1-3). 5bw and 600 mm B. 3. 2). 1. Generally # 3 or # 4 bars are used for slab main reinforcement. 2 SOLID SLABS SPANNING IN TWO DIRECTIONS When a slab is supported on all four of it sides it effectively spans in both directions, and it is sometimes more economical to design. 376Kgs For Floor slab -2 (One way slab) :-As per the above figure Floor slab -2 is a One way slab. 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. 5. In the. The format for each example follows the format of the ACI Design Handbook, SP-17, and provides a reference to the Code paragraph for each calculation procedure. Considering M20 grade of concrete and Fe 500 steel of diameter of 10 mm. 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. 1 of IS 456:2000, the reinforcement in either direction ,in slabs shall not be less than 0. 1% steel allows sawed contraction. Check for Cracking. The use of #4 or #5 bars is at the discretion of the Structural Project Manager if both available diameters meet demand. For ASTM A 497 deformed welded wire fabric Values in the subgrade drag equationData of Calculate Steel in Rcc Slab-. 11. In this kind of. 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. b. 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. It is also important to keep slabs as square as possible. Fig. 3. Concrete cover = 25 mm. For a given area of tension steel areas, the distribution of steel reinforcement affects. C. 25 x 87 =34. The following minimum limitations relating to various structural components shall be followed: Thickness of top flange : 100 mm. 3. Design ProcedureAllowable clear spacing of bars = 3d = 3(170) = 510 mm Actual clear spacing = 300 – 10 = 290 mm < 3d → ok Figure 3. In conclusion, the efficient design of two-way slab demands following a step-by-step approach according to IS 456. Reading time: 2 minutes. Cranking is also used in two way slabs. , 0. R4405. from deviations in bar spacing and bar size are shown in figure 5. A cantilever slab 200 mm thick is 1. 36 Live load Canopy = 1. There is two spacing between 3 reinforcement and 50 mm length both side of 1st and 3rd reinforcement used in footing. 3. Distribution steel: 0. spacing of bars should not be more than. 5 Spacing limits and concrete cover for reinforcement shall be shown on the design drawings. 3 of IS 456). STEP. 7. 25*3. Maximum size of bars in slabs As per clause 26. 12. (b) Horizontal reinforcement at least 0. 21. Dual degree in Civil Engineering, and M. exposed to earth or weather. As per clause 26. 3) For distribution bars, the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is smaller. 2, can form no closer to the facesee table 3 for spacing. 5 bar is permitted to be located at either the top of the slab or bottom of the footing. Now assume diameter of bars and calculate spacing between bars. 12. Sub-slab details (i. Distribution bar 8 mm C/C 140 mm Length 1. Now, we will calculate the length of the three parts of the chair bar separately. The maximum reinforcement ratio for columns is 0. 5. The max. 3, the maximum spac- 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. Wood structural panels with a minimum thickness of 7 / 16 inch (11. The shear resistance in a R. 2 and 9. 7—Reinforcement detailing 8. 6H, and 0. 4 mm. Joints are provided in concrete pavements to control. The continuous vertical bar required beside an opening is permitted to substitute for one of the two No. 4. The maximum spacing of reinforcement in slabs is 3d or 300mm(minimum of both). No. 2 or 8. with 12mm. 1. Number of bar = 2150/150+1= 15. Different codes have different formulas to calculate crack spacing and width developed in flexural members. 2. Length of the Slab = 5 m = 5000 mm. 6. C. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. 2. Length of distribution bars = 6. 26. 7. 1. 002 times the gross cross-sectional area of the footing. maximum spacing of reinforcement in slab as per is code the maximum spacing between two parallel main reinforcing bars in case of RCC Slab shall be 3d or 300 mm or whichever is less. 5. How to calculate bar Bending Schedule for Slab? One way slab Reinforcement Detailing. Head ( E ): The length of the head = [(2nos. 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 distribution bars should not be under 8 mm in a diameter or not in excess of 1/8 of the thickness of the R. 3m. 1—Early-age concrete material strength development 4. 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. 14 x r x r) = 3. 5. 900 m. Sketch the detail of reinforcement. 7. 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. Refer to EN 1994-2, Clauses 6. 4. Factor affecting spacing of chair bars. No. Crack Control – when crack widths are not checked by calculations No Further Checked Required. 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. 1. The reinforcing bars must extend into the slab beyond the critical section for a required length. 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. 3 Direct supply of steel reinforcing bars to site by QA Manufacturer 27 Section 5 Purchasers testing 28 5. 6 in the following cases; In sections within a distance equal to 4 × thickness of wall above or below a beam or slab. 5. 12D Sq. Slab Thickness = 150 mm. As per ACI Code, In slab, minimum reinforcement shall be 0. 7. Calculation for distribution bar: Bending moment for distribution. 5φVc except for the following cases: A. iv) Detrmine Sapcing of bars at critical section based on designed value of Ast by selecting appropriate bar dia. The flow rate, Q, in gallons per minute, can be computed as follows: Q (gpm) = 0. e. advantage of the smaller lap lengths required for top slab bars. 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. = constant used to compute V c in slabs and footings. 200= 6. 3. , if the upper bar of 16mm dia. 0018. Provided at the top of the slab. 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. The span requirement for the slabs is given by ACI Code 8. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. ( IS: 456-2000 ). The maximum anchor nominal diameter is 5 / 8 inch (16 mm). Calculation of number of distribution bars. 25 kN/m 2. Fig. 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. = 16mm, spacing @ 150 c/c. 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. continuous slab – code coefficients-. 78′ Say, 19′ >WEST side. The spacing of the chair bars depends on several factors which are listed below: – Diameter of the bar used in making a chair. slabs) or. 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. 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. 5 h Finding out bar spacing: Let us chose # 3 bar (0. BS EN 1992–1–1 section 6. Minimum clear cover to reinforcements in slab depends on the durability criteria and this is. Particular care isIRC SP 066 : 2016 is a standard specification and code of practice for the design of steel pedestrian and cycle bridges in India. 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. 25 x total length of bar. 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. 3. 3, 1) The horizontal distance between parallel main reinforcement bars shall not be more than. BS EN 1992–1–1 section 7. In Flat plate slab the, distribution bars are arranged in one direction at Top of main bar (in longer span). 5. Current recommended. 2. 3. 60 kN/m. SECTION 5: CONCRETE STRUCTURES 5-5. the constant value of 50. 8. A cantilever slab 200 mm thick is 1. 2. (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. 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. 1. 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. length of dowel bar and a maximum joint opening of 0. The Clear. EXAMPLE PROBLEM 1. In ACI 350R-89, the recommended minimum S&T reinforcement for walls with movement joint spacing greater than 60 ft (18. the joint spacing should be 24 to 30 times the pavement thickness with a maximum spacing of 15 ft (4. 2. LL = 6. . The slab requires 51 main bars. 1. Fig. 2 of ACI 318-11, it should be clearly denoted on the structural drawings. Minimum Reinforcement Ratio in Uniform Footing. Total Length of Distribution Bars = 786. 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. 10mm Main Bars @ 150mm C/C spacing; 10mm Distribution Bars @ 200mm C/C Spacing; Development Length L d = 40d; Top Extra Bar 8mm @ 150 mm c/c (both direction) Bar Bending Schedule for Two Way Slab. 1—Minimum flexural reinforcement in nonprestressed slabs 8. however with a maximum spacing of 4. 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. Opposite length of bar = 2950. Basic considerations. 2 MineralAdmixtures 5. 14. The minimum percentage of reinforcement is 0. 2 of IS 456 :2000 , the reinforcing bars shall not exceed 1/8 of theHow to Design Concrete Structures to Eurocode 2 - Chapter 7 : Flat slabs and Figure 6. 19. Dia of Main Bar=16mm. 5tf or 0. Minimum number of bars for a square column are 4 and for circular column are 6. (b) One-way joist systems in accordance with 9. Lower part bar will be worked by maintaining cover with spacer. exposed to earth or weather. The maximum spacing of bars shall not exceed. ACI 360R, Section 6. Important Point: As per IS 456:2000, the limit on minimum reinforcement along either direction has been specified. Slab steel bar not less than 10mm dia. 5 m as per IRC. 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. Main Bar = 12 mm, Spacing – 150 mm c/c, Alternate bent up. 12. Some discussion to decide about max spacing: AS per IS 456: Maximum spacing for bars in beams is 180mm for Fe415 grade and 150mm for Fe 500 grade reinf. . Maximum spacing of bars for slabs • Main bars: 3h ≤ 400mm (in areas of concentrated loads 2h ≤ 250mm) • Secondary bars: 3. 6. (b) For No. 2. Wood structural panels with a minimum thickness of 7 / 16 inch (11. 2 or 8. 1. 31kg says 35kg. member :. Fig. Before calculating the cutting length, we need to calculate each part length of chair bar. 7. So No, of 8 mm Steel bar = 3. 1 General 24. Anchor bolts are embedded into concrete a minimum of 7 inches (178 mm). 3: Two-way slabs supported on four sides; Clause 6. Is 1200 Important Point Part-1; IS Code for Civil Engineer [Q&a]. 7. 2—Construction load factorsThe diameter of the main bar should not be less than 8mm for the HYSD bar and 10mm for plain bars. Actual variety of 1 sides rebar =Number of main bar – rebar of the middle. 667’ x 40. 9. Also useful for attaching stirrup bar effectively. Thickness of the slab=l x /32= 98. ? 1. 4—Construction load distribution 3. Additionally, the clear space between the transverse bars and lapped bars may not exceed 1. If the maximum diameter for. 1. *A4 size is 210 x 297 mm. 27. 2, with “S” assumed to be equal to the length between negative moment design sections. 3 through the column, at least two post-tensioned tendons or two bonded bottom bars or wires in each direction shall pass through the lifting collar as close to the column as practicable. 25 x 87. Bar cranking is the process of bending up the bottom steel bars in upward direction. 3. You can design the two way slab using our android application. The thickness of Slab – 150 mm. dia. c. M255M/M 255 (2019) Standard Specification for Steel Bars, Carbon, Hot-Wrought, Special Quality, Mechanical Properties M 334M/334 (2017) Standard Specification for Uncoated, Corrosion-Resistant, Deformed and Plain Chromium Alloy, Billet-Steel Bars for Concrete Reinforcement and Dowels T 253-02 (2016) Standard Method of Test for Coated Dowel. 26. 5. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. 3. Distribution Reinforcement for Stairs. slabs is Thickness of slab/8 14. Distribution of Main Bars. 3. For Min Steel: 3d ——— Where. 975 KN)/ (39. What is the maximum spacing of bars in slab? 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. 715m long, and it is supporting a blockwork load at 1. 19 or greater, the minimum concrete cover is 5 cm. 0018 times the slab's gross area, but the maximum spacing of the bars differs. 5 and 6. Provide main reinforcement of 10 mm diameter bars at 120 mm c/c. 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. The spacing or c/c distance of distribution bars shall not exceed the following. Concrete Slab Design ProcedureSteel reinforcements can be use, however with a maximum spacing of 4. M. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. 2 to read as follows:Top & bottom distribution bar dia. 1. 090 square inches per foot of slab width, required each way. unless otherwise noted in plans or specifications, camber all r. 5. Collectors, Chords and ConnectionsIS Code. Cranking is also used in two way slabs. 7—Post-tensioning load redistribution Chapter 4—Strength adequacy of concrete slabs and formwork, p. 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. ([DPSOH ± 'HWHUPLQDWLRQ RI Seismic Forces: Diaphragms of %XLOGLQJ Chapter 4 One-way Slabs 4. e min = (L/500) + (D/30) ≥ 20 mm. ACI 7. 3. 15 mm or diameter of bar. Unit weight for feet per metre = (D2/ 533). Spacing of bars = 180 mm c/c < 300 mm and 3d ok Distribution steel =. 4H to 0. 1 - 10mm Ø vert. design wheel load. The slab is. 1 QA Stockist’s certification of steel reinforcing bars 25 4. is more that the diameters used here. 1 or the bottom bars required by 8. 2—Minimum flexural reinforcement in prestressed slabs 8. Weight of Main Bar = (102/163) x 126. 2—Flexural reinforcement spacing 8. Spacing of bar = area of a bar * width of strip / area of reinforcement required = 78. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. where. 25. 40 mm or diameter of bar whichever is more 2. Design of the footing cantilever slab portion (per meter strip) Note that the bending moment in the slab is maximum. The transverse bar must be No. FAQ . It brings economy to the design of. 667’ x 40. spacing of 18” d) Choose bars: For square footings use the same size and number of bars uniformly spaced in each direction (ACI 13. Important Point: As per IS 456:2000, the limit on minimum reinforcement along either direction has been specified. slab should not exceed three times the effective depth of the slab or 450 mm whichever is smaller. The code itself suggests that the diameters can be #3, #4 and #5. 2 mm. spacing in plates and two-way slabs with concrete covers. The diameter of the chair bar should not be less than 12 mm. however we need to understand the requirement of chair. The maximum spacing of bars shall not exceed. Minimum S&T reinforcement quantities required by ACI 350-01 and11. 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. 2 m), regardless of steel grade. c. 6. Modify ACI 318 Sections 17. 1. 5% steel (continually reinforced) as described in Section 8. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. 4 bar at the top and the bottom. VARIATION AMONG BETWEEN MAIN BARS AND DISTRIBUTION BARS: 1. 2. The manual design process included the reinforcement calculation for the main. The spacing of the lateral ties is 100mm to 200mm for safe structure design. 2 or 8. 6. 24 SOLID SLABS 24. The dowel bars are provided in the direction of. Now, we will calculate the length of the three parts of the chair bar separately. 4. 4 Minimum Eccentricity Step 5: Calculation of Steel Weight. 5—Application of the simplified method 3. 5 mm 2. = 2sqm/1sqm = 2nos. For example, for 12mm. Wall Load Per Running Meter. Assume diameter of bars and calculate spacing of bars. AS3600-2009 P P Lsy. 1. 7. TWO WAY SLAB DESIGN SPREADSHEET:Fig 10: Reinforcement of a slab. The spacing between longitudinal reinforcement of the column should be the greatest of the following: 4 cm; 1. Self-weight of the slab = 3. (14) Step Find the load transfer capacities , , and of single dowel bar with the. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. of Main bars = (Width of Slab/Spacing) + 1. Whichever is smaller,. 2. , 1-hr. 230m. This spacing should be reduced by a factor of 0. The clear cover is 30 mm ( top to bottom ) and the thickness of the slab is 150 mm. bars in two-way slabs. 7. for. 3) or the distance of centre of gravity of the concentrated load from the nearer support (ci.