Breadth of Footing = Y = 1. 0014: (a) Slabs where Grade 40 or 50 deformed bars are used: 0. 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. 3(1) of IS 456, is the lesser of 3(135) and 300 mm. 25 x 87. 7. For longitudinal bars in columns of size more than 200 mm. This spacing should be reduced by a factor of 0. 4—Construction load distribution 3. Distribution bars are provided perpendicularly with the top of the main bar. The length of a distribution bar in west side is the same as the east side. Distribution Bar. If it is desired to replace 10 mm bars by 12 mm bars, then the spacing of 12 mm bars should be. 3 m) is either 0. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. Height of block wall = 2. No. 26. LL = 6. 2. 6m . Note * rationalise centre of bars in column strips T2 and B2 to 175 mm centres to suit punching shear links. Lesser dimension bars are used. 5 m as per IRC. deck slab and diaphragms, spliced girder system, precast pre-tensioned open or closed. C. 2. bars at 400 mm o. Concrete cover = 25 mm. Distribution Bars are used to hold the slabs on either way and to resist the cracks. Step 1. 12. 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. 3. The equivalent of closer-spaced, typical slab bars can be achievedf DESIGN of ONE-WAY SLAB based on NSCP 2015 and ACI 318-14. 4 bars in the middle third of the footing depth. Provided spacings, therefore, satisfy the requirements. exposed to earth or weather. Eurocode 2 section 9. , and ℓw/3. a = axial spacing of the bar for calculating the lap length (ci. . Head of Chair: Length of head = (2 * spacing of distribution bar) + (2 * 50) = (2 * 150) + (2 * 50) = 400mm. Concrete cover = 25 mm. Area of reinforcement per metre width of spacing. For footings that exceed 8 inches (203 mm) in thickness, a minimum of one bar shall be provided at the top and bottom of the footing. C slabs. Ensure a minimum number of bars in a square column is 4 and in a circular column, 6. 230m. Weight of the bar as per their length and diameter by following the Formula: –. Where a slab on ground is cast monolithically with the footing, one No. Figure 3. Check for Cracking. 3. Main Bar = 12 mm, Spacing – 150 mm c/c, Alternate bent up. 3. 5. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. For instance, the ACI 318-19 specifies minimum slab thickness that satisfies deflection. 1 for minimum thickness of non-prestressed two-way slabs without interior beams is revised to include Grade 550. For Edge Spans : Static Mom. As per IS 456: 2000, clause 26. Maximum spacing of bars for slabs • Main bars: 3h ≤ 400mm (in areas of concentrated loads 2h ≤ 250mm) • Secondary bars: 3. 9. Total length of Foundation Distribution bar =No’s of bar x cutting length. 26. 1% of the slab cross-sectional area) through sawcut contraction joints in combination with the recommended joint 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. Concrete cover to main reinforcing bars shall be provided per AASHTO Table 5. 5. joint spacing greater than 50 ft (15. IN Downloaded from Ktunotes. The spacing between longitudinal reinforcement of the column should be the greatest of the following: 4 cm; 1. 4. 133 square inches per foot). Maximum Reinforcement Ratio:In this video, you will learn the Spacing between the Main and Distribution steel bar. Step 1- Calculation of Numbers of Bars. Step 1. Check spacing of bars. 1. However, in some cases, 10mm dia bars are taken for the floor slab, when there is no extra external load other than reinforcement mesh load. slab, shall not. , see 10. (Rebar Calculation Formula) No. 12: Reinforcement detail in continuous slab 3. 15=7no’s. 1 of IS 456), the maximum spacing is the lesser of 3d and 300 mm i. The maximum spacing between stirrups is smallest of the following provided that (V s <0. The maximum spacing of minimum steel (distribution bars) is the lesser of 5(135) and 450 mm. Fig. spacing in plates and two-way slabs with concrete covers. 12% of high yield strength deformed bars. FAQ . That is 11′. Spacing = 150mm c/c as per given details = (2950/150) + 1 = 20. 15%of gross cross-sectional area if plain bars are used and 0. If a closer spacing of bars is required at the columns, as per Section 13. No of main. For basic building the 4 number of bars is sufficient as per code. Total Length of Distribution Bars = 786. 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. 3%. 3 introduces a new requirement for bar 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Reinforcement chairs should be made with a minimum of 12 mm bar. If the maximum diameter for. Slab steel grid not less than Fe500. 26. 7. 2. 9. SECTION 5: CONCRETE STRUCTURES 5-5. Provided to resist the bending stress. the constant value of 50. 6. 15%of gross cross-sectional area if plain bars are used and 0. This is also. 2). L is the required length of the Steel bar of Diameter D. Design ProcedureAllowable clear spacing of bars = 3d = 3(170) = 510 mm Actual clear spacing = 300 – 10 = 290 mm < 3d → ok Figure 3. b) In partially prestressed superstructure: In tension zone it shall not be less than that calculated as per Sections 12 and/or 16 (whichever is higher) of IRC:112. 60. 66 < 2. Length of waist slab= L. Adequacy of curing. What is the maximum spacing of a distribution reinforcement to be used in a one way slab as per IS 456? b. how to calculate the number of rebar in an exceedingly circular block. You can design the two way slab using our android application. Most of these formulas are based on the analysis of results of tested beams or oneway slabs. 1000 1500 2000. 2 times effective depth b. 2). 6. 5. (c) Distribution. Given Data: Height of footing = 600 mm. 8 say 16 nos. ) = 200. 3. 5m . 2 Maximum Distance between Bars in Tension. 3d or 300 mm whichever is smaller for main steel. 6. 3 Direct supply of steel reinforcing bars to site by QA Manufacturer 27 Section 5 Purchasers testing 28 5. Dia of Main Bar=16mm. 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. 3. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. 13. 10m , Depth of Slab = 0. Spacing s of longitudinal bars in precast walls shall not exceed the lesser of (a) and (b): (a) 5h. What is the maximum spacing of bars in a flat slab? The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 15m. Important Points. 5 M from the edge of wall and at both ends 6 mm plain M. 5 Spacing limits and concrete cover for reinforcement shall be shown on the design drawings. Total Length of Distribution Bars = 19. Effective depth=d provided =120-20-4= 96 mm. (2× Spacing of distribution bar) + (2×25) = (2 x 150) + ( 2 x 25) = 350 mm . 24. 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. Spacing of bar = area of a bar * width of strip / area of reinforcement required = 78. (a) for a distance equal to the larger lateral dimension of the column above and below a beam or slab, andvii) Any other function assigned to the expansion joint as per the specific requirements of the structural systems. For example, for 12mm. Minimum Bar SpacingAs per AASHTO LRFD, section 5. 7. 1. of bars= (Slab length (L)/spacing)+1 Equation 1. 2. 2: Alternate method for showing two-way slab reinforcement reinforcing bars should be clearly scheduled on the drawings. Is 1200 Important Point Part-1; IS Code for Civil Engineer [Q&a]. For 8 mm diameter bar 7 inches to 9 inches center to center c/c. The Distribution bars will be 8 mm in diameter @125mm c/c spacing. where. 1 (3) Solid slabs: the maximum spacing of flexural reinforcement bars s max,slabsThere are 2 types of bars in one 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;. rahuledu said: as per IS 456:2000, chair shall be fixed 1 no in 1 Sq. 2. No. Provide main reinforcement of 10 mm diameter bars at 120 mm c/c. What Is The Maximum Bar Spacing In Reinforced Beams According To IS 456? Normally this. For longitudinal reinforcement in columns of size 200 mm and less, with 12 mm diameter bars as longitudinal steel. So, provide spacing of. bars should be arranged as distribution bars and are provided at 30 cm centres at the top of the. If we increase the spacing beyond 200mm the column section buckling effect will occur. × c/c distance between the top distribution bar) + (extra length on either side of the top distribution bar)]Calculate the nos’ of facet rebar. Step 4 – Extra Top Bar. 14. For concrete cast against and permanently. 4. 5 inches, and the transverse bars must be fully developed in grouted masonry at the point where they cross the lapped reinforcement. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. For the cranked bars near the supports at the top of the slab distribution bars of same size and same spacing are provided below the top bars. The reinforcing bars must extend into the slab beyond the critical section for a required length. e. Bar crank. 2and3 C. Now assume diameter of bars and calculate spacing between bars. Provided at the bottom of the slab. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. No. 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. A s,min,reqd ≥ b*h*0. 7. The distribution bars’ primary function is evenly distributing the load across the slab. 4 Deck Overhangs for guidance on deck slab bars. ACI 7. 2. 1. 10 cm; 12 cm; 14. 3. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. 24 SOLID SLABS 24. 2 (7) Beams: the maximum longitudinal spacing of bent-up bars s b,max; 9. Waist slab Bar Bending Schedule. To firmly hold the main bars in their. 2. 225m. 1. Opposite length of bar = 2950. Calculate cutting length: calculate the required number of bars for both directions. 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. f. 2. 5 Admixtures 5. e. 2. 1 Spread Box BeamsA. and the clear spacing between the bottom bars a = 60 mm. bar due to its non-availability. Top and bottom clear cover of slab is 20 mm. Distribution Bar = 1800 -2 (75) ÷ 150 +1. 3. Here, ∅ is the bar diameter. Also useful for attaching stirrup bar effectively. 2 mm. As per clause 26. The flow rate, Q, in gallons per minute, can be computed as follows: Q (gpm) = 0. 1. 6. Where a slab on ground is cast monolithically with the footing, one No. ”Distribution bars are typically used in conjunction with main bars, and they are often spaced at regular intervals along the length of the main bar. 4H to 0. BS EN 1992-1-1 Annex 1 1. length of. Leg of Chair= (2 * spacing of bottom main bar) + 50Plain 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. The spacing of the lateral ties is 100mm to 200mm for safe structure design. 715m long, and it is supporting a blockwork load at 1. 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. R4405. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs. 4 Water 5. 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. Figure 3:. Step 1. cm. 17 The design of one-way slab is simple and can be carried out easily. 4. 2. Step 2: Calculate cutting length of main bars and distribution bars. 3. i = 100-yr. Rebar steel will be calculated for the bending moments “Mx” and “My. The Main bars will be 12 mm in diameter with 100 mm c/c spacing. 4. . 3. 3. 08 times the gross area of the column. (c) Deep beams in accordance with 9. 26. Number of Required Bars Formula = (Length of slab / spacing) + 1. , B. 3. Length of the Slab = 5 m = 5000 mm. ACI 318-19, Table 8. 75H for surcharged wall. 6 𝑀𝑃𝑎. 4. Spacing of 10mm bar = S1 =150 c/c. 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. 14 x r x r) = 3. For footings that exceed 8 inches (203 mm). 6. t + D Chair bar per square meter. 305. 2, 17. The term "standard hook" as used in this Code shall mean one of the following: (a) 180o. 9 Factored loads Factored dead load = 3. 1. 300 Area of bars Φ12, a=π62 = 113. 15% of the gross cross-sectional area if mild steel bars are used. On the bigger side, distribution bars are supplied, however, they will not assist in bearing any weight. i,e. 5. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. 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. Side clear cover of slab 25 mm; Thickness of slab is. ' = 1536 sq mm. As per IS 456:2000, in rcc slab, maximum diameter of main bar and distribution bar should not exceed 1/8th thickness of slab. 6. with 12mm. 2 Minimum Slab Thickness 4-1 4. 230/0. The spacing of the chair bars depends on several factors which are listed below: – Diameter of the bar used in making a chair. 5. 3. (table 15). In the. 3 times effective depth c. design wheel load 4000 kg. Max. b) Slab depth does not exceed 200 mm when the steel grade is 460. M. Wood structural panels with a minimum thickness of 7 / 16 inch (11. 2. Exceptions: 1. 5, the lateral spacing of the. If redistribution is carried in design, the allowable max spacing needs to be reduced or relaxed as per table 15 of IS456. Size of the bar is higher than the distribution bar. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 4 MoVEMEntS And rotAtIonS: 4. 3. Diameter of a chair bar should not be less than 12mm. Refer to Section 5. 12. Concrete Reinforcement January 2008 15-3. and : 1786-19667, the nominal size of the deformed bar is equivalent to the diameter or side of a plain bar having the same weight per metre run as the deformed bar. The complete calculation for one way slab is explained in the below steps. Minimum S&T reinforcement quantities required by ACI 350-01 and11. Dia of Bar to be provided 'd' = 16 mm (round bar) Area of cross-section of 1 bar = 0. 3. 9 for flat slabs with drops. Since diameter of bar = 10 mm. , nonskewed) bridges only. for interior walls. No. Select the correct answer using the codes given below: A. C. C. Suppose we have a one way slab,which having a length 5 m or width 2 m (clear span). 5. 5d or 450 mm whichever is smaller for distribution steel. Main Steel – 3d or 300 mm whichever is smaller; Distribution Reinforcement for Concrete Slab Design: The area of distribution reinforcement shall not be less than 0. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. The Department offers B. Height of block wall = 2. 26. 2. 3(d) and 17. 1 for minimum thickness of non-prestressed two-way slabs without interior beams is revised to include Grade 550. 8 ACI 318 , Section 17. The distribution bars’ primary function is evenly distributing the load across the slab. Calculation of effective depth.