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. For distribution bars (cl. As discussed earlier, assume that the beam is reinforced with two layers of #11 reinforcement and clear spacing between layers = 1 in. 7. 4 MoVEMEntS And rotAtIonS: 4. Dual degree in Civil Engineering, and M. Concrete Slab Design ProcedureSteel reinforcements can be use, however with a maximum spacing of 4. Step 1. 2 of IS 456 :2000 , the reinforcing bars shall not exceed 1/8 of theHow to Design Concrete Structures to Eurocode 2 - Chapter 7 : Flat slabs and Figure 6. 2 d t kips in. 1 mm) and maximum panel span of 8 feet (2438 mm) shall be permitted for opening protection in buildings with a mean roof height of 33 feet (10 058 mm) or less that are classified as a Group R-3 or R-4 occupancy. The span requirement for the slabs is given by ACI Code 8. 1. Note * Spacing rationalised to suit punching shear links. = 175 mm Last perimeter, from column face, min. i = 100-yr. 6. bar per intersection 10mm Ø vert. 3. Spacing Requirements. 2 times effective depth b. NOTE 3 - In co1 3. 7. 15%of gross cross-sectional area if plain bars are used and 0. Distribution bar 8 mm C/C 140 mm Length 1. 9) Check for shear ( using Table 19 of code IS 456:2000). The equivalent of closer-spaced, typical slab bars can be achieved f DESIGN of ONE-WAY SLAB based on NSCP 2015 and ACI 318-14. unless otherwise noted, all slabs on grade are to be reinforced with 10mm bars at 400mm o. IF Grade 50 to 60 deformed bars or welted wire reinforcement are used9. 12. Minimum number of reinforcing bars. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. Unit weight of concrete = 25 kN/m 3. 460/2=1. 2. (1) Deformed steel bars will be overlapped for a distance of at least 24 bar diameters measured from the tip of one bar to the tip of the other bar. 5bw and 600 mm B. 3. This type of reinforcement is convenient for modeling beam reinforcement. 3 Slenderness Limits for Columns 25. 7. 7. The use of #4 or #5 bars is at the discretion of the Structural Project Manager if both available diameters meet demand. 13. 18D sq. 10. 2—Construction load factorsThe diameter of the main bar should not be less than 8mm for the HYSD bar and 10mm for plain bars. a) Slab depth does not exceed 250mm when the steel grade is 250. 230m. Special surface finishes, including coatings. 3. bars in two-way slabs. 11in2) Spacing = As 0. 2. of main bars = Lx/Spacing + 1 = 5000/150 = 34. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. Distribution bars:-These bars are straight bars. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. 2. Bar Bending Schedule Of Slab (Two Way) Ly/Lx = Longer span/Shorter span = 5000/3000 = 1. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. That is: 19′. Step 1. Provided to resist the shear stress and cracks. In RC slabs and PT one-way slabs, the clear distance between bars is limited to the smaller of. 5d or 450 mm whichever is smaller for distribution steel. No of bars = (opp length/spacing) + 1. So we have total 16 nos of distribution Reinforcement bar so the total length is. The Clear cover will be 25 mm (Top or Bottom) and the thickness of the slab will be 150 mm. 3 For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall ‘be rounded off in accord-Table 5. AS3600-2009 P P Lsy. The main reinforcement of an RC slab consists of 10 mm bars at 10 cm spacing. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. 14 x 5 x 5 = 78. Ensure a minimum number of bars in a square column is 4 and in a circular column, 6. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. Number of bar =radius of slab/spacing. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Here we have to calculate the number of main bar and distribution bar. Grade of concrete ƒck, Grade of Steel ƒy, Concrete cover, Clear long spam, Clear short spam, With of supporting beam, Live load, Floor finish load, The diameter of the main and distribution bar, and; Assume the. length of. 1 QA Stockist’s certification of steel reinforcing bars 25 4. Diameter of top and bottom main bars = 20 mm. Near lapped joints, if the diameter of the longitudinal bar is greater than 14 mm. 3. 3. BS EN 1992–1–1 section 7. (b) One-way joist systems in accordance with 9. This is also satisfied for all the bars. Clear cover = 25mm (top and bottom ) Thickness = 150mm. 11. 6. The spacing or c/c distance of distribution bars shall not exceed the following. 8. 18D sq. 10. Diameter of main bar=10mm. 5d = 5 * 130 = 650 mm. Weight of Distribution Bar= (8)²/162. Check spacing of bars. 12 % of the gross area if the HYSD bar (Fe415) is used. Distribution bars typically have lesser dimension bars compared to main bars. 5. 900 m. ,). 6m . Check resistance to moment transfer from column to slab . 2. 2, or >0. , 300 mm. 8. 5. 5—Application of the simplified method 3. slabs, walls, and joists - #14 and #18 bars - ½ inch; Slabs, walls, and joists - #11 bars and smaller - ¾ inch ; Beams and columns. Step 5 – Calculation of Steel Weight. b) For design of distribution bar/Transverse bar. 2 Symbols Relating to Shape of the Bar Along Its Length As per IS 456: 2000, Cl. . Main Steel – 3d or 300 mm whichever is smaller. ment among different types of cements. 2 or 8. How to calculate reinforcement bar spacing How to calculate Minimum Bar Spacing for Bundle Bars in Cast-in Place Concrete as per AASHTO provisions. ( IS: 456-2000 ). 3. 2 SlabsContinuous OverSupports 24. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. however with a maximum spacing of 4. ACI 318-19, Table 8. exposed to earth or weather. This spacing should be reduced by a factor of 0. 25 x total length of bar. Distribution Bars= (Total length of the slab – 2 x clear cover)/center to center spacing of the bars + 1; Distribution Bars = (2000- 2 x 25) /125 +1; Distribution Bars = 16. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. slab, shall not. 6. The Department of Civil Engineering at IIT Kanpur is producing since 1961, high quality technical manpower needed by industry, R&D organizations, and academic institutions. BS EN 1992-1-1 Annex 1 1. (b) Horizontal reinforcement at least 0. 5 m. 26. Main bar = 12mm@150mm c/c. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. As per IS 456: 2000, Cl. Main Reinforcement bars are placed in shorter direction and Distribution bars placed in longer span direction. 6 Reinforcement 5. 3. Every alternate bar is cranked up to 0. Minimum requirement in slab : As per clause 26. Ex. 7. “D” bars (Distribution bars) - Longitudinal bars in the bottom mat of deck reinforcement. 1. 2—Flexural reinforcement spacing 8. 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. Here, ∅ is the bar diameter. 33(fc') 0. 091 = 300. 2. One Way Slab Bar Bending Schedule Calculation. Bar cranking is the process of bending up the bottom steel bars in upward direction. Reinforcement chairs should be made with a minimum of 12 mm bar. spacing of 18” d) Choose bars: For square footings use the same size and number of bars uniformly spaced in each direction (ACI 13. The maximum spacing of minimum steel (distribution bars) is the lesser of 5(135) and 450 mm. 0020. Lap length 50d = 50 × 16mm = 800mm. f yk = 460 Mpa. Modify ACI 318 Sections 17. The need for a com-posite slab roof may also affect architectural and MEP details, hence the need for a decision early in the design process. 1. Bar schedule for Slab; Table 3 : Bar schedule for SlabArea of single bar = (3. Beams = Self Weight per running meter. Type and spacing of the control and construction joints. Maximum size of bars in slabs As per clause 26. 0018 times the slab's gross area, but the maximum spacing of the bars differs. C slabs. Waist slab Bar Bending Schedule. And depth of check is determined as per IS 456 standards. 5, the lateral spacing of the. Slab steel bar not less than 10mm dia. The maximum spacing between stirrups is smallest of the following provided that (V s <0. 14. 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. 15%of gross cross-sectional area if plain bars are used and 0. This smaller amount of reinforcement0. 8 ACI 318 , Section 17. 6. (c) Distribution. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. t + d Lsy. C. Bars of distribution equal 16. Full bond Full bond h/2 Filler Figure 15:3: Contraction joint 15. 8. The number of the bars is seventh factor taken in basic rules in column design. , if the upper bar of 16mm dia. 1 of code IS 456:2000. 3. To distribute the superimposed load to the main bar. Consider the ACI 318-14 code according to which the Ø is the strength reduction factor as specified in table 21. Code of practice for plain and reinforced concrete ( third revision ) Specification for high strength deformed steel bars and wires for concrete reinforcement ( t&d revision ) Criteria for earthquake design of structures (fourth revision ). total angular change of tendon profile from tendon jacking end to point under considerations, radians. equal to ( C < 2. 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. 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. 5 m). Also useful for attaching stirrup bar effectively. 3. 60. Main Bar = 12 mm, Spacing – 150 mm c/c, Alternate bent up. For instance, the ACI 318-19 specifies minimum slab thickness that satisfies deflection. Spacing of bars = 180 mm c/c < 300 mm and 3d ok Distribution steel =. Calculation of the loads. 1 or the bottom bars required by 8. Calculation of number of distribution bars. 1. 24. . Type and spacing of the control and construction joints. 6 𝑀𝑃𝑎. 13. c 0. 2: Alternate method for showing two-way slab reinforcement reinforcing bars should be clearly scheduled on the drawings. 3. To calculate: Spacing of replaced 12mm. bar. 26. There is two spacing between 3 reinforcement and 50 mm length both side of 1st and 3rd reinforcement used in footing. Tayabji (1986) identified the following categories of dowelmillimetres and N represents the identification number of the bar/bars given consecutively. R4405. 2. 5] = 120 mm c/c. 6 bars shall not be used for S1 and S2 bars due to interference with strands and other reinforcement. For rectangular footings bars in long direction should be uniformly spaced. 0. TRANS REINF - Reinforcement required along the transverse direction ( along local Y axis of the plates ). In two way slab, distribution bars are provided in both sides of slab. 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. 3. Cutting length= 9000 – 2 x 50 =8900 mm =8. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. Design Guide on the ACI 318 Building Code Requirements for Structural Concrete. (i) The pitch of the main tensile bars in R. Step Assume load capacity of dowel bar is 40 percent wheel load, find the load capacity factor f as. Difference Between Main Bars. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm. 21Two-Way Slabs 6 b- Distribution of the total factored static moment to negative and positive moments: I. 89 M. 1. 4. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. from deviations in bar spacing and bar size are shown in figure 5. Step 4 – Extra Top Bar. 230/0. , Chapter 12 c c = clear cover of reinforcement, in. 12. 2. What is the maximum spacing of bars in slab? 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. The Main. 150m = 150 mm. The design of a one-way slab can be done by using the Indian standard code. Maximum Reinforcement Ratio:In this video, you will learn the Spacing between the Main and Distribution steel bar. 11 bars and smaller, continuing reinforcement provides double the area required for flexure at. The maximum diameter of the reinforcement bars in RCC slab is should not greater than (1/8) of slab thickness as per IS code provision standards. 3. Dia of Bar to be provided 'd' = 16 mm (round bar) Area of cross-section of 1 bar = 0. Number of bar =radius /spacing. From clause 26. Since diameter of bar = 10 mm. 2 or 8. Main Bars and Distribution Bars in Slab and Their Function. 4H to 0. According to Clauses 8. Minimum spacing for distribution bars is, (1) 5d = 5 X 76 = 380 mm (2) 450 mm . (Rebar Calculation Formula) No. Concrete Reinforcement January 2008 15-3. Calculation of no of bars required in slab reinforcement Number of bars = length of lab/spacing +1. 5. 5. The slab has to carry a live load of 4 KN per meter square. 53 Compute moments At support: ( - ) M1 = 3. Step Find the length of the dowel bar embedded in slab by equating Eq. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. slab to provide shear resistance. Special surface finishes, including coatings. 2 mm. 2, can form no closer to the facesee table 3 for spacing. member has shallow depth of less than 150 mm (ex. 12, apply only to one-way slabs (all code sections cited hereinafter are from ACI 318-08): “7. 0020. The slab is not. The maximum spacing of reinforcement at critical design sections for positive and negative moments in both the middle and column strips shall not exceed two times the slab thickness (ACI Code Section 13. design wheel load 4000 kg. For. 0104 Ai. rainfall intensity in inches per hour for the building location specified in the plumbing code. Where a slab on ground is cast monolithically with the footing, one No. 15% of the gross cross-sectional area if. 7. Concrete cover to main reinforcing bars shall be provided per AASHTO Table 5. 2. AS3600-2009 P P Lsy. According to ACI Code 7. 2 or 8. 090 square inches per foot of slab width, required each way. Hence, in the above given example spacing for 16 mm dia bar has been calculated, thus. The diameter of the main bar is 12 mm in diameter with 100 mm c/c spacing and the diameter of the distribution bar is 8 mm with 130mm c/c spacing. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. 8 ACI 318 , Section 17. 096 square inches per foot (or #4 bars at 18 inches center to center to meet ACI criteria, As = 0. What should be the diameter of chair bars used in construction? Typically, chair bars are made of reinforcement with a diameter of 12 mm and above. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. 4. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. Important Point: As per IS 456:2000, the limit on minimum reinforcement along either direction has been specified. 12. 3 Slabs-on-ground with turned-down footings. 1. Ex. The “D” bars shown in the tables conform to Article 9. 2. As = 0. 3) For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. 26. 6H to 0. 1. In. 2. Clear cover (top & bottom) = 50 mm. Distribution Bar = width of the foundation – 2 CC ÷ Spacing +1. Minimum Reinforcement Ratio in Slabs. Step 2 – Calculation of Cutting Length. C. of Main bars = (3000)/150 + 1. 7. Basic considerations. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any. , 450 mm. Provide a thickness of D=120 mm. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. 3—Corner restraint in slabsColumn = Self Weight x Number of floors. 2. 2. Concrete cover = 25 mm. is for dowel diameters to be one-eighth of slab thickness, dowel spacing to be 12 in. For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. C. tangential spacing of legs of links, st max. EXAMPLE PROBLEM 1. Provided spacings, therefore, satisfy the requirements. Plain bars———–10 mm Ø min dia Deformed bars—–8 mm Ø min dia; For Distribution bars: Plain bars———–6 mm Ø min dia Deformed bars—–6 mm Ø min dia; 4. 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. Lap length diameter: When we extend the top bar of the column from the bottom bar, having an unequal diameter, then the lap length is calculated for the smaller dia. 5—Application of the simplified method 3. 8. e. 5 m as per IRC. c. The slab is not. B. t + D Chair bar per square meter. Step 2: Calculation of cutting length ( for main bars and distribution bars) Cutting length of main bar = Clear span of slab + (2 × Development Length) ( 2 × D e v e l o p m e n t L e n g t h) + Inclined Length - Bend Length. The diameter of the chair bar should not be less than 12 mm. 6. 3. 12% of the overall sectional area. Distribution bars are placed on the top of the. The slab edge insulation for heated slabs shall not be required to extend below the slab. 5 m as per IRC. 4. Cover block use 15 to 20mm. 1. 3. 1 of IS 456), the maximum spacing is the. bar due to its non-availability. A minimum of three bars evenly placed in the lap length is required. C. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 7. 25 8 #5 12 6 6 2 4. 2. Practical considerations of one-way slab • Spacing shall be between 150-200 mm (main bars) • Spacing shall be between 150-300 mm (distribution bars) • Max. 3) For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. According to ACI Code 7. 2 m), regardless of steel grade. joint spacing greater than 50 ft (15. 1123 mm.