000 kgs. (1 meter length sample)

UNIVERSAL TESTING MACHINE (UTMUNIVERSAL TESTING MACHINE (UTM))

UNIVERSAL TESTING MACHINE (UTM)UNIVERSAL TESTING MACHINE (UTM)

Determination of Yield point & Tensile Strength

Determination of tensile, yield & elongationDetermination of tensile, yield & elongation

Tensile strength – the ultimate strength of steel bar. (Obtained by dividing the maximum load by the original specimen cross sectional area of steel)

Yield strength – the initial strength of steel bar. (Obtained by dividing the load uphold by the cross sectional area of the specimen).

Elongation of SteelElongation of Steel

200 mm (8”) gage length markBefore tension test

Elongated steel sample After tension test

Elongation = evaluates the ductility of steel

Worksheet for Steel Bars

Project: ___________________________________________Contractor: ____________________________________________

DATAClass: ( ) Plain (X) Deformed _25 mm Elongation, mm a) Final 320 b) Gage length 200Nominal mass kg/m (table) 3.973 c) Difference 120Length of specimen, mm __ 1004_ Deformation:Mass of Specimen, kg. __ 3.970 a) average spacing 170/10= 17.0 b) ave. height 1.65

Pin diameter, mm: 1.005-S 1.005-S degree of bend __90 ___ 1.65 .940 .940 1.65 Bend __ S____

c) ave. gap _.158 - .158= 4.01

Computation:Computation:

Area (Cross-sectional area): a)Plain, mm² = ∏ D² ; b) Deformed, mm² = mass of steel 4 Density x

length of steelA = _ 3.970 kg.________________ = 503.718 mm² 1004 mm x 7.85 tonnes x 1000kg x __(1m)³__ m³ ton (1000mm)³ Unit mass of Steel , kg/m = __3.970kgs.__ x 1000 mm = 3.954 1004 mm 1m Variation in mass, % = 3.954 – 3.973 x 100 = - 0.478 % under 3.973 Elongation, % = Final – Gage length (difference) = _110_ x 100 =

55 % Gage length 200 Yield Point, Mpa = 532 (initial loading / cross-sectional area) Tensile Strength, Mpa = 683 (maximum load/ cross-sectional area)

Properties AASHTO M31/ASTM 615STD. Specifications for Deformed &

Plain Steel Bars Bar Grade 40 60 75

Tensile Strength, MPa (min.)

420 620 690

Yield Strength, MPa (min.) 280 420 520

Elongation, % (min.) AASHTO M31/ASTM 615Bar Diameter, mm Grade 40 Grade 60 Grade75

10 11 9 -

12, 16, 20 12 9 7

25 - 8 7

28, 32 - 7 6

36 - 7 6

Properties Philippine National Standard (PNS): 49

STD. Specifications for Deformed & Plain Steel Bars

Bar Grade 30 40 60

Tensile Strength, MPa (min.)

390 480 620

Yield Strength, MPa (min.) 230 275 415Elongation, % (minimum)GRADE Bar Diameter, mm NW W

30 ˂ 25 mmØ 18 20

≥ 25 mmØ 16 18

40 ˂ 25 mmØ 10 16

≥ 25 mmØ 8 14

60 ˂ 25 mmØ 8 14

≥ 25 mmØ 7 12

Bending of SteelBending of Steel

*The test specimen shall withstand being bent around a pin with continuous and uniform application of force throughout the duration of the bending operation without cracking on the outside bent portion.

*It evaluates the brittleness of steel and also the ductility of steel.

1 Physical test for every 10,000 kgs. (1meter length sample)

Pin Diameter Requirement Pin Diameter Requirement for Bending Testfor Bending Test

Nominal Diameter of Steel, Pin Diameter,

10 – 20 mm 6 d 25 – 28 mm 8 d 32 & greater 10 d

Procedure: (Bending of Procedure: (Bending of Steel)Steel)

Place the specimen for bending test on the rollers of a cold bend apparatus and bend thru the specified angle by a pin attached to the head of the machine.

Apply a continuous and uniform load throughout the bending operation.

Examine carefully the bent portion for any sign of cracking on the outside bend.

BENDINGBENDING TESTTEST OF STEELOF STEEL

Bending test of Steel Bending test of Steel (Con’t.)(Con’t.)

Steel sample after Bending TestSteel sample after Bending Test

Properties AASHTO M31/ ASTM 615

PNS: 49

Bending Requirement No cracking on outside bent

No cracking on outside bent

Variation in mass, % 6.0 max. under nominal mass

+ 6 max. nominal mass

Phosphorous Content, %

0.06 maximum 0.06 maximum

Acceptance and Rejection:

* Insufficient height, insufficient circumferential coverage, or excessive spacing of deformations shall not constitute cause for rejection .

* No rejection shall be made on the basis of measurements if fewer than ten adjacent deformations of each side of the bar are measured.

* In no case shall overweight (excess mass) of any deformed bar be the cause for rejection.

DIFFERENT TYPES OF DIFFERENT TYPES OF STRUCTURAL STEELSTRUCTURAL STEEL

●BARS ●PLATES ●SHAPES

1 Physical test for every 50,000 kgs./1- mill test certificate1 Physical test per shipment/ 1- inspection report

Standard Test Specimen Standard Test Specimen for Rectangular/Plate Sample for Rectangular/Plate Sample

Standard Test SpecimenStandard Test Specimen for Circular/Pipe Sample for Circular/Pipe Sample

The test procedure for tension test of miscellaneous steel are the same as in testing of Reinforcing Steel Bar, except for the test specimen.

DPWH Standard Specifications DPWH Standard Specifications for Miscellaneous Structural Steelfor Miscellaneous Structural Steel

METAL STRUCTURE (Item – 403)/STRUCTURAL STEEL (Item – 712)(For Plates, Shapes & Bars) AASHTO M 183

Tensile Strength, MPa 400 min. – 550 max.

Yield Point, MPa 250 min.

Elongation, % 20 min.

STEEL SHEET PILE /PILING(Item – 509/400)

AASHTO M 202

Tensile Strength, MPa 485 min.

Yield Point, MPa 270 min.

Elongation, % 17

GUARDRAIL (Item – 603) AASHTO M 180Tensile Strength, MPa 483 (70,000 psi) min.

Yield Point, MPa 345 (50,000 psi) min.

Elongation, % 12 min.

GOOD LUCK