slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. Unit weight for feet per metre = (D2/ 533). 11*12 in c/c Step 6 : Temperature and Shrinkage ReinforcementWeight of distribution of 8 mm dia steel bar = 33. 4. For a 6 in. 7. (Main Bar & Distribution Bar Difference) Top and Bottom Clear Cover is 25 mm. Head of Chair: Length of head = (2 * spacing of distribution bar) + (2 * 50) = (2 * 150) + (2 * 50) = 400mm. 667’ x 40. 3. In Seismic Design Categories D 0, D 1 and D 2, slabs-on-ground cast monolithically with turned-down footings shall have not fewer than one No. If the maximum diameter for. 2: Alternate method for showing two-way slab reinforcement reinforcing bars should be clearly scheduled on the drawings. Distribution Bar. 2 BS 8110-1:1997) Width of the beam = 500mm = 0. c. and the clear spacing between the bottom bars a = 60 mm. Two way slab building. Self-weight of the slab = 3. 12. 5d or 450 mm whichever is smaller for distribution steel. 2 shall be provided between the ten-dons at slab edges extending from the slab edge for a dis-tance equal to the tendon spacing. Concrete cover to main reinforcing bars shall be provided per AASHTO Table 5. Exceeding a joint spacing of 15 ft. slabs, walls, and joists - #14 and #18 bars - ½ inch; Slabs, walls, and joists - #11 bars and smaller - ¾ inch ; Beams and columns. The maximum spacing of bars shall not exceed. Bar Spacing. 5. = constant used to compute V c in slabs and footings. 7. 1—Early-age concrete material strength development 4. how to calculate the number of rebar in an exceedingly circular block. 21. The spacing of distribution bar should not be greater than 5 times the effective thickness of slab or 450mm whichever is smaller. 3. Design the slab using the data given below; Purpose of building – Residential. 0146. 4 Deck Overhangs for guidance on deck slab bars. 3) or the distance of centre of gravity of the concentrated load from the nearer support (ci. Base slab width b= 0. The minimum eccentricity values as per IS 456 code provision is calculated by using below formula in the column design we need to consider minimum or greater than 20 mm value as eccentricity value. W = 3. bar due to its non-availability. To firmly hold the main bars in their. 18% of gross sectional area (B×D), taking B= 1m width of slab and D= overall depth including cover, then minimum reinforcement will be = 0. Main Bars and Distribution Bars in Slab and Their Function. 75 m. The distribution bars provide the following functions in slab construction: 1. 8. assume corners are held down. 42D) – (1d x 4) – (2d x 2 (From BBS shape codes) d = diameter of the bar. 9) Prepare bar bending. The spacing or c/c distance of distribution bars shall not exceed the following. The Distribution bars will be 8 mm in diameter @125mm c/c spacing. 2 Symbols Relating to Shape of the Bar Along Its Length As per IS 456: 2000, Cl. 1. Calculation of the loads. 7 For temperature steel only, maximum spacing shall not exceed five times the slab thickness h nor 450. , i. 7. For Min Steel: 3d ——— Where. 7. The reinforcing bars must extend into the slab beyond the critical section for a required length. This chapter shall apply to the design of nonprestressed and prestressed beams, including: (a) Composite beams of concrete elements constructed in separate placements but connected so that all elements resist loads as a unit. It brings economy to the design of. (b) One-way joist systems in accordance with 9. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. Check spacing of bars. , Chapter 12 c c = clear cover of reinforcement, in. s code Sandeep Yadav. The main conclusions can be summarized as follows: • The proposed method gives a good estimate for crack. than that calculated as per Sections 12 and/or 16 (whichever is higher) of IRC:112. 6—Reinforcement limits 8. M =. Consider the ACI 318-14 code according to which the Ø is the strength reduction factor as specified in table 21. steel bar on top of wall. The minimum cover for cast-in-place concrete is specified by the ACI 318 Building Code. The shear resistance in a R. Minimum number of bars for a square column are 4 and for circular column are 6. 1. This spacing should be reduced by a factor of 0. #IScodes #Concrete #Concretetechnology Recent & Related Videos Concrete. of bars = { (L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. STEP. Conclusion. 7. 5—Application of the simplified method 3. Distribution bars placed on top of the main bar. 3 Required Strength 4-2. . where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. They ensure that the load is not concentrated in one area, which could cause cracking or failure. Now assume diameter of bars and calculate spacing between bars. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. If the reinforcing bars do not extend beyond the critical section. 5 M from the edge of wall and at both ends 6 mm plain M. dia. 10. 26. cb = smaller of (a) the distance from center of a bar or wire to nearest concrete surface, and (b) one-half the center-to-center spacing of bars or wires being developed, in. 1. 1 or the bottom bars required by 8. Calculation of number of distribution bars. Use #4 bars at 25-inch spacings center to center each way, As = 0. for a 6 in. of bars= (Slab length (L)/spacing)+1 Equation 1. Ld = Development length of the bar. 1 of IS 456), the maximum spacing is the lesser of 3d and 300 mm i. 167 for 15% redistribution. BS EN 1992–1–1 section 6. The maximum clear spacing between parallel bars shall not be more than 1 N-6O. 6% of the gross wall area for Grade 60 or Grade 40 bars, respectively. 7. 8. In this article I will explain you complete slab design as per IS 456 code by using manual method. 2 to read as follows:Top & bottom distribution bar dia. 4 Spacing Between Longitudinal Bars. TWO WAY SLAB DESIGN SPREADSHEET:Fig 10: Reinforcement of a slab. 5 In walls and one‐way slabs the maximum bar spacing shall not be more than three times the wall or slab thickness h nor 450 mm. 3 times effective depth c. 3. 4. There is two spacing between 3 reinforcement and 50 mm length both side of 1st and 3rd reinforcement used in footing. D. Total No’s of Distribution Bars = (Total layers of Dist Bars in Walls are 4) = 10 x 4 = 40 No’s Total Length of Distribution Bars = Cut Length x No’s of Bars. 7. reinforcing parallel to load per inch of slab width perpendicular to load / slab thickness) (steel yield stress)) f. 167, hence it is singly reinforced. 090 square inches per foot of slab width, required each way. 2) The horizontal distance between parallel reinforcement bars provided against shrinkage and temperature shall not be more thanACI 360R-102 is a major resource covering design of slabs-on-ground. 5] = 120 mm c/c. 1 Answer. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm. 25 in. How to Design Concrete Structures to Eurocode 2 - Chapter 7 : Flat slabs and Figure 6. 096 square inches per foot (or #4 bars at 18 inches center to center to meet ACI criteria, As = 0. The clear cover is 30 mm ( top to bottom ) and the thickness of the slab is 150 mm. (b) 18 in. This is needed both to prevent splitting of the con-crete adjacent to the stud and to allow load to spread out across the width of the slab. 3. 15% for Mild steel bars. 3. For distribution bars, the maximum spacing is specified as 5 times the effective depth. Height of block wall = 2. e. Concentrated reinforcement is a fixed number of bars over a parallelogram area. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 3. 14 x 5 x 5 = 78. 12. There are 51 nos of main bars are required for the slab. In this article, we will develop a Slab Design Example using the last version of ACI-318-19: “Building Code Requirements for Structural Concrete,” consisting of the modeling in SkyCiv of a Reinforced Concrete Low-Rise Building focusing on the comparison of software results and hand calculations by an accepted method by ACI: “The Direct Design Method for. ( IS: 456-2000 ). The Main. In general we use 5 inch (125mm) thick slab, if thickness of slab is 125mm,then maximum diameter of bar used in. 96 x 1000 / 1536 = 130. BS EN 1992–1–1 section 7. bar per corner 10mm Ø vert. The code makes it explicit that the diameters of the skin bars are not involved in determining the spacing of this reinforcement. To distribute the superimposed load to the main bar. 7. Maximum spacing should not exceed the lesser of 20 x size of the smallest compression bar or the least lateral dimension of the column or 400 mm. per 18-in. 460/2=1. Top & bottom distribution bar dia. M255M/M 255 (2019) Standard Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties M 334M/334 (2017) Standard Specification for Uncoated, Corrosion-Resistant, Deformed and Plain Chromium Alloy, Billet-Steel Bars for Concrete Reinforcement and Dowels T 253-02 (2016) Standard Method of Test for Coated Dowel. c 0. 66 < 2. Ensure a minimum number of bars in a square column is 4 and in a circular column, 6. The slab has to carry a live load of 4 KN per meter square. Thus, the requirement threshold of 125psi (0. Reading time: 2 minutes. Business, Economics, and Finance. (15) Step Spacing of the dowel bars. 1. 12. In general, the main bars are usually placed parallel to the shorter dimension of the slab to reduce the slab's overall span length and provide. Weight of Distribution Bar= (8)²/162. No of main. In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. Given data: Distribution bar dia. Calculation of number of distribution bars. 1. 5, the lateral spacing of the. According to ACI Code 7. Now we have to calculate the depth from maximum moment values. The spacing of the lateral ties is 100mm to 200mm for safe structure design. The slab is. Step Find the length of the dowel bar embedded in slab by equating Eq. (ii) The pitch of the bars provided to act as distribution bars or bars provided to guard against temperature and shrinkage in an R. 18% of gross sectional area (B×D), taking B= 1m width of slab and D= overall depth including cover, then minimum reinforcement will be = 0. 31kg says 35kg. 5. Figure: Contraction joint;. f ck = 25 Mpa. In general we use 5 inch (125mm) thick slab, if thickness of slab is 125mm,then maximum diameter of bar used in slab is 125/8 which is equal to 16mm. Total Load on Slab (Dead Load + Live Load +Wind Load + Self-Weight) Besides this above loading, the columns are also subjected to bending moments that have to be considered in the final design. The manual design process included the reinforcement calculation for the main. Reinforcement Cover The minimum cover to outside of main bars shall not be less than the following: 15 mm and; Diameter of the main bar. properly jointed slab. 3 Direct supply of steel reinforcing bars to site by QA Manufacturer 27 Section 5 Purchasers testing 28 5. 7. Clause 6. 6 𝑀𝑃𝑎. 3(d) and 17. 9. 10mm Main Bars @ 150mm C/C spacing; 10mm Distribution Bars @ 200mm C/C Spacing; Development Length L d = 40d; Top Extra Bar 8mm @ 150 mm c/c (both direction) Bar Bending Schedule for Two Way Slab. Step 5 – Calculation of Steel Weight. 5 and 6. b. The Distribution bars will be 8 mm in diameter with 125 mm c/c spacing. tangential spacing of legs of links, st max. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. Cutting length= length of retaining wall – 2 x concrete cover. (2× Spacing of distribution bar) + (2×25) = (2 x 150) + ( 2 x 25) = 350 mm . The maximum spacing should be reduced by a factor of 0. 7. 5, which equals 51. 3. , the effective depth is: clear spacing between layers clear cover stirrup diameter bar diameters 2 dh . in. *A4 size is 210 x 297 mm. c) Spacing of bars: The maximum spacing of bars shall not exceed Main Steel – 3d or 300 mm whichever is smaller; Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. Full bond Full bond h/2 Filler Figure 15:3: Contraction joint 15. Tayabji (1986) identified the following categories of dowelmillimetres and N represents the identification number of the bar/bars given consecutively. Diameter of main bar=10mm. design wheel load. 2—Construction load factorsThe diameter of the main bar should not be less than 8mm for the HYSD bar and 10mm for plain bars. ratio of flexural stiffuess. 6. Here, ∅ is the bar diameter. Step 1. Dowel bars require care in placement to minimize. Calculate The Cutting Length of the Chairs Bar Given Data. 3 introduces a new requirement for barBridge Deck Slab Design Example as per IRC Indian Codes, Deck Slab Bridge Design are described step by step by Using Limit State Method. bars at every 3 layers of chb finished surface wall intersection b h lintel beam reinf. R403. Provided to resist the bending stress. Distribution steel –5d or 450 mm. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. Effective depth=d provided =120-20-4= 96 mm. Figure 3. 4 Minimum Eccentricity Step 5: Calculation of Steel Weight. 5. . 2, with “S” assumed to be equal to the length between negative moment design sections. 975 KN)/ (39. 2. 300mm. 2. Weight of rod per meter length = d 2 /162 where. 7. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. For example let us consider a building which is having 120mm thickness of slab, for that particular structure we need to take maximum reinforcement bar diameter is (1/8) of 120mm which is 15mm. Clear Cover = 20 mm. The max. Number of bar = total width /spacing +1. 2. The design method is followed as per Annexure D of IS 456:2000. The maximum spacing of minimum steel (distribution bars) is the lesser of 5(135) and 450 mm. the joint spacing should be 24 to 30 times the pavement thickness with a maximum spacing of 15 ft (4. 5% or 0. The number of bars is 50. The dowel bars are provided in the direction of. 97 kN/m 2. 1: The prime functional requirement of a joint is to cater for movements with very low resistance or with no resistance at all. 7. There are also new provisions for integrity reinforcement. 5% steel (continually reinforced) as described in Section 8. 2 – Spacing of tendons shall not exceed 6 feet. f yk = 460 Mpa. Provided at the bottom of the slab. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 33=16 no’s. 1000 1500 2000. The ideal spacing for these bars is around 18 to 24 inches on center (from the center of one bar to the center of the next), depending on the expected loads and local building codes. Now. 096 square inches per foot (or #4 bars at 18 inches center to center to meet ACI criteria, As = 0. Wood structural panels with a minimum thickness of 7 / 16 inch (11. Distribution Reinforcement) Class B (Not Top Bars) J, NThe span requirement for the slabs is given by ACI Code 8. Curtailment of bars in slabs Curtailment of bars is. D = Height of the bending bar. For instance, the ACI 318-19 specifies minimum slab thickness that satisfies deflection. 6 in the following cases; In sections within a distance equal to 4 × thickness of wall above or below a beam or slab. 5. 2 of IS 456) shall not exceed 140/8 = 17 mm is also satisfied with the bar diameters selected here. Spacing = 150mm c/c as per given details = (6000/150) + 1. Reading time: 2 minutes. 5. R-5 insulation shall be provided under the full slab area of a heated slab in addition to the required slab edge insulation R-value for slabs. 12. 2), The bar spacing shall not exceed 450 mm at any location (ACI Code Section 7. , B. Step 2 – Calculation of Cutting Length. The Main bars will be 12 mm in diameter with 100 mm c/c spacing. 2, also includes guidance on achieving enhanced aggregate interlock by continuing a small percentage of deformed reinforcement (0. Cryptocritical section of the slab is just outside the outside edge of the beam supporting the slab. 6—Factors affecting the construction load distribution 3. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. 3). Diameter of Distribution Reinforcement Bars = d d =12mm. Additionally, the clear space between the transverse bars and lapped bars may not exceed 1. 4. What Is The Maximum Bar Spacing In Slab As Per IS-Code? In the case of the RCC slab, the maximum spacing between the two parallel main reinforcement bars should be 3D or 300 mm or whatever. Having <0. Slab steel bar spacing maximum 150mm c/c. In both cases, the minimum bar areas are equal to 0. Longitudinal reinforcement should not be less than 0. 5. 1 Conditions of test specimens 32ACPA Guide Specification | Dowel Bars for Concrete Street and Highway Pavement | ACPA M254-21a August 1, 2021 | Page 4 of 12 2. 6 = 17 bars; The number of distribution. 6. On the bigger side, distribution bars are supplied, however, they will not assist in bearing any weight. 10mm Ø hor. 3, the maximum spac- c) Spacing of bars: The maximum spacing of bars shall not exceed Main Steel – 3d or 300 mm whichever is smaller Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. 7 Storageof MaterialsThere are 2 types of bars in two-way slab: Main Bar & Distribution Bar; Main Bar Diameter = 10 mm; Spacing Between Main Bars(C/C distance) = 150 mm; Distribution Bar Diameter = 8 mm; Spacing Between Distribution Bars(C/C distance) = 100 mm; Length of Slab = 6000 mm; Width of Slab = 3000 mm;. 4 Deck Overhangs for guidance on deck slab bars. NOTATION All notations and definitions are the same as defined in Chapter 2 of the Code. 3. 2. bars at 400 mm o. 6. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. Head ( E ): The length of the head = [(2nos. 5. 3. 9. 2. A minimum of three bars evenly placed in the lap length is required. Two way slabs Since our typical floor slab is symmetric in two directions, we analyze only a representative section for moments and their adjustments, as shown below. 3. BS EN 1992-1-1 Annex 1 1. The spacing of distribution bar should not be greater than 5 times the effective thickness of slab or 450mm whichever is smaller. 75H for surcharged wall. The transverse bar must be No. They ensure that the load is not concentrated in one area, which could cause cracking or failure. 2 (8) Beams: the maximum transverse spacing of the legs in a series of shear links s t,max; 9. This spacing should be reduced by a factor of 0. 2, or >0. Bars shall not be smaller than No. If we increase the spacing beyond 200mm the column section buckling effect will occur. These bars should be distributed as evenly as possible between the negative moment design sections, with one bar being placed at the inside of each bottom truss bar bend. Distribution Bar = width of the foundation – 2 CC ÷ Spacing +1. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. Distribution Bar. Spacing between bars = 0. The AASHTO-LFD formulas are based on the girder spacing only and are usually presented as S/D, where S is the spacing and D is a constant based on the bridge type. 3. Number of Required Bars Formula = (Length of slab / spacing) + 1. 12, apply only to one-way slabs (all code sections cited hereinafter are from ACI 318-08): “7. 200= 6. Reinforcement details bay C-D, 1-2. t + d Lsy. 3. MOM-X – Longitudinal moment, corresponding to which LONG. 3 through the column, at least two post-tensioned tendons or two bonded bottom bars or wires in each direction shall pass through the lifting collar as close to the column as practicable. Modify ACI 318 Sections 17. 5 m as per IRC. 3. Number of Main Bar & Distribution Bar: First, we have to calculate the number of bar required for the slabs. A diagonal crack that might result in shear failure, as suggested in Fig. Important Points. The main bars will be 12 mm in diameter @100 mm c/c spacing. Minimum clear cover to reinforcements in slab depends on the durability criteria and this is. EXAMPLE PROBLEM 1. c) Spacing of bars: The maximum spacing of bars shall not exceed Main Steel – 3d or 300 mm whichever is smaller Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. áTie the bars at the top and the bottom irrespectively. Bar Spacing: The lateral spacing of the flexural bars should not exceed 3 times the thickness h or 18 inches according to ACI code 7. 25 kN/m 2. Sub-Grade and. Distribution Reinforcement for Stairs. 5 Loads on Supporting Beams 25 COMPRESSION MEMBERS 25. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. Development length = 40d. as per ACI 318. Basically slab is the horizontal member which is rests on the beam section. The quandary with composite slab roofs is that a composite slab provides higher shear strength, but it also adds mass to the system thereby increasing seismic forces. According to direct design, the balanced load, W1, and the effective prestressing, F, in a one-way slab or the beam supports for one-way slabs can be computed as t _ 48kBW + 8k f (L (3) Wl — 1 + 48kB F, = 72BW L2 + 12 f t2 (4) t(1 + 48kB) where B is the moment coefficient, M = BWL2, depending on the slabDesign of 2 way slab as per IS code.