3. 3. 26. Diameter of Distribution Reinforcement Bars = d d =12mm. 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. continuous slab – code coefficients-. Provided to resist the shear stress and cracks. Design of the footing cantilever slab portion (per meter strip) Note that the bending moment in the slab is maximum. slab, shall not. BBS of One Way Slab. VARIATION AMONG BETWEEN MAIN BARS AND DISTRIBUTION BARS: 1. 5 in Y-axis Distribution area 3. Adopt a clear cover of 20 mm and 8 mm diameter bars. 1. Given data: Distribution bar dia. iv) Detrmine Sapcing of bars at critical section based on designed value of Ast by selecting appropriate bar dia. slab known as a joist system can be constructed without any shear reinforcement in the joist ribs. Main Steel – 3d or 300 mm whichever is smaller. Flexural tension reinforcement shall not be terminated in a tension zone unless (a), (b), or (c) is satisfied: (a) Vu ≤ (2/3)ϕVn at the cutoff point. 4 bars in the middle third of the footing depth. 3(1) of IS 456, is the lesser of 3(135) and 300 mm. 5 times effective depth d. 3. (table 15). 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. ratio of flexural stiffuess. Head ( E ): The length of the head = [(2nos. Provide a thickness of D=120 mm. , if the upper bar of 16mm dia. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. Collectors, Chords and ConnectionsIS Code. 3. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. 3. 9. bars at 400 mm o. Bars shall not be smaller than No. 2), The bar spacing shall not exceed 450 mm at any location (ACI Code Section 7. ? 1. Consider 28 Nos. Main Bar = 12 mm, Spacing – 150 mm c/c, Alternate bent up. For eg. The slab has to carry a live load of 4 KN per meter square. 2: Alternate method for showing two-way slab reinforcement reinforcing bars should be clearly scheduled on the drawings. This reinforcement is reported in terms of area required per unit width of slab. 3. The size and spacing of S1 and S2 bars shall be determined by design. 5—Application of the simplified method 3. 36 Live load Canopy = 1. 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. 18% for higher concrete grades. DESIGN OF SLAB: Design of typical Floor Slab: We have thickness of slab as 130 mm. The clear cover will be 25 mm(Top or Bottom) and the thickness of the slab is 150 mm. Here we have to calculate the number of main bar and distribution 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. The maximum diameter of the reinforcing bar in a slab should not exceed 1/8th of the total thickness of the slab. 6H, and 0. 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. Q) Design a reinforced concrete slab for a room of clear dimension 4-meter x 5 meters. A cantilever slab 200 mm thick is 1. The distribution bars are arranged to retain the mesh in exact location and keep the center to center c/c, bars spacing among main bars. 4. 11. 26. 12D Sq. 12. 8 ACI 318 , Section 17. 4 Spacing Between Longitudinal Bars. 3. per Section 6. 460/2=1. 3) or the distance of centre of gravity of the concentrated load from the nearer support (ci. 376Kgs For Floor slab -2 (One way slab) :-As per the above figure Floor slab -2 is a One way slab. 6. 1 of EC2, the recommended minimum spacing of reinforcing bars is 75 mm and 100 mm for laps. 2. in. The maximum clear spacing between parallel bars shall not be more than 1 N-6O. 230m. per 18-in. 2. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. 4. a) Slab depth does not exceed 250mm when the steel grade is 250. 2. 11. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. Type and spacing of the control and construction joints. Length of the Slab = 5 m = 5000 mm. Note * Spacing rationalised to suit punching shear links. Bar Spacing. Clause 6. The maximum spacing of main bars is limited to 3d or 300 mm (whichever is less). There are also new provisions for integrity reinforcement. GameStop Moderna Pfizer Johnson & Johnson AstraZeneca Walgreens Best Buy Novavax SpaceX Tesla. For instance, the ACI 318-19 specifies minimum slab thickness that satisfies deflection. (b) Horizontal reinforcement at least 0. Maximum size of bars in slabs As per clause 26. Top and bottom clear cover of slab is 20 mm. and 𝑓𝑦 = 276 𝑀𝑃𝑎 for main and temperature bars. Maximum spacing of tension bars (all slabs) In accordance with clause 7. slab, shall not. 89m. 12. normally lower dia rebar tends to more sagging while placing in top layer. 5 m as per IRC. L is the required length of the Steel bar of Diameter D. = 16mm, spacing @ 150 c/c. Breadth of Footing = Y = 1. 2 mm. 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. Step 4 – Extra Top Bar. 5d or 450 mm whichever is smaller for distribution steel. 2 to read as follows:Top & bottom distribution bar dia. 5. 2. IS 456: 2000 CONTENTS PAGE SECTION 1 GENERAL J SCOPE 2 REFERBNCES 3 TERMINOLOGY 4 SVMBOU SECTION 2 MATERIALS, WORKMANSHIP, INSPECTION ANDTESTING 5 MATERIALS 5. LL = 6. 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. For slabs 200 mm thick or greater, the bar size and spacing should be limited to control the crack width and reference should be made to Section 7. As always, local service records are the best guide for determining trans verse joint. 1000 1500 2000. Dowel bars are typically placed at the mid-depth of the slab and should be parallel to the pavement surface and parallel to the direction of travel. 9 Factored loads Factored dead load = 3. , addi-tional bonded shrinkage and temperature reinforcement conforming to 7. 3) or the breadth ofthe rectangular beam or slab or the breadth of the rib in case of flanged beam (ci. Sketch the detail of reinforcement. 54 * 1000 / 180 = 436. 15m. 2 of IS 456 :2000 , the reinforcing bars shall not exceed 1/8 of theThe minimum size and grade of rebar for slabs depends on a variety of factors, such as the thickness of the slab, the loads it supports, seismic requirements and other factors. ) = 200. 2. Weight of the bar as per their length and diameter by following the Formula: –. If a closer spacing of bars is required at the columns, as per Section 13. 7. k < 0. 6 in the following cases; In sections within a distance equal to 4 × thickness of wall above or below a beam or slab. 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. 1 Definitions 25. In. 15% gross c/s of slab – for MS bars; 0. For Min Steel: 3d ——— Where. Solving for the Number of Reinforcement Chair required per square meter: Since the chair reinforcements support only the top layer, then we will consider the weight of top mesh reinforcement as dead load. as per ACI 318. 8 ACI 318 , Section 17. 5] = 120 mm c/c. 1. C slabs. The main conclusions can be summarized as follows: • The proposed method gives a good estimate for crack. The maximum spacing between stirrups is smallest of the following provided that (V s <0. Design the slab using the data given below; Purpose of building – Residential. That is 11′. 2. spacing of reinforcing bars (cls. 53 Compute moments At support: ( - ) M1 = 3. critical section of the slab is just outside the outside edge of the beam supporting the slab. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any value. 8. 3. Special surface finishes, including coatings. 12% of the overall sectional area. 75H for surcharged wall Base slab thickness= H/10 to H/14 Toe projection= (1/ 3-1/4) Base width Behaviour or structural action and design All the three elements namely stem, toe and heel acts as cantilever slabs and hence the design In design of slab, as per IS-456, what should be minimum percent of distribution steel if Fe 415 reinforcement is used ? The minimum percentage of reinforcement is 0. Diameter of a chair bar should not be less than 12mm. is for dowel diameters to be one-eighth of slab thickness, dowel spacing to be 12 in. 3. reinforcing parallel to load per inch of slab width perpendicular to load / slab thickness) (steel yield stress)) f. Unit weight formula for kg per metre = (D2/163) × L kg/m. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. 5h ≤ 450mm (in areas of concentrated loads 3h ≤ 400mm) Where h is the thickness of. 7. exposed to earth or weather. 5% or 0. 6m. 5 times the diameter of the longitudinal barR4405. How to Design Concrete Structures to Eurocode 2 - Chapter 2: Getting started. 785 x 16^2 = 200. The diameter of the bars varies from 8mm to 14mm and should not exceed 1/8 th of the overall depth of. 2. 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. and the clear spacing between the bottom bars a = 60 mm. member has shallow depth of less than 200 mm (ex. Distribution of Main Bars. 6. This is also. For preparing the bar bending schedule according to the given data. C. Current recommended. , Structural. The distribution bars provide the following functions in slab construction: 1. ACI 360R, Section 6. 2 or 8. 960 x 16 =. . t + d Lsy. 75 m. Diameter of top and bottom distribution bars = 16 mm. 6. Provided to resist the shear stress and cracks. 2 d t kips in. =Eq. Select the correct answer using the codes given below: A. 4. Head of Chair: Length of head = (2 * spacing of distribution bar) + (2 * 50) = (2 * 150) + (2 * 50) = 400mm. 2 Spacing s of transverse bars in precast walls shall not exceed the. The Department offers B. 7. 2. 2) b = edge distane of bar for calculation of lap length (cl. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. For footings that exceed 8 inches (203 mm). = 2sqm/1sqm = 2nos. 2) For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. 40 mm or diameter of bar whichever is more 2. 25What is the maximum diameter of reinforcement/ bar used in slab as per IS 456: 2000:- there are two types of reinforcement/ bar provided in RCC slab, 1) main bar provided in tension zone of RCC slab and 2) distribution bar provided in compression zone. 1. length of. 5h ≤ 450mm (in areas of concentrated loads 3h ≤ 400mm) Where h is the. Dia of Bar to be provided 'd' = 16 mm (round bar) Area of cross-section of 1 bar = 0. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. and 𝑓𝑦 = 276 𝑀𝑃𝑎 for main and temperature bars. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. >EAST side. 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. Distribution bars are provided perpendicularly with the top of the main bar. 3. C. (ii) The pitch of the bars provided to act as distribution bars or bars provided to guard against temperature and shrinkage in an R. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. L 1 = (2 x spacing of distribution bar) + (2 x the clear cover). For longitudinal reinforcement in columns of size 200 mm and less, with 12 mm diameter bars as longitudinal steel. 9) Check for shear ( using Table 19 of code IS 456:2000). Distribution Bar = 12 Number of The Distribution Bar. 5-2 Recommended spacing of transverse. Design ProcedureAllowable clear spacing of bars = 3d = 3(170) = 510 mm Actual clear spacing = 300 – 10 = 290 mm < 3d → ok Figure 3. Base slab width b= 0. 4 and shall have a total area of not less than 0. Before calculating the cutting length, we need to calculate each part length of chair bar. 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. Concentrated reinforcement is a fixed number of bars over a parallelogram area. Use M20 Concrete and 415 steel. it's a tool to maintain the spacing between two separate layers of slabs, footing etc. Dia of Main Bar=16mm. 7. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. The reinforcing bars must extend into the slab beyond the critical section for a required length. 1 Cement 5. Distribution bars:-These bars are straight bars. bending dimensions shall be measured as shown for appropriate standard shapes. Lits-II 1. The slab is. 1 Purchaser’s tests of steel reinforcing bars 28 Section 6 Methods of testing 32 6. The use of #4 or #5 bars is at the discretion of the Structural Project Manager if both available diameters meet demand. R403. 3. 2. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. The spacing shall be less than five times the slab’s adequate depth, or 450 mm in the distribution bars. • Maximum area of main steel in slab = 4% 𝑜𝑓 𝑏𝐷 (As per ACI). (15) Step Spacing of the dowel bars. Mainly used in slab and footing, it is the most significant part of raft foundation. 2. 5. 14 x 5 x 5 = 78. 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. 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. 18/100× × 100× D = 0. 0018 times the slab's gross area, but the maximum spacing of the bars differs. >EAST side. 150m = 150 mm. As = 0. bars in two-way slabs. Main Reinforcement Bars are used to transfer the bending moment developed at the bottom of the slab. Design size and spacing of dowel bars at an expansion joint of concrete pavement of thickness 20 cm. 5. Calculation of the loads. For distribution bars, the maximum spacing is specified as 5 times the effective depth. f d n §· ¨¸ ¨¸ ©¹ ©¹ Since the required nominal moment from Section 1 (M n,reqThe Chinese code “Code for composite slabs design and construction” (CECS273:2010) states [34] that steel-bars truss can work with concrete as upper and lower bearing reinforcement in concrete, but without considering the role of steel-bars truss as a whole and bottom PSS, the bearing capacity of SBTS is calculated according to ordinary. each way at center of slab construction joint for same shall not be more than 3000mm apart. Estimation of the joint movement, is therefore, theTwo-Way Slabs 6 b- Distribution of the total factored static moment to negative and positive moments: I. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. 3. They ensure that the load is not concentrated in one area, which could cause cracking or failure. 1. 12% of cross-sectional area as distribution rebars as per. 5 Admixtures 5. The wires or bars will be lapped as follows. t + d Lsy. 3(d) and 17. 2 Spacing of longitudinal reinforcement 11. (b) One-way joist systems in accordance with 9. of main bars = Lx/Spacing + 1 = 5000/150 = 34. 12% Gross area for HYSD bars, 0. Ex. 3. Spacing: ACI Code 7. 2and3 C. No. 6 Reinforcement 5. The maximum spacing of minimum steel (distribution bars) is the lesser of 5(135) and 450 mm. design wheel load 4000 kg. Placed at a shorter span. 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 spacing < 300mm and <3*d as per Cl. No. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. for industrial slabs that carry distribution. • Maximum spacing of shrinkage or temperature bars shall not exceed the lesser of 5ℎ and 450 𝑚𝑚 • Specified concrete cover of primary reinforcement for cast-in-place slabs not exposed to weather or in contact with ground 36 mm∅ bar and smaller is 20 𝑚𝑚; and 16 𝑚𝑚 for precast slabs (see NSCP Table 420. Thus, there are three relevant issues: 1) According to ACI 318-19 Section 7. 6666666667 = 21 nos No of bars = 21nos . No. 2. Inclined length = 0. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. 4 Deck Overhangs for guidance on deck slab bars. 60. slabs) or integral with slab with depth greater of 2. 1% of the slab cross-sectional area) through sawcut contraction joints in combination with the recommended joint spacing. Calculation of number of distribution bars. , 1-hr. For distribution bars (cl. Important Points. Calculated area; 5 x d; 450mm; Diameter of bars. 4 Deck Overhangs for guidance on deck slab bars. e min = (L/500) + (D/30) ≥ 20 mm. Dual degree in Civil Engineering, and M. 1. 133 square inches per foot). So, provide spacing of distribution bar equal to. correct. Note * rationalise centre of bars in column strips T2 and B2 to 175 mm centres to suit punching shear links. 8. 3 Aggregates 5. The minimum percentage of reinforcement is 0. (c) Deep beams in accordance with 9. Calculation of number of distribution bars. 4. Most of these formulas are based on the analysis of results of tested beams or oneway slabs. advantage of the smaller lap lengths required for top slab bars. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. 2. (Rebar Calculation Formula) No. spacing of bar/prestressing strand etc. 2. 1 and 24. Additionally, the clear space between the transverse bars and lapped bars may not exceed 1. 5. HYSD bars for upto M45 grade concrete and 0. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. bar per corner 10mm Ø vert. Cutting Length: = total length — 2 x clear cover = 4000 - 2 x 20 = 3960 mm or 3. 5. 6. Bar schedule for Slab; Table 3 : Bar schedule for SlabArea of single bar = (3. What Is Bar Bending Schedule | Preparation as Per Bs 4466 | Tolerances as Per Bs 4466; Disadvantages of Dowel Bar. Slab steel bar not less than 10mm dia. One Way Slab Bar Bending Schedule Calculation. 5d = 5 * 130 = 650 mm. Spacing = 150mm c/c as per given details = (6000/150) + 1. 8. BASIC THUMB RULE FOR RETAINING WALL DESIGN-Base slab thickness not less then 0 (H= Total height of retaining wall)The bottom part of the chair bar is called the leg of the chair bar. The thickness of Slab – 150 mm. 2 to read as follows:Historically, this level of precompression was found to enhance the performance of punching shear in two-way flat slabs based on tests conducted with this level of precompression. 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. To find the Bar Bending Schedule for Slab we use the following formula, No. Reinforcement chairs should be made with a minimum of 12 mm bar. 5.