If it is desired to replace 10 mm bars by 12 mm bars, then the spacing of 12 mm bars should be. of Main bars = (3000)/150 + 1. Minimum Reinforcement Ratio in Slabs. Spacing = 150mm c/c as per given details = (6000/150) + 1. As per IS 456: 2000, clause 26. Only 2. 5. Minimum Reinforcement Ratio in Uniform Footing. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. 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. correct. k = (5. 0014: (a) Slabs where Grade 40 or 50 deformed bars are used: 0. 5. Current recommended. Main Reinforcement bars are placed in shorter direction and Distribution bars placed in longer span direction. However, the same for secondary/distribution bars for temperature, shrinkage etc. 9. NOTE 3 - In co1 3. Spacing of Main Reinforcement: The maximum spacing of bars shall not exceed. 3 – When spacing of tendons exceeds 54 in. 3. 5, the lateral spacing of the. Weight of Distribution Bar for Waist Slab. In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. Placed at a shorter span. b. 0146. 1-1 and its accompanying notes, except as modified herein. 7. 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. Length of waist slab= L. This type of reinforcement is convenient for modeling beam reinforcement. Now assume diameter of bars and calculate spacing between bars. bars in two-way slabs. 347. 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. The diameter of the chair bar = d =12mm. 2 Effective Length ofCompression Members 25. Thickness of Slab = 0. (b) One-way joist systems in accordance with 9. Roof drainage system (Adapted from the International Code Council). This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. 4 times effective depthThe precast concrete product, which is used to provide the necessary covers or spacing for the reinforcement bars from the formwork, in all the RCC structures like slab, column, beam, footing, etc. 6. As = 0. Unit weight of concrete = 25 kN/m 3. 1 In slabs, beams and girders, splices in reinforcement at points of maximum stress shall be avoided wherever possible. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. 4. Height of block wall = 2. Distribution bars are placed on the top of the. Sub-Grade and. In. thick slab will increase the potential for random or out-of. 10. 1 or the bottom bars required by 8. 5] = 120 mm c/c. 42d. If redistribution is carried in design, the allowable max spacing needs to be reduced or relaxed as per table 15 of IS456. each way at center of slab construction joint for same shall not be more than 3000mm apart. per 18-in. reinforcing parallel to load per inch of slab width perpendicular to load / slab thickness) (steel yield stress)) f. Calculation of effective depth. How to Design Concrete Structures to Eurocode 2 - Chapter 2: Getting started. 4, Chapter 10 ct = distance from the interior face of the column to the slab edge measured parallel to c1. Minimum requirement in slab : As per clause 26. = 175 mm Last perimeter, from column face, min. 26. Distribution bars typically have lesser dimension bars compared to main bars. 2. Five times the effective depth of slab, and; 45 cm. Joist system relative dimensions, slab thickness, rib width and spacing between ribs are specified in ACI 318-05, Section 8. Spacing of Main Reinforcement: The maximum spacing of bars shall not exceed. 2. 2. , Chapter 12 c c = clear cover of reinforcement, in. 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. Distribution Reinforcement) Class B (Not Top Bars) J, NThe span requirement for the slabs is given by ACI Code 8. Main Steel – 3d or 300 mm whichever is smaller. 6. 9 m = 3. The slab requires 51 main bars. 3. So maximum diameter of reinforcement bar used in 5 inch (125mm) thick. 6H, and 0. , i. Joints are provided in concrete pavements to control. e. Fig. 4 MoVEMEntS And rotAtIonS: 4. 1—Minimum flexural reinforcement in nonprestressed slabs 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. These were developed for slabs of “ordinary” proportions supporting gravity loads, and they may not be sufficient to intercept potential punching shear cracks in thick transfer slabs, podium slabs, and mat foundations. This portion is coming at the top of the bottom main bar. Unit weight for feet per metre = (D2/ 533) × L kg/ft. 3. Also useful for attaching stirrup bar effectively. i,e. 11. 8 ACI 318 , Section 17. 3 of IS 456). 53 Compute moments At support: ( - ) M1 = 3. 2 mm. 6. As = 0. 4 Slabs Spanning in Two Directions at RightAngles 24. Longitudinal reinforcement should not be less than 0. You just enter your information in the yellow colour box for the design of two way slab excel sheet as per is 456 such as. A minimum of three bars evenly placed in the lap length is required. Clear cover (top & bottom) = 50 mm. The steel reinforcement in SS/NS wall and slab shall be welded steel fabric mesh for steel bar diameter of up to 16mm and hot rolled steel bars. Distribution steel: 0. And, in compression zone, same as in (a) above. Total Length of Distribution Bars = 19. 7. anchorage to longitudinal bars and confinement of core concrete in resisting shear2. According to it, if a slab rests on its support freely, the span length may be taken as equal to the clear span plus the depth of the slab but need not exceed the distance between the centers of supports. 785 x 16^2 = 200. According to it, if a slab rests on its support freely, the span length may be taken as equal to the clear span plus the depth of the slab but need not exceed the distance between the centers of supports. 225m. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. Slabs - - - maximum spacing is 3*deff or 300mm whichever less side ) of the deformed bar ( see Note ) NOTE - In accordance with IS : 1139-1966. This smaller amount of reinforcement0. Conclusion. Thickness of the slab=l x /32= 98. 3. 3 times effective depth c. design wheel load 4000 kg. Provide main reinforcement of 10 mm diameter bars at 120 mm c/c. 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. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. This is plotted against the overall fire rating of the structure that is being designed. Sub-Grade and. Also useful for attaching stirrup bar effectively. 20 square inch (129 mm 2) in cross-sectional area shall be provided: 1. iv) Detrmine Sapcing of bars at critical section based on designed value of Ast by selecting appropriate bar dia. 2 to read as follows:Top & bottom distribution bar dia. If the reinforcing bars do not extend beyond the critical section. 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. 1. 1 given below by the ACI 318-14 code. 3 Slabs Monolithic with Supports 24. Distribution Bar. Note that required A s must be furnished in each direction. 40 cm;. 12% of the gross cross-sectional area if HYSD bars (Fe 415) are used. Where a slab on ground is cast monolithically with the footing, one No. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. Step Find the length of the dowel bar embedded in slab by equating Eq. spacing of reinforcing bars (cls. 12 x 100cm x D cm=0. 1 - 10mm Ø vert. it's a tool to maintain the spacing between two separate layers of slabs, footing etc. 1 Answer. Section 8. 8. as per ACI 318. 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. Figure: Contraction joint;. 890m. e min = (L/500) + (D/30) ≥ 20 mm. Instead, to comply with ACI minimum reinforcing ratio and bar spacing requirements, slabs from 4 to 7 inches thick should have at least #4 bars at 12 inches on centers; closer spacing or larger bar sizes are needed for thicker slabs. 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. Dia of Distribution Bar=16mm. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. 3. >EAST side. 12% of cross-sectional area as distribution rebars as per. Given the radius of relative stiffness of 90 cm. 5 bar or two No. as indicated in the table. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. 7. joint spacing greater than 50 ft (15. 4 bars in the middle third of the footing depth. 4 bars in the middle third of the footing depth. 3 only and there is no need to perform specific checks on the bar spacings to control cracking. bar. As per IS 456:2000, in rcc slab, maximum diameter of main bar and distribution bar should not exceed 1/8th thickness of slab. e. 4. 10m , Depth of Slab = 0. 1. 2) For main bars, maximum spacing is restricted to 3 times effective depth or 300. 6H, and 0. Particular care isIRC SP 066 : 2016 is a standard specification and code of practice for the design of steel pedestrian and cycle bridges in India. 8. 12% of the gross cross-sectional area if HYSD bars (Fe 415) are used. slabs, walls, and joists - #14 and #18 bars - ½ inch; Slabs, walls, and joists - #11 bars and smaller - ¾ inch ; Beams and columns. 8. A = roof area in square feet drained by the drainage system. For Min Steel: 3d ——— Where. 3. k < 0. What should be maximum spacing of main and distribution bars in slab?We would like to show you a description here but the site won’t allow us. One Way Slab Reinforcement Detail. 7. is for dowel diameters to be one-eighth of slab thickness, dowel spacing to be 12 in. 7. 21Two-Way Slabs 6 b- Distribution of the total factored static moment to negative and positive moments: I. áTie the bars at the top and the bottom irrespectively. Design the slab using the data given below; Purpose of building – Residential. Wall Load Per Running Meter. There are 51 nos of main bars are required for the slab. The code itself suggests that the diameters can be #3, #4 and #5. Spacing: ACI Code 7. 5. The span requirement for the slabs is given by ACI Code 8. however with a maximum spacing of 4. Ensure that the return bars at the edge of the slab are a minimum of ¼ (15%) of the length of the adjoining span. C. 5 m. If we increase the spacing beyond 200mm the column section buckling effect will occur. 6—Factors affecting the construction load distribution 3. Some discussion to decide about max spacing: AS per IS 456: Maximum spacing for bars in beams is 180mm for Fe415 grade and 150mm for Fe 500 grade reinf. R4405. The distribution bars number 17 in total. 2. 12. 4. where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. 11. of distribution bars = Ly/Spacing + 1 = 2000/150 +1 = 14. The below specified 7 steps are generally used to design the two way slab. The Distribution bars will be 8 mm in diameter @125mm c/c spacing. 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. 5. BS EN 1992–1–1 section 6. 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. So, provide spacing of distribution bar equal to. = 27. =Eq. 11*12 in c/c Step 6 : Temperature and Shrinkage ReinforcementWeight of distribution of 8 mm dia steel bar = 33. Spacing Requirements. For ASTM A 497 deformed welded wire fabric Values in the subgrade drag equation Data of Calculate Steel in Rcc Slab-. The spacing of the lateral ties is 100mm to 200mm for safe structure design. The spacing of the chair bars depends on several factors which are listed below: – Diameter of the bar used in making a chair. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. Length of the Slab = 5 m = 5000 mm. 133 square inches per foot). 2. The punching shear capacity is obtained via the ACI code equations, seen below. 6m . 25 kN/m 2. 2. 3. EXAMPLE: Suppose we have a one-way slab, which has a length of 5 m or a width of 2 m (clear span). (15) Step Spacing of the dowel bars. 667’ x 40. Design Guide on the ACI 318 Building Code Requirements for Structural Concrete. and 𝑓𝑦 = 276 𝑀𝑃𝑎 for main and temperature bars. 4. Development length = 40d. As always, local service records are the best guide for determining trans verse joint. 1 Overview 4-1 4. 1 Spread Box BeamsA. 7. Given data: Distribution bar dia. 5% steel (continually reinforced) as described in Section 8. This is also. 2 to read as follows:In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. 090 square inches per foot of slab width, required each way. 002 times the gross cross-sectional area of the footing. A cantilever slab 200 mm thick is 1. 6. 3. Design procedure. 4: Two-way slabs having multiple spans; The purpose of the code is to design the total amount of reinforcement steel rebar into principal directions in the slab system. 1 of IS 456), the maximum spacing is the. 16. 975 KN)/ (39. Spacing s of longitudinal bars in precast walls shall not exceed the lesser of (a) and (b): (a) 5h. 9, page 341. Distribution bars are provided in the longer span direction. According to ACI Code 7. What is the minimum number of main steel bars provided in RCC?the transverse wire or bar and the transverse joint, will not exceed 3 inches or one-half of the wire or bar spacing in the fabric or mat. To firmly hold the main bars in their. 4—Construction load distribution 3. 2). , addi-tional bonded shrinkage and temperature reinforcement conforming to 7. Step 4 – Extra Top Bar. Provided to resist the shear stress and cracks. 2. These were developed for slabs of “ordinary” proportions supporting gravity loads, and they may not be sufficient to intercept potential punching shear cracks in thick transfer slabs, podium slabs, and mat foundations. Check spacing of bars. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. For basic building the 4 number of bars is sufficient as per code. In Flat plate slab the, distribution bars are arranged in one direction at Top of main bar (in longer span). Step 1. three times the effective depth of solid slab or; 300 mm; whichever is smaller. 11. Distribution bars of diameter 12 mm and center to center spacing 150 mmm. A diagonal crack that might result in shear failure, as suggested in Fig. 3 Design of the slab (per meter strip) Bending moment on the slab is maximum at the face of the column (in this case at the face of the upstand beams) (clause 3. 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. 10 the minimum bar spacing for bundled bars shall be calculated based on the derived diameter instead of calculating from individual. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. 33(fc') 0. 230/0. 300mm. 2 m), regardless of steel grade. 14 x 5 x 5 = 78. 6. 19 or greater, the minimum concrete cover is 5 cm. 6 = 17. STEP. 7. = 2sqm/1sqm = 2nos. 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. Check resistance to moment transfer from column to slab . Load Distribution. Total length = 3. This spacing should be reduced by a factor of 0. S. 2. 1 or the bottom bars required by 8. ,). Distribution bars are provided perpendicularly with the top of the main bar. Unbonded Cross Sections" for discussion. 2—Minimum flexural reinforcement in prestressed slabs 8. Provide a thickness of D=120 mm. 3. The distribution bars should be (2000- 2 x 25) /125 + 1. The size and number of reinforcing bars must be chosen to (1) provide an area of reinforcement equal to or greater than the amount that is required, and (2) satisfy the minimum and maximum spacing requirements in ACI. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 12: Reinforcement detail in continuous slab 3. 4—Construction load distribution 3. 00mm Bottom Footing Clear Cover (F, CL). 5 m). The “D” bars shown in the tables conform to Article 9. The Indian Standard (IS) code for the preparation of steel bar bending schedules is IS 2502:1959. 1. BBS of One Way Slab. Dia of Main Bar=16mm. The manual design process included the reinforcement calculation for the main. 42D) – (1d x 4) – (2d x 2 (From BBS shape codes) d = diameter of the bar. , 300 mm. Distribution Bar = 10 mm, Spacing – 150 mm c/c, Alternate bent up. , see 10. c. 2 Minimum Slab Thickness 4-1 4. Continuously at structurally connected roof and floor levels and at the top of walls. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. What are the distribution bars in a slab? The reinforcement bars that are placed above the main bar in a one-way slab, to distribute the superimposed load to the main bar are called distribution bars. 34 kg ——– (1) Section 1 Total = 33. *A4 size is 210 x 297 mm. 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. 6% of the gross wall area for Grade 60 or Grade 40 bars, respectively. No. Factor affecting spacing of chair bars. 4 must be met, and max. of main bars = Lx/Spacing + 1 = 5000/150 = 34. ,). 26. 12. Use bar support in order to maintain the space between bars at the top and bottom and then the distance will be correct. 3-Main bar Bottom Area Given data. 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. Concrete cover = 25 mm. iv) Detrmine Sapcing of bars at critical section based on designed value of Ast by selecting appropriate bar dia. 1. L 1 = (2 x spacing of distribution bar) + (2 x the clear cover). 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. bar per corner 10mm Ø vert. 15=7no’s. The minimum spacing between the two bars can be about 50–75 mm. 62 m, 9. 36 Live load Canopy = 1. (14) Step Find the load transfer capacities , , and of single dowel bar with the. It is mainly to prevent upward bending moment near the joint. Weight of Main Bar = (102/163) x 126. Dia of Bar to be provided 'd' = 16 mm (round bar) Area of cross-section of 1 bar = 0. 1.