Concrete_and_Reinforced_Concrete for graduates

concrete apllication

1. Concrete Design

2. Concrete It is an artificial stone derived from a mixture of properly proportioned amount of hydraulic cement, fine aggregates, coarse aggregates and water, with or without admixtures. A mixture of Portland cement or any other hydraulic cement, fine aggregates, course aggregates and water, with or without admixtures.

3. Admixture Is a material other than water, aggregate or hydraulic cement used as an ingredient of concrete and added to concrete before and during ots mixing to modify its properties.

4. Admixture Accelerator – an admixture which hasten the hardening rate and/or initial setting time of concrete. Retarder – an admixture which slows the setting rate of concrete.

5. Concrete Design Mix Typical distribution of raw materials by volume for a normal strength concrete.

6. Note: Cement accounts for most of the concrete raw material cost. Concrete Design Mix

7. Reinforced Concrete Is a composite material in which concrete’s relatively low tensile strength and ductility are countered by the inclusion of reinforcement having higher tensile strength and ductility.

8. Choice of slump If slump is not specified, a value appropriate for the work can be selected from the given table: Table A1.5.3.1 Recommended Slumps for Various Types of Construction (SI) Types of construction Slump, mm Maximum Minimum Reinforced foundation walls and footings 75 25 Plain footings, caissons & substructure walls 75 25 Beams and reinforced walls 100 25 Building columns 100 25 Pavements and Slabs 75 25 Mass concrete 75 25

9. Slump Test Slump is a measurement of concrete's workability, or fluidity. It's an indirect measurement of concrete consistency or stiffness.

10. Types of Slumps The slumped concrete takes various shapes, and according to the profile of slumped concrete, the slump is termed as;

11. Apparatus Slump Mold Dimension of Slump Cone: Diameter of the base – 203 mm Diameter of the top – 102 mm Altitude – 305 mm

12. Apparatus Tamping Rod A tamping rod made of round, straight steel 16 mm in diameter and approximately 600 mm in length,with the tamping end rounded to a hemispherical tip of 16 mm diameter.

13. Shovel / Scoop and Ruler Apparatus

14. Procedure 1 . To obtain a representative sample, take samples from two or more regular intervals throughout the discharge of the mixer or truck. DO NOT take samples at the beginning or the end of the discharge. 2 . Dampen inside of cone and place it on a smooth, moist, non-absorbent, level surface large enough to accommodate both the slumped concrete and the slump cone. Stand or, foot pieces throughout the test procedure to hold the cone firmly in place. 3. Fill cone 1/3 full by volume and rod 25 times with steel tamping rod. Distribute rodding evenly over the entire cross section of the sample.

15. Procedure 4. Fill cone 2/3 full by volume. Rod this layer 25 times with rod penetrating into, but not through first layer. Distribute rodding evenly over the entire cross section of the layer. 5 . Fill cone to overflowing. Rod this layer 25 times with rod penetrating into but not through, second layer. Distribute rodding evenly over the entire cross section of this layer. 6 . Remove the excess concrete from the top of the cone, using tamping rod as a screed. Clean overflow from base of cone. 7. Immediately lift cone vertically with slow, even motion. Do not jar the concrete or tilt the cone during this process. Invert the withdrawn cone, and place next to, but not touching the slumped concrete. (Perform in 5-10 seconds with no lateral or torsional motion.)

16. Procedure 8 . Lay a straight edge across the top of the slump cone. Measure the amount of slump in inches from the bottom of the straight edge to the top of the slumped concrete at a point over the original center of the base. The slump operation shall be completed in a maximum elapsed time of 2 1/2 minutes. Discard concrete. DO NOT use in any other tests. Ruler Slump Slump Cone

17. Slump Test Testing tip : Since concrete setting is time and temperature dependent, this test must be started within 5 minutes after obtaining the composite sample and completed within 2 ½ minutes after the filling process begins.

18. Water-cement ratio [w/c] or water cementitious material ratio [w/( c+p )] The required water cement ratio is determined not only by strength requirements but also by factors such as durability. Since different aggregates, cements and cementitious materials will produce different strength at the same w/c ratio, it is highly desirable to have or develop the relationship between strength and w/c ratio for the materials actually to be used. In the absence of such data, approximate and relatively conservative values for concrete containing Type I portland cement can be taken from table.

19.   Water-cement ration, by mass Compressive strength at 28 days, Mpa Non-air-entrained Concrete Air-entrained Concrete 40 0.42   35 0.47 0.39 30 0.54 0.45 25 0.61 0.52 20 0.69 0.60 15 0.79 0.70 Table A1.5.3.4(a) Relationship between Water-cement Ratio and Compressive Strength of Concrete (SI)

20. Maximum size of aggregate Large nominal maximum sizes of well graded aggregates have less voids than smaller sizes. Hence, concrete with the larger-sizes well graded aggregates requires less mortar per unit volume of concrete. Generally, the nominal maximum size of aggregate should be the largest that is economically available and consistent with dimensions of the structure. In no event should the nominal maximum size exceed one-fifth of the narrowest dimension between sides of forms , one-third the depth of slabs , nor three-fourths of the minimum clear spacing between individual reinforcing bars, bundles of bars or pre-tensioning strands.

21. 31 2 nd test: Making and curing test specimens MAKING AND CURING CONCRETE TEST SPECIMENS IN THE FIELD

22. 32 Apparatus needed :Cylinder mold

23. Apparatus ( Cylinder mold ) We will need the following apparatus for the test. Cylinder mold made of steel 150 mm. In diameter and 300 mm in height constructed in the form of right circular cylinders and the top open to receive the concrete and shall be watertight and sufficiently strong and tough to permit their used without tearing, crushing or deforming.

24. Apparatus ( Beam Mold) Beam mold , rectangular in shape and having a length of 21" . The cross section shall be 6" by 6".

25. Apparatus ( Tamping Rod)

26. 36 Apparatus ( Tools such as shovels, pails, trowels, straight edge, scoop and ruler )

27. 37 Water storage tank

28. 38 Sampling and mixing receptacle

29. II. MAKING AND CURING OF CONCRETE COMPRESSION AND FLEXURE TEST SPECIMENS IN FIELD (AASHTO Designation T 23) (ASTM Designation C 31) For the method of making and curing concrete specimens in the laboratory (AASHTO Designation T126) Molding of (cylindrical specimens) compression test specimens 24” 12” 6” 5/8” Rammer 3 layers 25 blows/layer 1 set (3 cylinders) for every 75 m 3 or fraction thereof, each day of pouring

30. Molding of (Beam) Flexure Test Specimens For Concrete Pavement 21” 6” 6” Beam Specimens A= L x W = 21” x 6” = 126 sq. in. 1 Blow per 2 sq. in. 126 2 blows layer = 63 2 layers 63 blows / layer using the same rammer as in concrete cylinder sample

31. CURING A. Application of water to counteract evaporation Ponding Sprinkling Spraying Wet burlap Wet Earth Wet Sand Saw Dust Straw Application of water proof paper or moisture retention cover sealing curing compound * Continuous moist curing at a temperature range of 15.5 o C – 37.5 o C gives the best results

32. STRENGTH DETERMINATION OF CONCRETE TEST SPECIMENS (AASHTO T 97) Flexural Strength of Beam Specimens a. Third Point Loading Method ////////////// R = P 18 6” x 6” x 6” P in # 12 in 2 = Where: R = Modulus of rupture, psi or Mpa P = Load in lbs. or in tons L = Span length in inches b = base in inches d = depth Specimen L/3 L/3 l/3 1 in Min. D = L/3 Span Length L PL bd 2 =

33. If the fracture occurs in the tension surface within the middle third of the span length. R = PL bd 2 If the fracture occurs in the tension surface outside of the middle third of the span length by not more than 5 percent of the span length. R = 3 Pa bd 2 Where: a = average distance between line of fracture and the nearest support measured on the tension surface of the beam.

34. Example: Flexural Strength using the third point loading Method, FS FS = 2.40 tons x 2204.6 lbs tons X 1 12 in 2 = 440.92 psi FS = 440.92 psi x .006895 Mpa psi = 3.04 MPa

35. b. Center Point Loading Method: L/3 1 in. min. (25 mm) L/2 L/2 Span Length, L R= 3 PL 2 bd 2 Where: R = Modulus of Rupture P = Load L = Span length b – base d = depth

36. STRENGTH OF CYLINDRICAL CONCRETE SPECIMENS (AASHTO Designation T 22) (ASTM Designation C 39) Rate of Loading for Compressive Strength test: Load applied at a constant rate within range 20 to 50 psi / sec. 6” 12” For Cylinder: Cross Sectional Area = IID 2 4 Ac= 3.1416 (6”) 2 4 = 28.27 in. 2 Compressive Strength = 64,000 lbs 28.27 in. 2 X .006895 Mpa psi CS = 15.6 MPa DPWH Spec’s (Blue Book) Compressive Strength requirement – 24.1 Mpa (3,500 psi) Min. at 14 days

37. REINFORCING STEEL BAR

38. – a steel product of plain, round or deformed cross-section for concrete reinforcement REINFORCING STEEL BAR Classification Deformed Steel Bar – surface of which is provided with lugs or protrusions called deformation . Plain Steel Bar – without surface deformation Grade - Steel bar shall be graded according to its minimum yield strength Length – available at 5.0, 6.0, 7.5, 9.0, 10.5 and 12.0 meters Sizes - 10mm, 12mm, 16mm, 20mm, 25mm, 28mm, 32mm, 36mm, 40mm and 50 mm in diameter Grade 520 (75) bars are furnished only in sizes through 18 (19 mm through 57 mm) Grade 280 (40) bars are furnished only in sizes 3 through 6 (10 mm through 19 mm)

39. Uses Embedded in concrete for purpose of resisting particular stresses Control cracking of concrete structure Maintain the structural integrity of the slab between transverse joints Prevents the progressive opening of cracks by holding the edges of the cracks closely together

40. Sampling/Minimum Testing Requirement One (1) (Q.T.) for every 10,000 kgs or fraction thereof for each size Test Specimen : 1 – meter representative of the size of steel bar intended for test. mark in the center of the test specimen a 200 mm ( 8 “ ) gage length. Testing Equipment : Universal Machine - main equipment having 100 tons or 200,000 lbs. capacity Quality Test (Q.T.)

41. TESTS ON REINFORCING STEEL BARS 1. Variation in Mass The test determines the actual size of the bar based on weight Measurement per one-meter length and determines its variation to the standard nominal mass per respective size of the steel bar Actual Mass of Specimen, kg/m - Nominal Mass, kg/m x 100 Nominal Mass, kg/m Variation in Mass, % : Shall not exceed 6% under nominal weight except for bars smaller than 3/8 in. (10 mm) plain round. In no case shall the overweight be the cause for rejection. Variation in Mass, % : DPWH Specification:

42. Weight measurement per meter length of steel bar

43. 2. Determination of Tensile Properties The test is intended to determine the yield and tensile strength of the bar as well as its elongation, and is used to classify the bars into grade. Tensile Strength = _____________”________________________________ Maximum Load the Specimen sustains during test Nominal cross-sectional Area of the Specimen Yield Point = _____________________________________________ Load sustain by the Specimen by the sudden halt of Load Nominal cross-sectional Area of the Specimen

44. STANDARD SPECIFICATIONS FOR DEFORMED AND PLAIN STEEL BARS FOR CONCRETE REINFORCEMENT AASHTO M 31 ( 2003 ) Grade Tensile Strenght , MPa, min. Yield Stenght , Mpa, min. 280 ( 40 ) 420 280 420 ( 60 ) 620 420 520 ( 75 ) 690 520 Elongation Requirements: Strength Requirements: Bar Designation No. / mm Grade 280(40) Grade 420 (60) Grade 520(75) No. 3 ( 10 ) 11 9 - No. 4, 5 ( 13, 16 ) 12 9 - No. 6 ( 19 ) 12 9 7 No. 7, 8 ( 22, 25 ) - 8 7 No. 9,10,11 ( 29, 32, 36 ) - 7 6 No. 14, 18 ( 43, 57 ) - 7 6

45. Bending Requirement No cracking on outside bent Variation in Mass, % 6.0 Max. under nominal mass Phosphorous Content, % 0.06 Max. Footnotes: Grade 280 (40) are furnished only in sizes from 10 mm through 19 mm Grade 420 (60) are furnished in all sizes from 10 mm to 57 mm Grade 520 (75) are furnished only in sizes from 19 mm through 57 mm 55

46. GRADE MINIMUM TENSILE STRENGTH, Mpa MINIMUM YIELD STRENGTH, Mpa Non - Weldable Weldable Non - Weldable Weldable 230 390 390 230 230 275 480 480 275 275 415 620 550 * 415 415 ** Elongation Requirements: GRADE BAR DIAMETER, mm PERCENT ELONGATION NON – WELDABLE WELDABLE 230 < 25 mm 18 20 275 < 25 mm 10 16 ≥ 25 mm 16 18 ≥ 25 mm 8 14 425 < 25 mm 8 14 ≥ 25 mm 7 12 PHILIPPINE NATIONAL STANDARD PNS 49: 2000 SPECIFICATION FOR STEEL BARS FOR CONCRETE REINFORCEMENT Strength Requirements:

47. PHILIPPINE NATIONAL STANDARD PNS 49: 2000 SPECIFICATION FOR STEEL BARS FOR CONCRETE REINFORCEMENT Dimensional Properties Parameters Nominal Diameter, mm 10 12 16 20 25 28 32 36 40 Nominal Unit Mass, kg/m 0.616 0.888 1.578 2.466 3.853 4.834 6.313 7.990 9.865 Nominal X-Sect. Area, mm2 78.54 113.10 201.06 314.16 490.88 615.75 804.25 1017.88 1256.64 Max. Ave. Spacing, mm 7.0 8.4 11.2 14.0 17.25 19.6 22.4 25.2 28.0 Min. Lug Height, mm 0.4 0.5 0.7 1.0 1.2 1.4 1.6 1.8 2.0 Max. Summ. Of Gaps, mm 7.8 9.4 12.6 15.7 19.6 22.0 25.1 27.5 31.41 Max. Lug Height, mm 0.8 1.0 1.4 2.0 2.4 2.8 3.2 3.6 4.0 Variation in Mass, % ± 6 ± 6 ± 6 ±6 ± 6 ± 6 ± 6 ± 6 ± 6 Note : * Tensile srength shall not be less than 1.25 times the actual yield strength. TS / TY for Weldable ≥ 1.25 ** Yield Strength = 540 Mpa max.

48. TENSILE STRENGTH DETERMINATION OF REINFORCING STEEL BARS

49. Elongation, % : Final Elongation, mm – Gage Length, mm x 100 Gage Length, mm 3. Elongation : express as the increase in length of the gage length as a percentage of the original gage length. Measurement of rebar elongation Elongation, % : See Table (Based on the size of steel bar) DPWH Specification:

50. 4. Phosphorous Content Determination The test evaluates the ductile properties of rebars Phosphorous Content, % = DPWH Specification: 0.06 Max

51. 5. Deformation Measurements (For deformed Bar) Average spacing (spacing between the lugs) Average Height (Height of the lug) Gap (Width of the Rib) Measurement of rebar deformation

52. Reporting : Examine carefully the bent portion for any sign of cracking on the outside bend and report with satisfactory when no cracks appears and unsatisfactory when sign of crack occurs. The test is one of the methods in evaluating the ductile properties of the reinforcing steel bars. 6. Determination of Bending Properties Set cold bend apparatus then place sample for bending test Start the bending operation using Universal Testing Machine (UTM)

53. A slump Cone use to test freshly mixed concrete is a mold in the form of lateral of lateral surface of the frustum of a cone with a base diameter 8” and a top diameter of 4”. What is its height? 6” 8” 12” 24”

54. It is the most important component in determining the strength of concrete Cement Water Sand Gravel

55. The most important factor affecting the strength of concrete Void – Cement Ratio Water Quantity of Cement Water- Cemenr Ratio

56. When do you get samples for a Slump Test? At the start of mixer discharge At the middle of mixer discharge At the end of mix At any time of mixer discharge

57. Reinforced Concrete Design

58. BEAMS

59. Ultimate Load = Reduction factor x Nominal Load Ultimate Capacity = Reduction Factor x Nominal Capacity

60. Strength Reduction Factors F( Phi) A. Flexure without axial . . . . . . . 0.90 Axial tension, and axial tension with flexure . . . . . 0.90 Axial Compression, and Axial Compression with Flexure A. Spiral . . . . . . . 0.75 B. Ties . . . . . . . 0.70 Shear and Tension . . . . . . . 0.85 Bearing on Concrete . . . . . . . 0.70

61. Balanced Section The steel provided in the beam is such that both concrete and steel reach the limiting values of strain simultaneously. Analysis and Design of beams

62. Steel ratio r = As/ bd r max = . 75 r bal r min = 1.4/ fy Ratio of tension reinforcement *For flexure members, it should not exceed .75 of r balance *and not less than 1.4/ fy

63. Under Reinforced Section The steel provided in the beam is such that steel reach the limiting values of strain prior to concrete. This results in yielding of the steel and the steel could yield till it attains the ultimate strain at which point it breaks. Analysis and Design of beams

64. Over Reinforced Section The steel provided in the beam is such that concrete reach the limiting values of strain prior to steel. This results in breaking of concrete and since now there is no concrete present to take the compression the beam fails suddenly. The additional margin that we get in under reinforced section helps in prevention of a sudden failure and provide the necessary warning to the inhabitants of the building. Analysis and Design of beams

65. Singly Reinforced Beam Singly reinforced beam is one in which the main reinforcement is provided only in the tension zone and also here the ultimate bending moment is less than the limiting bending moment.

66. Doubly Reinforced Beam Occasionally, beams are restricted by space or aesthetic requirements to such extent the compression concrete should be reinforced with steel to carry compression.

67. T- Beam Reinforced concrete floor usually consist of slabs and beams, which are placed or poured monolithically. In this effect, the beam will have an extra width at the top (that is under compression) ca;; ed flanges.

68. Mu = Moment Capacity of beams

69. Shear Reinforcements

70. Shear Reinforcements Another type of beam failure other than bending failure is shear failure. Shear failures are very dangerous especially if it happens before flexure failure because they can occur without warning

71. Type of Stirrups

72. The design of bending members for shear is based on the assumption that concrete resist part of the shear and any excess over and above what the concrete could carry should be resisted by shear reinforcement which may take in several forms. Vertical stirrups Inclined or diagonal stirrups; and The main reinforcement bent at ends to act as inclined stirrups

73. Type of Shear Reinforcement According to Section 5.11.5.1 of the Code, shear reinforcement may consist of Stirrups perpendicular to axis of member, and Welded wire fabric with wires located perpendicular to axis of member

74. Exceptions Shear reinforcements shall be provided in all reinforced concrete flexural members except as follows: 1. slab and footings. 2. beams with any of the following: a total depth less than 250mm, 2.5 times the flange thickness or ½ the width of the web, whichever is greater. 3. in concrete joist construction 4. where Vu <  

75. Criteria Equations φVc = φ 1/6 Vc = shear force that concrete alone resists b = width of rectangular beam or =width of web for a T-beam d = effective depth of beam Φ = strength reduction factor = 0.85 Vu = (for simply supported beams)  

76. Spacing of Stirrups S = Vs = Vu/ φ – Vc Vs = Vn – Vc = nominal shear strength provided by the shear reinforcement Vn = Vu/ φ Vc = 1/6 when Vu > (needs stirrups)  

77. Spacing Criterion Smax = d/2 600mm if Vs 1/3 Smax = d/2 if Vs > 1/3 Smin > 2/3 Smin = 75mm or 100mm  

78. Minimum area of web reinforcement Av = Av = 2As = (for 10mm φ stirrups) b = width of rectangular beam or = web width for T-beams S = spacing of stirrups center to center (mm) fy = yield strength of web reinforcement  

79. min(   Development Length

80. Development Length Bar development length or Ld is the embedment necessary to assure that the bar can be stressed to its yield point with some reserved to insure member toughness

81. Basic Development Length of Bars For 32mm and smaller For 36mm For deformed wire  

82. Clear Cover

83. Sample Problems What is the minimum concrete cover of cast-in-place 2ndfloor slabs considering 42mm dia bars??

84. 40 mm

85. Sample Problems What is the minimum concrete cover of cast-in-place slab on fill considering 16mm dia bars?

86. 75 mm

87. Standard Hooks

88. Sample Problems Given a 300mmx300mm Column with a 8-16mm dia main bars and 10mm dia. Ties, what is the length of each column tie if the column is nonprestressed and not exposed to weather?

89. Given a 300mmx350mm Column with a 8-20mm dia main bars and 10mm dia. Ties, what is the length of each column tie if the column is nonprestressed and not exposed to weather? Sample Problems

90. COLUMNS

91. Tied columns

92. Spiral Columns

93. General Specification Minimum cross-section 200 X 300 mm Minimum Gross Area 60000  

94. Axial Load Capacity Where = Nominal Strength = Ultimate Load = Reduction Factor = Concrete Strength = Gross area of the Column = Area of Steel  

95. Reduction Factor For Tied Column = 0.80 = 0.70 For Spiral Column = 0.85 =0.75  

96. Longitudinal bars 0.01Ag < Ast < 0.06Ag  

97. Lateral Ties and stirrups 10 mm - Longitudinal bars with 32mm or smaller 12mm - Longitudinal bars with 36mm or larger and for bundled Longitudinal bars

98. Spacing of Lateral Ties The spacing of these ties shall not exceed: 16 longitudinal bar diameter, 48 tie bar diameter or the least dimension of the compression member.

99. Spirals For Cast-in-place, Minimum size is 10 mm Ratio of Volume of Steel to Volume of Gross area is derived by the equation: Minimum ratio can be derived by:  

100. Spacing of Spiral Ties Minimum Spacing of Spirals is 25mm Maximum Spacing of Spiral is 75mm

101. THANK YOU!!