How to Design Concrete Structures to Eurocode 2 - Chapter 7 : Flat slabs and Figure 6. Design the slab using the data given below; Purpose of building – Residential. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. 1. 1000 1500 2000. reinforcing parallel to load per inch of slab width perpendicular to load / slab thickness) (steel yield stress)) f. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. Length of distribution bars = 6. What is the maximum spacing of a distribution reinforcement to be used in a one way slab as per IS 456? b. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. The length of a distribution bar in west side is the same as the east side. 6H to 0. Distribution Bar. 6. Other notations, wherever used, areQuick guide to design of one way slab – with IS Code 456:2000. 11. The wires or bars will be lapped as follows. The no. t + DChair bars are used primarily on the slab and flooring. 2 Specific requirements for QA Stockists 26 4. 2. 5. Fig. is lapped with a lower bar of 20mm dia. however with a maximum spacing of 4. The thickness of Slab – 150 mm. Provide 0. Weight of the bar as per their length and. for exterior walls or 30 in. 1. Design a one-way slab having a simple span of 3 m. 1. Spacing of main reinforcement bars = 1000/ [A st,req / Area of single bar] = 1000/[660 / 78. 667’ x 40. 60. e. 667’ x 40. Basically slab is the horizontal member which is rests on the beam section. 0020. 091 = 300. 26. 8. 5. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. 7. (table 15). 785 x d^2 = 0. 2 BS 8110-1:1997) Width of the beam = 500mm = 0. 1. , i. ,). Always main bar use in shorter span. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. 7. 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. No. 7—Reinforcement detailing 8. 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. Length of the Slab = 5 m = 5000 mm. slabs is Thickness of slab/8 14. 2. f. Unit weight for feet per metre = (D2/ 533) × L kg/ft. Step 3 – Top Distribution. As per IS 456: 2000, Cl. 5. Minimum number of reinforcing bars. 1 or the bottom bars required by 8. 2 Minimum Slab Thickness 4-1 4. 8. 2. 1. 14 x 5 x 5 = 78. 3. This reinforcement is reported in terms of area required per unit width of slab. 7. Here we have to calculate the number of main bar and distribution bar. slab along the shorter span, 3mm per meter span. Dia of Chair. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. 225m. Joints are provided in concrete pavements to control. 12: Reinforcement detail in continuous slab 3. A = roof area in square feet drained by the drainage system. 5d = 5 * 130 = 650 mm. 16. 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. How to calculate reinforcement bar spacing How to calculate Minimum Bar Spacing for Bundle Bars in Cast-in Place Concrete as per AASHTO provisions. 18/100× × 100× D = 0. Spacing = 150mm c/c as per given details = (2950/150) + 1 = 20. 12% of cross-sectional area as distribution rebars as per. Workmanship and jobsite conditions. 1. Step 1- Calculation of Numbers of Bars. Spacing Requirements. 1—Reinforcement for shrinkage and temperature. 4 and shall have a total area of not less than 0. Reading time: 2 minutes. Bending moment calculation. 133 square inches per foot). Design a one-way slab having a simple span of 3 m. 1. unless otherwise noted in plans or specifications, camber all r. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs. So maximum diameter of reinforcement bar used in 5 inch (125mm) thick. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. 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. 12. Given data: Distribution bar dia. Hence, diameter of bar, thickness of slab, effective depth and spacing are co. Tech. 6. Spacing =80mm. In this article I will explain you complete slab design as per IS 456 code by using manual method. with a banded tendon distribution is achieved without this. 5. Also useful for attaching stirrup bar effectively. As per IS 456: 2000, Cl. e. Adequacy of curing. 900 m. The main reinforcement of an RC slab consists of 10 mm bars at 10 cm spacing. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. 1. 6. >EAST side. 2. 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. (c) Distribution. Opposite length of bar = 2950. 2. AS3600-2009 P P Lsy. e. Lits-II 1. 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. 5 m. slab, shall not. 4 Spacing Between Longitudinal Bars. 2. Eurocode 2 section 9. 300 Area of bars Φ12, a=π62 = 113. 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 Maximum Distance between Bars in Tension. 36 Live load Canopy = 1. Clear Cover = 20 mm. 3—Corner restraint in slabsColumn = Self Weight x Number of floors. For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. So, Provided area of steel reinforcement, Ast=2416 mm 2. 2). 1905. So, we need to calculate the value of ‘D’. Distribution bars:-These bars are straight bars. Here, ∅ is the bar diameter. 3. Spacing should not exceed smaller these two values. where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. , 450 mm. 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. For distribution bars (cl. 2. Given the radius of relative stiffness of 90 cm. 3 of the Eurocode or Chapter 2, originally published as. Exceptions: 1. 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. It is mainly to prevent upward bending moment near the joint. 15% for Mild steel bars. Important Points. 53 Compute moments At support: ( - ) M1 = 3. 7. The maximum spacing should be reduced by a factor of 0. Spacing of chairs should be per 1 m or 1 no. anchorage to longitudinal bars and confinement of core concrete in resisting shear2. Dual degree in Civil Engineering, and M. 3. 04𝑚𝑚2 𝑎𝑏 113. The complete calculation for one way slab is explained in the below steps. As per ACI Code, In slab, minimum reinforcement shall be 0. Other Standards ACPA T 253-21 Standard Method of Test for Dowel Bars for Concrete Pavement AWWA C213-07 Fusion-Bonded Epoxy Coating for Interior and Exterior of Steel Water Pipeline (American Water Works. 6. 1. Anchor bolts are embedded into concrete a minimum of 7 inches (178 mm). 140 M. For longitudinal bars in slabs. 7. Total Length of Distribution Bars = 786. Development length = 40d. In conclusion, the efficient design of two-way slab demands following a step-by-step approach according to IS 456. Important Point: As per IS 456:2000, the limit on minimum reinforcement along either direction has been specified. (14) Step Find the load transfer capacities , , and of single dowel bar with the. and 𝑓𝑦 = 276 𝑀𝑃𝑎 for main and temperature bars. 3. For Edge Spans : Static Mom. 00mm Bottom Footing Clear Cover (F, CL). The max. Here we have to calculate the number of main bar and distribution bar. EXAMPLE: Suppose we have a one-way slab, which has a length of 5 m or a width of 2 m (clear span). 2 and 9. 8. The diameter of the chair bar = d =12mm. 1 given below. 5. Provided at the top of the slab. , B. 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. 5. C slabs. The bigger span in the above slab, 5000, divided by the shorter span, 2000, is 2. Cutting length of main bar = Clear span of slab + (2 x development length) + Inclined length – (Bend length) Clear span of slab = 2000 mmFor one way slab, distribution bars are required to tighten the main bars together – since it has only one spanning reinforcement. That is 11′. are called concrete. 12. Sketch the detail of reinforcement. Provide main reinforcement of 10 mm diameter bars at 120 mm c/c. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. The minimum cover for cast-in-place concrete is specified by the ACI 318 Building Code. 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. A s,min,reqd ≥ b*h*0. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. 5bw and 600 mm B. This method is applicable to straight and right (i. 7. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 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. 1—Minimum flexural reinforcement in nonprestressed slabs 8. First, find number of rods required for main reinforcement and distribution. Thus, there are three relevant issues: 1) According to ACI 318-19 Section 7. = 2sqm/1sqm = 2nos. Number of Main Bar & Distribution Bar: First, we have to calculate the number of bar required for the slabs. If dowel placement deviates from the desired position, it is said to be misaligned. t + D Chair bar per square meter. ment among different types of cements. For distribution bars the maximum spacing is specified as 5 times the effective depth or. 0020. Placed at a shorter span. f. Side clear cover of slab 25 mm; Thickness of slab is. 2) height of chair:- vertical distance of chair bar is known as height of chair, it is main part of calculation to find and how to calculate height of chair bar Height of chair = depth of footing _ (upper and lower clear cover of concrete + bottom. to carry a uniform live load of 7500 Pa. Minimum clear cover to reinforcements in slab depends on the durability criteria and this is. The following details are obtained from the figure-2: Length of Footing = X = 2m. 2. 4 Water 5. 2 of ACI 318-11, it should be clearly denoted on the structural drawings. S. The below specified 7 steps are generally used to design the two way slab. 3 or larger placed within the last 8 inches of each end of the lap (Figure 3). For concrete cast against and permanently. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. It is appropriate to design the slab per unit width, hence b = 1000mm. of bars= (Slab length (L)/spacing)+1 Equation 1. Bar schedule for Slab; Table 3 : Bar schedule for SlabArea of single bar = (3. Two-Way. It covers the general features of design, loads and load combinations, structural analysis, materials, fabrication, erection and maintenance. × c/c distance between the top distribution bar) + (extra length on either side of the top distribution bar)]Calculate the nos’ of facet rebar. This is plotted against the overall fire rating of the structure that is being designed. 3 Factored live load = 3. 5. 0 8 #5 12 6 5 2 4. Diameter of top and bottom distribution bars = 16 mm. 896 x Total Length (where d is in # Nos. 960m. 2. 3. This is also. As the slab is inflexibly fixed at the ends, this shrinkage will be limited by the support, which will prompt liable tensile stress in the slab. 1 Definitions 25. If it is desired to replace 10 mm bars by 12 mm bars, then the spacing of 12 mm bars should be. 3. 3. Bar Spacing According to ACI Code 7. d = Effective depth. Distribution Bar = width of the foundation – 2 CC ÷ Spacing +1. • 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. 26. 2—Minimum flexural reinforcement in prestressed slabs 8. 75 m. Head ( E ): The length of the head = [(2nos. Assume 𝑓𝑐′ = 27. 7. 5% steel (continually reinforced) as described in Section 8. d = Effective depth. Step 5 – Calculation of Steel Weight. 2. So we have total 16 nos of distribution Reinforcement bar so the total length is. Conclusion. 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. 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. Total Cutting Length Of Rod = 2nos x 1. 6. Loads which consist of any on e of the following: moving live loads exceeding a. of Main bars = 20 + 1 = 21 Nos. Radius =length /2. Thickness of Slab = 0. For rectangular footings bars in long direction should be uniformly spaced. Load Distribution. of Main bars = (3000)/150 + 1. 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. Concrete cover = 25 mm. 2 (6) Beams: the maximum longitudinal spacing between shear assemblies s l,max; 9. TRANS REINF - Reinforcement required along the transverse direction ( along local Y axis of the plates ). 40 mm or diameter of bar whichever is more 2. 26. 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. however we need to understand the requirement of chair. 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. Chair bar per square meter. #IScodes #Concrete #Concretetechnology Recent & Related Videos Concrete. Designing and drawing of flat slab with the help of i. 26. 76 Slab designation: CS1 Check if one-way or two-way slab 1 Slab is one way since it is catilever slab Minimum slab thickness min t = 69. The maximum diameter of the reinforcing bar in a slab should not exceed 1/8th of the total thickness of the slab. Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. Number of Required Bars Formula = (Length of slab / spacing) + 1. 2, also includes guidance on achieving enhanced aggregate interlock by continuing a small percentage of deformed reinforcement (0. As = 0. 090 square inches per foot of slab width, required each way. Distributed reinforcement is a bar spacing applied over a polygon area. 6—Factors affecting the construction load distribution 3. Most of these formulas are based on the analysis of results of tested beams or oneway slabs. 6—Factors affecting the construction load distribution 3. , see 10. 3 Slabs Monolithic with Supports 24. The maximum spacing of main bars is limited to 3d or 300 mm (whichever is less). 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. Total length = 3. 6. R4405. IN Downloaded from Ktunotes. correct. Earth Pressure intensity (q) = N/A prov = (18765. bar per intersection 10mm Ø vert. 4 bar at the top and the bottom. e. Main Steel Bars. 5 inches (Singh & Saini, 2019). 11in2) Spacing = As 0. Distribution bars are provided perpendicularly with the top of the main bar. 2. 2) b = edge distane of bar for calculation of lap length (cl. 4 bars in the middle third of the footing depth. One Way Slab Bar Bending Schedule Calculation. No. 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. The spacing or c/c distance of distribution bars shall not exceed the following. Number of bar = total width /spacing +1. Maximum spacing between Individual Bars: The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 2. Bar schedule for Slab; Table 3 : Bar schedule for SlabArea of single bar = (3. Longitudinal reinforcement should not be less than 0. 2 or 8. 17 The design of one-way slab is simple and can be carried out easily. 6. the constant value of 50. IF Grade 50 to 60 deformed bars or welted wire reinforcement are used9. 3. 50 8. 4 and shall have a total area of not less than 0. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm. 1 Answer. Business, Economics, and Finance. Minimum requirement in slab : As per clause 26. Different codes have different formulas to calculate crack spacing and width developed in flexural members. 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. 1905. continuous slab – code coefficients-. 15%of gross cross-sectional area if plain bars are used and 0. FIrst, find number of rods required for main reinforcement and distribution. 13. 304. 4—Openings in slab systems 8. 10 cm; 12 cm; 14. Distribution Reinforcement bar: No of bars = total span/spacing = 2960 mm/200 mm = 15. general building code. 18% for higher concrete grades. 96 x 1000 / 1536 = 130. Lapping is not allowed for the bars having diameters more than 36 mm. The spacing of the bars The length of a distribution bar on the south side will be the same as the north side. e min = (L/500) + (D/30) ≥ 20 mm. 42d. Development Length (Ld) = 40d. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. Figure-2: Distribution or shrinkage and Temperature Reinforcement Bars in One-way Concrete Slab. 18/100× × 100× D = 0. The main bars will be 12 mm in diameter @100 mm c/c spacing. M o can be distributed, according to factors given in the table 8. 1 of IS 456:2000, the reinforcement in either direction ,in slabs shall not be less than 0. 15% of the gross cross-sectional area if. Step 1: – Calculate numbers of distribution rods. however with a maximum spacing of 4. What Is The Maximum Bar Spacing In Reinforced Beams According To IS 456? Normally this. 3: Two-way slabs supported on four sides; Clause 6. 3. 10. ACI 318-19, Table 8. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 1. For Main Bar. where.