spacing of reinforcing bars (cls. Minimum area of slab reinforcement. 7. 2. 60. , 0. Height of the footing (Thickness) = h =0. = 20 mm, spacing @ 150c/c. The Distribution bars will be 8 mm in diameter with 125 mm c/c spacing. The minimum percentage of reinforcement is 0. Distribution Bar. R-5 insulation shall be provided under the full slab area of a heated slab in addition to the required slab edge insulation R-value for slabs. 3. 9. 26. One Way Slab Bar Bending Schedule Calculation. 3. This type of reinforcement is convenient for modeling layers of reinforcement over a portion or the entire slab area. The primary reinforcing bar is placed perpendicular to the bigger side or parallel to the shorter direction to give suitable support. • Maximum area of main steel in slab = 4% 𝑜𝑓 𝑏𝐷 (As per ACI). Tayabji (1986) identified the following categories of dowelmillimetres and N represents the identification number of the bar/bars given consecutively. The Clear. 5 In walls and one‐way slabs the maximum bar spacing shall not be more than three times the wall or slab thickness h nor 450 mm. 3. Calculation of number of distribution bars. They ensure that the load is not concentrated in one area, which could cause cracking or failure. (1:1. 5. 460/2=1. Earth Pressure intensity (q) = N/A prov = (18765. Lower part bar will be worked by maintaining cover with spacer. ([DPSOH ± 'HWHUPLQDWLRQ RI Seismic Forces: Diaphragms of %XLOGLQJ Chapter 4 One-way Slabs 4. 7. Minimum Bar SpacingAs per AASHTO LRFD, section 5. Loads which consist of any on e of the following: moving live loads exceeding a. each way at center of slab construction joint for same shall not be more than 3000mm apart. Given data: Distribution bar dia. 42d. 1. The maximum diameter of the reinforcement bars in R. 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. Design of slab. Maximum spacing: The maximum spacing of main bars is limited to 3d or 300 mm (whichever. 3 only and there is no need to perform specific checks on the bar spacings to control cracking. 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. This smaller amount of reinforcement0. 3m. 9, page 341. FIrst, find number of rods required for main reinforcement and distribution. dia. 3. 3. This is also satisfied for all the bars. Now, we will calculate the length of the three parts of the chair bar separately. 10. 7. 2 times effective depth b. Placed at a shorter span. 5. No of Bars/m 2 = Factored Load / Pcr. According to ACI Code. • The. The manual design process included the reinforcement calculation for the main bars and distribution bars as per the considerations and as per the problem statement. Step 1. Step 2: Calculate cutting length of main bars and distribution bars. Step #1 – Bar Numbers. Top & bottom distribution bar dia. Continuity of reinforcement shall be provided at corners and intersections. 12% of high yield. 1. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. Beams = Self Weight per running meter. 4. 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. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. Number of Main Bar & Distribution Bar: First, we have to calculate the number of bar required for the slabs. 1 Answer. 1 General 24. = constant used to compute V c in slabs and footings. 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. 1—Early-age concrete material strength development 4. assume corners are held down. 12% Gross area for HYSD bars, 0. The distribution bars’ primary function is evenly distributing the load across the slab. 0018. In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. 376Kgs For Floor slab -2 (One way slab) :-As per the above figure Floor slab -2 is a One way slab. 14 m, and 10. 3(d) and 17. Assume diameter of bars and calculate spacing of bars. 3. 1905. Bar Spacing. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. slab to provide shear resistance. ? 1. Spacing = 150mm c/c as per given details = (2950/150) + 1 = 20. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. per Section 6. b) Slab depth does not. 6 𝑀𝑃𝑎. Calculate The Cutting Length of the Chairs Bar Given Data. For eg. (b) 18 in. 8. 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. 8. 3. 3. 300mm. Given Data: Height of footing = 600 mm. Area of One Bar 20114 Sqmm 16 RESULT Spacing of Distribution Bars 360 mm 16 from BSCE 11234 at Xavier University - Ateneo de CagayanThe maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 9) Prepare bar bending. 24. 25 in. Minimum requirement in slab : As per clause 26. 11in2) Spacing = As 0. Other notations, wherever used, areQuick guide to design of one way slab – with IS Code 456:2000. Curtailment of bars in slabs Curtailment of bars is. 54 * 1000 / 180 = 436. 002 times the gross cross-sectional area of the footing. , Chapter 12 c c = clear cover of reinforcement, in. Cranking is also used in two way slabs. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Section 8. Diameter of a chair bar should not be less than 12mm. 1% steel allows sawed contraction. 1 or the bottom bars required by 8. c 0. A review of the behaviour and design of different types of beam-column joints in reinforced concrete moment resisting frame under seismic loading illustrates that design and detailing provisions for the joints in the current Indian seismic code, IS 13920 : 1993. 5. 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. joint spacing greater than 50 ft (15. Use M20 Concrete and 415 steel. 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. 2Dead Load + 1. Unit weight of concrete = 25 kN/m 3. 67’ Weight of Distribution Bars = d 2 /52. 2. Minimum Bar Size : 16 mm Maximum Bar Size : 25 mm Top Footing Minimum Bar Size : 16 mm Top Footing Maximum Bar Size : 25 mm Pedestal Minimum Bar Size : 16 mm Pedestal Maximum Bar Size : 25 mm Minimum Bar Spacing : 100. purchase orders, drawings, or per diems shall be done at the risk of those making such references or quotation. 12, apply only to one-way slabs (all code sections cited hereinafter are from ACI 318-08): “7. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. slabs) or. 3-Main bar Bottom Area Given data. from deviations in bar spacing and bar size are shown in figure 5. Step 1. 6. No Of Bars Required For Cutting Distribution Bars. where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm. Distribution Bars are used to hold the slabs on either way and to resist the cracks. rahuledu said: as per IS 456:2000, chair shall be fixed 1 no in 1 Sq. Spacing of main reinforcement bars = 1000/ [A st,req / Area of single bar] = 1000/[660 / 78. 3. The distribution bars should be (2000- 2 x 25) /125 + 1. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. Provided at the bottom of the slab. 7. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. First, find number of rods required for main reinforcement and distribution. 6. 1 Spacing s of longitudinal bars in cast-in-place walls shall not exceed the lesser of 3h and 18 inches. 4. iv) Detrmine Sapcing of bars at critical section based on designed value of Ast by selecting appropriate bar dia. 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. 40 mm or diameter of bar whichever is more 2. unless otherwise noted, all slabs on grade are to be reinforced with 10mm bars at 400mm o. As = 0. As always, local service records are the best guide for determining trans verse joint. 2. 3. 304. Spacing =80mm. Fig. C. f ck = 25 Mpa. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 7. The larger the diameter of the bar, the more the spacing is, and vice versa. for distribution bars, steel 6 mm or 8 mm are generally used. 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. 14 x 5 x 5 = 78. correct. 304. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. 2 of IS 456) shall not exceed 140/8 = 17 mm is also satisfied with the bar diameters selected here. Design the slab using the data given below; Purpose of building – Residential. 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. , and if the lap length is taken as 50d, then. Since diameter of bar = 10 mm. 2. 4 bars in the middle third of the footing depth. 9. As per IS code, the minimum grade of concrete for the design of a Pre-tensioned concrete structure is:-M20; M25; M40; M30;Cutting Length of Foundation Distribution Bar. 3. L 1 = (2 x spacing of distribution bar) + (2 x the clear cover). member has shallow depth of less than 150 mm (ex. What Is The Maximum Bar Spacing In Reinforced Beams According To IS 456? Normally this. 2 to read as follows:Top & bottom distribution bar dia. (Main Bar & Distribution Bar Difference) Top and Bottom Clear Cover is 25 mm. The spacing of distribution bar should not be greater than 5 times the effective thickness of slab or 450mm whichever is smaller. Calculation of area of steel. 6m . ,). 6 = 17 bars; The number of distribution. 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. 36 Live load Canopy = 1. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any value. 11. The main reinforcement of an RC slab consists of 10 mm bars at 10 cm spacing. 3 Dowel bars The purpose of the dowel bar is to e ectively transfer the load between two concrete slabs and to keep the two slabs in same height. Also useful for attaching stirrup bar effectively. 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. 12 x 100cm x D cm=0. to carry a uniform live load of 7500 Pa. 4. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. Height of block wall = 2. 75H for surcharged wall. 7 For temperature steel only, maximum spacing shall not exceed five times the slab thickness h nor 450. 4 must be met, and max. For concrete cast against and permanently. According to ACI Code 7. M o can be distributed, according to factors given in the table 8. t + DChair bars are used primarily on the slab and flooring. Spacing of bar supports depends upon the size of the reinforcing bar being. 1 or the bottom bars required by 8. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. Radius =length /2. bars are used as distribution bars and are placed at 30 cm centres at the top of the bottom bars. Provided to resist the shear stress and cracks. how to calculate the number of rebar in an exceedingly circular block. Clause 6. in. 4. c) Slab reinforcement percentage less than 0. 1. 12% of cross-sectional area as distribution rebars as per. L is the required length of the Steel bar of Diameter D. Step Assume load capacity of dowel bar is 40 percent wheel load, find the load capacity factor f as. The size of the stirrups should be chosen to avoid a closer spacing. Conclusion. AS3600-2009 P P Lsy. For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. Placed at a shorter span. 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. 3. 1. Concrete cover = 25 mm. Conclusion. It is a two way slab. Main Reinforcement bars are placed in shorter direction and Distribution bars placed in longer span direction. *A4 size is 210 x 297 mm. That is 11′. 4. Given the radius of relative stiffness of 90 cm. exposed to earth or weather. 3. cm. For structural slabs of uniform thickness the minimum area of tensile reinforcement in the direction of the span is: For US-units: IF Grade 40 to 50 deformed bars are used. 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. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. For. If dowel placement deviates from the desired position, it is said to be misaligned. 1 In slabs, beams and girders, splices in reinforcement at points of maximum stress shall be avoided wherever possible. = 16 mm, spacing @ 150 c/c. 5 Loads on Supporting Beams 25 COMPRESSION MEMBERS 25. , B. Different codes have different formulas to calculate crack spacing and width developed in flexural members. 2. 17 The design of one-way slab is simple and can be carried out easily. Reinforcing Bars for Crack Control 6-33 Distribution of Tension Reinforcement in. 1% of the slab cross-sectional area) through sawcut contraction joints in combination with the recommended joint spacing. Note: When ACI 318-19 is selected, an additional size effect factor λs is added in the above equations, λs is a function of effective depth of the slab d, and is calculated per Equation (22. Number of bar = 2150/150+1= 15. Minimum S&T reinforcement quantities required by ACI 350-01 and As per IS 456:2000, in rcc slab, maximum diameter of main bar and distribution bar should not exceed 1/8th thickness of slab. ACI 7. Unbonded Cross Sections" for discussion. C. 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 ). 4 and shall have a total area of not less than 0. Generally # 3 or # 4 bars are used for slab main reinforcement. 0104 Ai. 2. 1 of EC2, the recommended minimum spacing of reinforcing bars is 75 mm and 100 mm for laps. 25 8 #5 12 6 6 2 4. Minimum spacing for distribution bars is, (1) 5d = 5 X 76 = 380 mm (2) 450 mm . 1. 5 The lateral spacing of temperature and shrinkage reinforcement should not be placed farther apart than 5 times the slab thickness or 18 inches according to ACI code 7. 7. 18/100× × 100× D = 0. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /3. 8. Adequacy of curing. Is 1200 Important Point Part-1; IS Code for Civil Engineer [Q&a]. 3. Cranking is also used in two way slabs. c. 2. 3. BS EN 1992–1–1 section 6. 1 of code IS 456:2000. 4 bar at the top and the bottom. In Flat plate slab the, distribution bars are arranged in one direction at Top of main bar (in longer span). Where a slab on ground is cast monolithically with the footing, one No. 5. 3 Slabs Monolithic with Supports 24. vapor retarders - some times referred to as vapor barriers, insulation, etc. 5. IF Grade 50 to 60 deformed bars or welted wire reinforcement are used9. 23 Total factored load = 6. . For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm. f ck = 25 Mpa. 5. 7. 5. So, provide spacing of. of bars= (Slab length (L)/spacing)+1 Equation 1. A cantilever slab 200 mm thick is 1. 1. S. 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 318-14, Building Code Requirements for Structural Concrete and Commentary. 15%of gross cross-sectional area if plain bars are used and 0. 5 M from the edge of wall and at both ends 6 mm plain M. Note that required A s must be furnished in each direction. Check resistance to moment transfer from column to slab . 5. 3. 3 of IS 456) 20 KTUNOTES. = 2sqm/1sqm = 2nos. Diameter of main bar=10mm. Check spacing of bars. 25 x 87. 75 m. 1. . Spacing should not exceed smaller these two values. 785 x d^2 = 0. It brings economy to the design of. Whichever is smaller,. 8. 2. TRANS REINF - Reinforcement required along the transverse direction ( along local Y axis of the plates ). 3 Factored live load = 3. Tech. Design of the footing cantilever slab portion (per meter strip) Note that the bending moment in the slab is maximum. 7. The “D” bars shown in the tables conform to Article 9. In conclusion, the efficient design of two-way slab demands following a step-by-step approach according to IS 456. 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. 1 of IS 456), the maximum spacing is the. Maximum diameter of the bars (cl. 5d = 5 * 130 = 650 mm. total angular change of tendon profile from tendon jacking end to point under considerations, radians. 5% or 0. (a) for a distance equal to the larger lateral dimension of the column above and below a beam or slab, andThe complete column design process as per IS code is determined by using below 3 basic formulas. 1. 7. Chair bar per square meter. So, Provided area of steel reinforcement, Ast=2416 mm 2. Distribution bars are provided perpendicularly with the top of the main bar. 2. Near lapped joints, if the diameter of the longitudinal bar is greater than 14 mm. Maximum size of bars in slabs As per clause 26. Total length = 3. Maximum spacing of bars for slabs • Main bars: 3h ≤ 400mm (in areas of concentrated loads 2h ≤ 250mm) • Secondary bars: 3. Minimum number of reinforcing bars. 2R-8 4. c. Calculated area; 5 x d; 450mm; Diameter of bars. 7. 5. 2 For one-way shallow foundations, two-way isolated footings, or two-way combined. 78′ Say, 19′. Size of the bar is less than the main bar. C. f yk = 460 Mpa. 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 introduces a new requirement for barBridge Deck Slab Design Example as per IRC Indian Codes, Deck Slab Bridge Design are described step by step by Using Limit State Method. The design method is followed as per Annexure D of IS 456:2000. 1—Minimum flexural reinforcement in nonprestressed slabs 8. There are 51 nos of main bars are required for the slab. BS EN 1992-1-1 Annex 1 1. 1 — Area of shrinkage and temperature reinforcement shall provide at least the following ratios of reinforcement area to gross concrete area, but not less than 0.