Concrete moisture conditions and drying rate. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. per Section 6. 3) For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. What is the maximum spacing of a distribution reinforcement to be used in a one way slab as per IS 456? b. Minimum area of slab reinforcement. Thus, there are three relevant issues: 1) According to ACI 318-19 Section 7. The Main bars will be 12 mm in diameter with 100 mm c/c spacing. 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. Crack Control – when crack widths are not checked by calculations No Further Checked Required. Check resistance to moment transfer from column to slab . The clear cover will be 25 mm(Top or Bottom) and the thickness of the slab is 150 mm. Maximum spacing between Individual Bars: The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Wall Load Per Running Meter. If shear reinforcement is required for in-plane strength, s shall not exceed the smallest of 3h, 18 in. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. 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. 6. 12. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. Total Length of Distribution Bars = 19. length of dowel bar and a maximum joint opening of 0. Always main bar use in shorter span. 7. Thickness of Slab = 0. 1905. 26. Provided to resist the shear stress and cracks. Unit weight formula for kg per metre = (D2/163) × L kg/m. The design of a one-way slab can be done by using the Indian standard code. Weight of the bar as per their length and diameter by following the Formula: –. The diameter of the chair bar should not be less than 12 mm. The minimum spacing between the two bars can be about 50–75 mm. 1—General 8. 25 x total length of bar. Check for Cracking. According to direct design, the balanced load, W1, and the effective prestressing, F, in a one-way slab or the beam supports for one-way slabs can be computed as t _ 48kBW + 8k f (L (3) Wl — 1 + 48kB F, = 72BW L2 + 12 f t2 (4) t(1 + 48kB) where B is the moment coefficient, M = BWL2, depending on the slabDesign of 2 way slab as per IS code. As per clause 26. ([DPSOH ± 'HWHUPLQDWLRQ RI Seismic Forces: Diaphragms of %XLOGLQJ Chapter 4 One-way Slabs 4. The minimum percentage of reinforcement is 0. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. steel bar use Top Side +28 Nos Steel use. 96 sq mm. Step 2: Preliminary dimensioning. Wood structural panels with a minimum thickness of 7 / 16 inch (11. 5. Dual degree in Civil Engineering, and M. 3 only and there is no need to perform specific checks on the bar spacings to control cracking. 2 of ACI 318-11, it should be clearly denoted on the structural drawings. 6. 15% gross c/s of slab – for MS bars; 0. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. (c) Deep beams in accordance with 9. 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. The diameter of the bars varies from 8mm to 14mm and should not exceed 1/8 th of the overall depth of. It is a useful reference for engineers, planners and contractors involved in bridge construction. 31kg says 35kg. Total Cutting Length Of Rod = 2nos x 1. The maximum spacing of main bars is limited to 3d or 300 mm (whichever is less). , addi-tional bonded shrinkage and temperature reinforcement conforming to 7. 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. The number of the bars is seventh factor taken in basic rules in column design. April 2, 2023 May 25,. DESIGN OF SLAB: Design of typical Floor Slab: We have thickness of slab as 130 mm. Distribution bar 8 mm C/C 140 mm Length 1. Calculation of the loads. Minimum number of reinforcing bars required. e. 3(d) and 17. Length of waist slab= L. 1 specifies the requirements of ACI 7. 6. Maximum size of bars in slabs As per clause 26. Cranking is also used in two way slabs. 3. Distribution bars are provided in the longer span direction. 2, 17. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs are required as per standard codes. Design the slab using the data given below; Purpose of building – Residential. Reading time: 2 minutes. Provide main reinforcement of 10 mm diameter bars at 120 mm c/c. three times the effective depth of solid slab or; 300 mm; whichever is smaller. 667’ x 40. 11. 3. Fig. Minimum requirement in slab : As per clause 26. 4—Construction load distribution 3. 15% of the total cross-sectional area of the slab (bD). Design size and spacing of dowel bars at an expansion joint of concrete pavement of thickness 20 cm. 10mm Ø hor. 12. (b) One-way joist systems in accordance with 9. C. 12% of cross-sectional area as distribution rebars as per. 3, 1) The horizontal distance between parallel main reinforcement bars shall not be more than. 7. 18D sq. Given data: Distribution bar dia. 7. 6666666667 = 21 nos No of bars = 21nos . Reading time: 2 minutes. In Flat plate slab the, distribution bars are arranged in one direction at Top of main bar (in longer span). 6 = 17 bars; The number of distribution. #IScodes #Concrete #Concretetechnology Recent & Related Videos Concrete. Distribution bars placed on top of the main bar. C. e. (b) One-way joist systems in accordance with 9. = 175 mm Last perimeter, from column face, min. 2Dead Load + 1. 6. 7. From a study that compared voided slabs and solid slabs, researchers observed that for typical bays of 7. Take à l/d as 32 for HYSD bars . Step 1 – Find out the Total Number of Main Bars & Distribution Bars. Spacing = 150mm c/c as per given details = (2950/150) + 1 = 20. 0m from the fixed end. 14 x r x r) = 3. , the effective depth is: clear spacing between layers clear cover stirrup diameter bar diameters 2 dh . For ASTM A 497 deformed welded wire fabric Values in the subgrade drag equationData of Calculate Steel in Rcc Slab-. For Edge Spans : Static Mom. 12% gross c/s of slab – for HYSD bars; Spacing of distribution bars. 3. Diameter of top and bottom distribution bars = 16 mm. 5. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. 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. a = axial spacing of the bar for calculating the lap length (ci. 5. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. Generally # 3 or # 4 bars are used for slab main reinforcement. 3 times effective depth c. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. 5% steel (continually reinforced) as described in Section 8. Ensure a minimum number of bars in a square column is 4 and in a circular column, 6. 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. 5. 4 Splices in reinforcement. 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. 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. 2 times effective depth b. 3. 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. 7. Spacing: ϕ8 mm: ϕ10 mm: ϕ12 mm: ϕ16 mm: ϕ20 mm: 100: 502 : 785: 1130: 2010: 3141: 125: 402:. shall be the lesser of (i) five times the effective depth, or (ii) 450 mm. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any value. 230/0. 25*3. The maximum spacing of bars shall not exceed. Check for the depth. k’ = 0. Only 1 D. 9. FIrst, find number of rods required for main reinforcement and distribution. FAQ . Top & bottom clear cover = 50 mm. in. 11. The code makes it explicit that the diameters of the skin bars are not involved in determining the spacing of this reinforcement. Unbonded Cross Sections" for discussion. 5 mm 2. For Min Steel: 3d ——— Where. One Way Slab Bar Bending Schedule Calculation. Bar Spacing. Weight of rod per meter length = d 2 /162 where. The new formulas are more complex and consider more parameters, such as bridge length and. 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. No. for distribution bars, steel 6 mm or 8 mm are generally used. 00mm Bottom Footing Clear Cover (F, CL). 5 m as per IRC. of Main bars = 20 + 1 = 21 Nos. (b) 18 in. Spacing = 150mm c/c as per given details = (6000/150) + 1. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. 6—Factors affecting the construction load distribution 3. 2 m), regardless of steel grade. Main Bars and Distribution Bars in Slab and Their Function. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. total angular change of tendon profile from tendon jacking end to point under considerations, radians. 12: Reinforcement detail in continuous slab 3. Number of Main Bars = (Length of Longer Side / Spacing) + 1 =. Step 1. c) Spacing of bars: The maximum spacing of bars shall not exceed Main Steel – 3d or 300 mm whichever is smaller Distribution steel –5d or 450 mm whichever is smaller Where, ‘d’ is the effective depth of slab. Table 1. Spacing =150mm. Total length of bar required for distribution bars of Floor Slab 1 = 131m. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. 1—Reinforcement for shrinkage and temperature. Load Distribution. Chair bar per square meter. ) = 200. 6. ment among different types of cements. Note * rationalise centre of bars in column strips T2 and B2 to 175 mm centres to suit punching shear links. 26. Distribution Reinforcement for Stairs. 167 for 15% redistribution. 5h ≤ 450mm (in areas of concentrated loads 3h ≤ 400mm) Where h is the. Maximum size of bars in slabs As per clause 26. 5bw and 600 mm B. how to calculate the number of rebar in an exceedingly circular block. 96 x 1000 / 1536 = 130. 5. 6. 3. 667’ x 40. Common rebar sizes range from #3 to #6 for slab footings, with #4 being the most commonly used. 5 Loads on Supporting Beams 25 COMPRESSION MEMBERS 25. 7. . 1. Transverse joint spacing should not exceed 125% to 150% of the longitudinal joint spacing. Step 2: Calculate cutting length of main bars and distribution bars. 2—Minimum flexural reinforcement in prestressed slabs 8. 4. The direction of the main bars (T1 and B1) in a flat slab system depends on various design factors such as the span length, load distribution, structural efficiency, and code requirements. slab to provide shear resistance. cb = smaller of (a) the distance from center of a bar or wire to nearest concrete surface, and (b) one-half the center-to-center spacing of bars or wires being developed, in. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Concrete moisture conditions and drying rate. 10mm Ø hor. 12% of high yield strength deformed bars. 3. 4—Construction load distribution 3. 20 square inch (129 mm 2) in cross-sectional area shall be provided: 1. t + d Lsy. 6. The number of bars is 50. Requirements regarding dowel bars and spacing of joints have been modified. 75 Nos. 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. 2. 3. 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. The minimum cover for cast-in-place concrete is specified by the ACI 318 Building Code. 5m . Two-Way. 3. Business, Economics, and Finance. 230m. Abstract. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 25 x 87. Assume 𝑓𝑐′ = 27. bar due to its non-availability. 7. Wood structural panels with a minimum thickness of 7 / 16 inch (11. There are 51 nos of main bars are required for the slab. Check spacing of bars. 3. rahuledu said: as per IS 456:2000, chair shall be fixed 1 no in 1 Sq. What should be the diameter of chair bars used in construction? Typically, chair bars are made of reinforcement with a diameter of 12 mm and above. 2. 1. 2. Cutting Length: = total length — 2 x clear cover = 4000 - 2 x 20 = 3960 mm or 3. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 1000 1500 2000. The size and spacing of S1 and S2 bars shall be determined by design. spacing of 18” d) Choose bars: For square footings use the same size and number of bars uniformly spaced in each direction (ACI 13. 3 b) 1). Spacing of bars = 180 mm c/c < 300 mm and 3d ok Distribution steel =. Bar crank. IN Downloaded from Ktunotes. , 1-hr. Full bond Full bond h/2 Filler Figure 15:3: Contraction joint 15. 8. Spacing of bar = area of a bar * width of strip / area of reinforcement required = 78. continuous slab – code coefficients-. t + d Lsy. This portion is coming at the top of the bottom main bar. 00mm Pedestal Clear Cover (P, CL) : 50. Section 8. A s,min,reqd ≥ b*h*0. In this article I will explain you complete slab design as per IS 456 code by using manual method. 9 m = 3. EXAMPLE PROBLEM 1. Calculation for distribution bar: Bending moment for distribution. 2, with “S” assumed to be equal to the length between negative moment design sections. 3) or the distance of centre of gravity of the concentrated load from the nearer support (ci. 5. 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. 12. 2. Dowel bars require care in placement to minimize. Radius = 2. 318-19 Sections 7. 53 Compute moments At support: ( - ) M1 = 3. 304. 60 kN/m. 15% for Mild steel bars. Cryptocritical section of the slab is just outside the outside edge of the beam supporting the slab. 40 mm or diameter of bar whichever is more 2. SECTION 5: CONCRETE STRUCTURES 5-5. (b) For No. 3. Cover block use 15 to 20mm. 5. 12. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. 04𝑥1000 𝑆= = = 272. 6—Reinforcement limits 8. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. 2 BS 8110-1:1997) Width of the beam = 500mm = 0. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. It is appropriate to design the slab per unit width, hence b = 1000mm. 1 Spread Box BeamsA. Designing and drawing of flat slab with the help of i. 3). On the bigger side, distribution bars are supplied, however, they will not assist in bearing any weight. 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. The size of the stirrups should be chosen to avoid a closer spacing. 33(fc') 0. This type of reinforcement is convenient for modeling layers of reinforcement over a portion or the entire slab area. For longitudinal bars in columns of size more than 200 mm. We would like to show you a description here but the site won’t allow us. 0 8 #5 12 6 5 2 4. Ex. 0018 times the slab's gross area, but the maximum spacing of the bars differs. You just enter your information in the yellow colour box for the design of two way slab excel sheet as per is 456 such as. Where a slab on ground is cast monolithically with the footing, one No. bars in two-way slabs. Since diameter of bar = 10 mm. C slabs. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. 78′ Say, 19′. This is plotted against the overall fire rating of the structure that is being designed. This reinforcement is reported in terms of area required per unit width of slab. Fig. Height of block wall = 2. How do bars spread out on slabs according to IS-Code & IF Code? The spacing between the parallel main reinforced bars for RCC is 300 mm (3D). AASHTO 5. however with a maximum spacing of 4. where is the radius of the wheel load distribution in cm and is the slab thickness in cm. 9) Prepare bar bending. 7. Ensure that the return bars at the edge of the slab are a minimum of ¼ (15%) of the length of the adjoining 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. Sub-slab details (i. 13. Calculate the quantity of. 3. member has shallow depth of less than 150 mm (ex. 3. According to ACI Code 7. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. 5. 2. (b) Horizontal reinforcement at least 0. Design Guide on the ACI 318 Building Code Requirements for Structural Concrete. 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. 3. The maximum diameter of the reinforcing bar in a slab should not exceed 1/8th of the total thickness of the slab. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. TRANS REINF - Reinforcement required along the transverse direction ( along local Y axis of the plates ). Distribution Bar. As per IS 456: 2000, Cl. Max. The manual design process included the reinforcement calculation for the main. . 7. 2. 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. 3 Direct supply of steel reinforcing bars to site by QA Manufacturer 27 Section 5 Purchasers testing 28 5. slab known as a joist system can be constructed without any shear reinforcement in the joist ribs. Use bar support in order to maintain the space between bars at the top and bottom and then the distance will be correct. for. For Main Bar. t + D Chair bar per square meter. Slab steel grid not less than Fe500. Maximum Spacing between Stirrups . The minimum spacing between the two bars can be about 50–75 mm. Placed at a shorter span.