Reinforcing Bars for Crack Control 6-33 Distribution of Tension Reinforcement in. c) Slab reinforcement percentage less than 0. 3 Direct supply of steel reinforcing bars to site by QA Manufacturer 27 Section 5 Purchasers testing 28 5. Since diameter of bar = 10 mm. M o can be distributed, according to factors given in the table 8. (b) One-way joist systems in accordance with 9. 2Dead Load + 1. 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. 24. In Flat plate slab the, distribution bars are arranged in one direction at Top of main bar (in longer span). Distribution of Main Bars. t + D Chair bar per square meter. a) Slab depth does not exceed 250mm when the steel grade is 250. 5% or 0. Sub-Grade and. The slab is supported all around walls of width 300 mm. 1 of IS 456), the maximum spacing is the lesser of 3d and 300 mm i. 2 (6) Beams: the maximum longitudinal spacing between shear assemblies s l,max; 9. (b) 18 in. 15% gross c/s of slab – for MS bars; 0. is for dowel diameters to be one-eighth of slab thickness, dowel spacing to be 12 in. 2). How to calculate bar Bending Schedule for Slab? One way slab Reinforcement Detailing. 2. Anchor bolts are embedded into concrete a minimum of 7 inches (178 mm). 3. 1. 5. 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. The distribution bars provide the following functions in slab construction: 1. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm. 3 – When spacing of tendons exceeds 54 in. 0014: (a) Slabs where Grade 40 or 50 deformed bars are used: 0. Distribution steel –5d or 450 mm. This spacing should be reduced by a factor of 0. length of. 5bw and 600 mm B. 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. e min = (L/500) + (D/30) ≥ 20 mm. Mild reinforcing bars shall have minimum clear spacing of at least 2 in. 7. Provided spacings, therefore, satisfy the requirements. 1. 3. 7. Minimum number of reinforcing bars. 2. 8 ACI 318 , Section 17. So maximum diameter of reinforcement bar used in 5 inch (125mm) thick. Anchor bolts are located a minimum of 1 3 / 4 inches (45 mm) from the edge of the concrete parallel to the length of the wood sill plate. To firmly hold the main bars in their. Reading time: 2 minutes. of Main bars = (Width of Slab/Spacing) + 1. 64 2 )/8 = 23. cm. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 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;. anchorage to longitudinal bars and confinement of core concrete in resisting shear2. 1 (2) states that, distribution should minimum 20% of the main reinforcement. Design the slab using the data given below; Purpose of building – Residential. 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. 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. About this chapter: Chapter 3 covers general regulations for plumbing installations. Provided at the top of the slab. (1:1. 2. 960 x 16 =. 2(5)In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. 5, the lateral spacing of the flexural bars should not exceed three times the thickness of 18 inches. 6. Unit weight for feet per metre = (D2/ 533) × L kg/ft. 3(1) of EC2 for slabs not exceeding 200mm in overall depth and not subjected to significant axial tension the maximum limit on centre to centre bar spacing is governed by clause 9. 6H to 0. of Main bars = (3000)/150 + 1. 8 of BS EN 1992-1-2 Eurocode 2: Design of concrete structures – Part 1-2: General rules – Structural fire design provides data which can be used to determine the thickness and cover requirement for concrete elements. 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. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm. What is the maximum spacing of a distribution reinforcement to be used in a one way slab as per IS 456? b. Load Calculation: Live Load = 2 kN/m 2. Concrete cover to main reinforcing bars shall be provided per AASHTO Table 5. Consider 28 Nos. Length of the Slab = 5 m = 5000 mm. 3. 7. 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. Distribution Bar = 10 mm, Spacing – 150 mm c/c, Alternate bent up. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any. 3. correct. 1. 5. Loads which consist of any on e of the following: moving live loads exceeding a. This is also satisfied for all the bars. 2—Construction load factorsThe diameter of the main bar should not be less than 8mm for the HYSD bar and 10mm for plain bars. 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. SECTION 5: CONCRETE STRUCTURES 5-5. 200= 6. 5. 1. 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. are called concrete. Chapter 9 which is also per mitted per ACI 349-06 Appendix D. Before calculating the cutting length, we need to calculate each part length of chair bar. assume corners are held down. 5. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. 960m. Concrete Reinforcement January 2008 15-3. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. 00 P Flag question The maximum spacing of the distribution bar in the one-way slab must be 450 mm or less than Select one: : a. , addi-tional bonded shrinkage and temperature reinforcement conforming to 7. The spacing of the bars The length of a distribution bar on the south side will be the same as the north side. 9 Factored loads Factored dead load = 3. 12% of the gross cross-sectional area if HYSD bars (Fe 415) are used. According to ACI Code 7. where. 6 bars shall not be used for S1 and S2 bars due to interference with strands and other reinforcement. to carry a uniform live load of 7500 Pa. Fig. 305. 2. bar. Sketch the detail of reinforcement. 3. C. 96 x 1000 / 1536 = 130. The Clear cover will be 25 mm (Top or Bottom) and the thickness of the slab will be 150 mm. 2 (8) Beams: the maximum transverse spacing of the legs in a series of shear links s t,max; 9. 89 M. The shear resistance in a R. 3. Two way slab building. There are also new provisions for integrity reinforcement. Weight of rod per meter length = d 2 /162 where. Ex. 12: Reinforcement detail in continuous slab 3. 17 The design of one-way slab is simple and can be carried out easily. In the. They ensure that the load is not concentrated in one area, which could cause cracking or failure. The distribution bars are arranged to retain the mesh in perfect place and sustain the center to center c/c, bars. 8. the value of the calculated k is far below the limiting k’ for slabs. Practical considerations of one-way slab • Spacing shall be between 150-200 mm (main bars) • Spacing shall be between 150-300 mm (distribution bars)Bar Bending Schedule for Two Way Slab. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. Number of Main Bar & Distribution Bar: First, we have to calculate the number of bar required for the slabs. 5 h Finding out bar spacing: Let us chose # 3 bar (0. Spacing of main reinforcement bars = 1000/ [A st,req / Area of single bar] = 1000/[660 / 78. Thickness of the slab=l x /32= 98. Sawcut Joints A typical SOG includes three different types of joints, described in detail in ACI 360R Chapter 5. For eg. 3. 2. 6. FIrst, find number of rods required for main reinforcement and distribution. C. 7 For temperature steel only, maximum spacing shall not exceed five times the slab thickness h nor 450. Roof drainage system (Adapted from the International Code Council). , Chapter 12 c c = clear cover of reinforcement, in. 5. C. normally lower dia rebar tends to more sagging while placing in top layer. áTie the bars at the top and the bottom irrespectively. 2 Spacing of longitudinal reinforcement 11. Calculation of no of bars required in slab reinforcement Number of bars = length of lab/spacing +1. 7. 7. 2 and 9. 3(d) and 17. 6. Bar Spacing. The manual design process included the reinforcement calculation for the main. . A = roof area in square feet drained by the drainage system. 6H to 0. B. The “D” bars shown in the tables conform to Article 9. The spacing of distribution bar should not be greater than 5 times the effective thickness of slab or 450mm whichever is smaller. 12, apply only to one-way slabs (all code sections cited hereinafter are from ACI 318-08): “7. Spacing should not exceed smaller these two values. 9. 8. . Factor affecting spacing of chair bars. Note * rationalise centre of bars in column strips T2 and B2 to 175 mm centres to suit punching shear links. Tech. Common rebar sizes range from #3 to #6 for slab footings, with #4 being the most commonly used. 3. 7. A cantilever slab 200 mm thick is 1. Bar Bending Schedule Of Slab (Two Way) Ly/Lx = Longer span/Shorter span = 5000/3000 = 1. Distribution of Main Bars. Distribution Bar. 230/0. 2 of ACI 318-11, it should be clearly denoted on the structural drawings. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. 3. and 𝑓𝑦 = 276 𝑀𝑃𝑎 for main and temperature bars. AASHTO 5. 6. 347. 5 bar or two No. The wires or bars will be lapped as follows. 2, 17. 26. slabs) or. 5 bars required by 14. 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. The minimum cover for cast-in-place concrete is specified by the ACI 318 Building Code. 4. The cement content of concrete should be kept as low as possible by good grading of the aggregates. 08 times the gross area of the column. e. (b) Horizontal reinforcement at least 0. According to ACI Code 7. 12. The main conclusions can be summarized as follows: • The proposed method gives a good estimate for crack. Check for Cracking. 25 x 87. of bars = { (L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8. To find the Bar Bending Schedule for Slab we use the following formula, No. The maximum spacing of minimum steel (distribution bars) is the lesser of 5(135) and 450 mm. 3% (100As/bd < 0. bar per intersection 10mm Ø vert. 3. For Edge Spans : Static Mom. Adopt a clear cover of 20 mm and 8 mm diameter bars. Every alternate bar is cranked up to 0. (c) Deep beams in accordance with 9. f ck = 25 Mpa. Length of waist slab= L. 5 m as per IRC. 1905. However, it is not a code, so many engineers do use portions of ACI 318 on their projects. Additionally, the clear space between the transverse bars and lapped bars may not exceed 1. 3 Slabs Monolithic with Supports 24. 7. 1. Total length of bar required for distribution bars of Floor Slab 1 = 131m. If the reinforcing bars do not extend beyond the critical section. 4 bars in the middle third of the footing depth. 1 of IS 456), the maximum spacing is the lesser of 3d and 300 mm i. s code Sandeep Yadav. This type of reinforcement is convenient for modeling layers of reinforcement over a portion or the entire slab area. Assume 𝑓𝑐′ = 27. Table 1. 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. 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. 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. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. Abstract. e. The Clear. 2 – Spacing of tendons shall not exceed 6 feet. 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. Bar crank. 7. Continuously at structurally connected roof and floor levels and at the top of walls. The design of a one-way slab can be done by using the Indian standard code. The reinforcing bars must extend into the slab beyond the critical section for a required length. 6. Continuity of reinforcement shall be provided at corners and intersections. Distribution Reinforcement for Stairs. slab known as a joist system can be constructed without any shear reinforcement in the joist ribs. Given, Length of longer span = 5000 mm. 15%of gross cross-sectional area if plain bars are used and 0. In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. Suppose we have a one way slab,which having a length 5 m or width 2 m (clear span). 0. 3. 2. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. bending dimensions shall be measured as shown for appropriate standard shapes. Distribution bar = 8mm@150mm c/c. Effective Depth: (130-15-10/2) = 110 mm. 1. (15) Step Spacing of the dowel bars. 25 x total length of bar. And depth of check is determined as per IS 456 standards. Q) Calculate the quantity and weight of steel rod in a one-way slab having length 6 m, width 2. 3. Minimum Reinforcement Ratio in Slabs. If it is desired to replace 10 mm bars by 12 mm bars, then the spacing of 12 mm bars should be. Bending moment calculation. 2, 17. 6. Calculation for distribution bar: Bending moment for distribution. 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. For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. According to Clauses 8. 6. member has shallow depth of less than 200 mm (ex. t + d Lsy. Design of slab. Waist slab Bar Bending Schedule. 4 bar at the top and the bottom. Longitudinal reinforcement should not be less than 0. 7. The spacing of distribution bar should not be greater than 5 times the effective thickness of slab or 450mm whichever is smaller. Distribution Bar = width of the foundation – 2 CC ÷ Spacing +1. 7. bars are used as distribution bars and are placed at 30 cm centres at the top of the bottom bars. Number of bar =radius /spacing. 3. R4405. Bar Spacing According to ACI Code 7. Cover block use 15 to 20mm. Lap length 50d = 50 × 16mm = 800mm. member has shallow depth of less than 150 mm (ex. 20 square inch (129 mm 2) in cross-sectional area shall be provided: 1. 3, 1) The horizontal distance between parallel main reinforcement bars shall not be more than. 11. 1. 785 x 16^2 = 200. This smaller amount of reinforcement0. 6 = 17 bars; The number of distribution. Now, we need to replace the distribution bar of 10mm. Distribution bar 8 mm C/C 140 mm Length 1. Distributed reinforcement is a bar spacing applied over a polygon area. length of dowel bar and a maximum joint opening of 0. 2. c 0. 3. 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. member :. Unit weight formula for kg per metre = (D2/163) × L kg/m. 2. 0018. 2 – Spacing of tendons shall not exceed 6 feet. 3. There is two spacing between 3 reinforcement and 50 mm length both side of 1st and 3rd reinforcement used in footing. (i) The pitch of the main tensile bars in R. 5 try 100 mm Dead load Slab weight = 2. The clear cover will be 25 mm(Top or Bottom) and the thickness of the slab is 150 mm. For distribution bars, the maximum spacing is specified as 5 times the effective depth. Given the radius of relative stiffness of 90 cm. The slab has to carry a live load of 4 KN per meter square. 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. 11in2) Spacing = As 0. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. The diameter of the chair bar should not be less than 12 mm. Sub-Grade and. 5. LL = 6. For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. bars at every 3 layers of chb finished surface corner wall detail 1 - 10mm Ø vert. Inclined length = 0. 8. 12. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. 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. 6. 2(5)4. 715m long, and it is supporting a blockwork load at 1. 42d. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. in. The design method is followed as per Annexure D of IS 456:2000. slab, shall not. 7 Storageof MaterialsThere are 2 types of bars in two-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;. 96 sq mm. (b) One-way joist systems in accordance with 9. 1. per 1 m 2. No. f yk = 460 Mpa. as indicated in the table. For longitudinal bars in slabs. 5. Head ( E ): The length of the head = [(2nos. 10. Here we have to calculate the number of main bar and distribution bar. 1,2 and 3 B. Placed at a longer span.