14 x r x r) = 3. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. So, provide spacing of. normally lower dia rebar tends to more sagging while placing in top layer. Figure-2: Distribution or shrinkage and Temperature Reinforcement Bars in One-way Concrete Slab. 5. Note that required A s must be furnished in each direction. Distribution Bar. Chapter 9 which is also per mitted per ACI 349-06 Appendix D. 00mm Maximum Bar Spacing : 250. The slab is not. 0m from the fixed end. No of Bars/m 2 = Factored Load / Pcr. Length of the Slab = 5 m = 5000 mm. 4 Splices in reinforcement. 3. 6. The maximum clear spacing between parallel bars shall not be more than 1 N-6O. 18D sq. 1. The bigger span in the above slab, 5000, divided by the shorter span, 2000, is 2. 2. 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. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. They ensure that the load is not concentrated in one area, which could cause cracking or failure. Number of Main Bars = (Length of Longer Side / Spacing) + 1 = (6000/150)+1. 12. 12% of the gross cross-sectional area if HYSD bars (Fe 415) are used. (b) 18 in. Bar schedule for Slab; Table 3 : Bar schedule for SlabArea of single bar = (3. For the cranked bars near the supports at the top of the slab distribution bars of same size and same spacing are provided below the top bars. This is needed both to prevent splitting of the con-crete adjacent to the stud and to allow load to spread out across the width of the slab. 67’ Weight of Distribution Bars = d 2 /52. Distribution Reinforcement for Stairs. 4 bars in the middle third of the footing depth. 751. For rectangular footings bars in long direction should be uniformly spaced. 20 square inch (129 mm 2) in cross-sectional area shall be provided: 1. 12 x 100cm x D cm=0. No Of Bars Required For Cutting Distribution Bars. 1 given below by the ACI 318-14 code. with 12mm. 15% of the total cross-sectional area of the slab (bD). The minimum percentage of reinforcement is 0. Distribution bars are provided in the longer span direction. The length of a distribution bar in west side is the same as the east side. The dowel bars are provided in the direction of. 0m from the fixed end. 1. the quality and basic shape of reinforcement bar shall be specified. slab, shall not. 0014: (a) Slabs where Grade 40 or 50 deformed bars are used: 0. 6. 9. What Is Bar Bending Schedule | Preparation as Per Bs 4466 | Tolerances as Per Bs 4466; Disadvantages of Dowel Bar. Note: The minimum clear spacing of bars is not kept less than 75 mm (Preferably 100 mm) though code do not recommend any value. Design size and spacing of dowel bars at an expansion joint of concrete pavement of thickness 20 cm. 1. It is a two way slab. 376Kgs For Floor slab -2 (One way slab) :-As per the above figure Floor slab -2 is a One way slab. 0018. 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. 12, apply only to one-way slabs (all code sections cited hereinafter are from ACI 318-08): “7. Number of bar =radius of slab/spacing. The diameter of the main bar is 12 mm in diameter with 100 mm c/c spacing and the diameter of the distribution bar is 8 mm with 130mm c/c spacing. 26. Modify ACI 318 Sections 17. 5. The design of one-way slab is simple and can be carried out easily. × c/c distance between the top distribution bar) + (extra length on either side of the top distribution bar)]Calculate the nos’ of facet rebar. Calculate cutting length: calculate the required number of bars for both directions. 4. 1. 091 = 300. 5. 1. 12: Reinforcement detail in continuous slab 3. TWO WAY SLAB DESIGN SPREADSHEET:Fig 10: Reinforcement of a slab. 3 Slenderness Limits for Columns 25. 12. and the clear spacing between the bottom bars a = 60 mm. 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. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 002 times the gross cross-sectional area of the footing. This type of reinforcement is convenient for modeling layers of reinforcement over a portion or the entire slab area. 1. 3 – When spacing of tendons exceeds 54 in. 7. Sub-Grade and. properly jointed slab. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs. joint spacing greater than 50 ft (15. 7. 12. 1. 318-081, Section 7. 1—Minimum flexural reinforcement in nonprestressed slabs 8. (i) The pitch of the main tensile bars in R. Distribution bars placed on top of the main bar. 6 Live Load. For 8 mm diameter bar 7 inches to 9 inches center to center c/c. 960m. 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. 1 Cement 5. Eurocode 2 section 9. For ACI 318-08 and ACI 318-11 5. For example, for 12mm. Step 2 – Calculation of Cutting Length. , 0. 11*12 in c/c Step 6 : Temperature and Shrinkage ReinforcementWeight of distribution of 8 mm dia steel bar = 33. About this chapter: Chapter 3 covers general regulations for plumbing installations. 1—General 8. 6 = 17. 6% of the gross wall area for Grade 60 or Grade 40 bars, respectively. 2 Maximum Distance between Bars in Tension. How to calculate bar Bending Schedule for Slab? One way slab Reinforcement Detailing. Sketch the detail of reinforcement. 11. Maximum spacing: The maximum spacing of main bars is limited to 3d or 300 mm (whichever. 25 x 87 =34. 5. 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. 3. Alternative reinforcing bar sizes and spacings having an equivalent cross-sectional area of reinforcement per lineal foot of wall shall be permitted provided the spacing of the reinforcement does not exceed 72 inches in Seismic Design Categories A, B and C, and 48 inches in Seismic Design Categories D 0, D 1 and D 2. For interior Spans: According to the code, the moments can be distributed according to factores shown in the figure: II. 4 Deck Overhangs for guidance on deck slab bars. 3. Unit weight for feet per metre = (D2/ 533). spacing of 18” d) Choose bars: For square footings use the same size and number of bars uniformly spaced in each direction (ACI 13. 25 8 #5 12 6 6 2 4. If shear reinforcement is required for in-plane strength, s shall not exceed the smallest of 3h, 18 in. 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. 12% Gross area for HYSD bars, 0. Bars shall not be smaller than No. Basically slab is the horizontal member which is rests on the beam section. stationary live loads less than 400 po unds per square foot. • 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. 10. Only 2. purchase orders, drawings, or per diems shall be done at the risk of those making such references or quotation. 7. W = 3. Compute number of steel bars. 4 bar at the top and the bottom of the footing or one No. 1. As always, local service records are the best guide for determining trans verse joint. Spacing of Main reinforcement bars = s m = 150mm c/c. Now. 5. 16. Weight of Distribution Bar for Waist Slab. 2. Main Reinforcement bars are placed in shorter direction and Distribution bars placed in longer span direction. 1 Spacing s of longitudinal bars in cast-in-place walls shall not exceed the lesser of 3h and 18 inches. • The. Distribution Bar = 1800 -2 (75) ÷ 150 +1. Step 2: Calculate cutting length of main bars and distribution bars. 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. That is 11′. The flow rate, Q, in gallons per minute, can be computed as follows: Q (gpm) = 0. 8 say 16 nos. , 300 mm. rahuledu said: as per IS 456:2000, chair shall be fixed 1 no in 1 Sq. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. 7. The thickness of Slab – 150 mm. 4. Number of bar =radius /spacing. vapor retarders - some times referred to as vapor barriers, insulation, etc. k’ = 0. 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. 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. 17 x 10 6 )/ (1000 x 119 2 x 25) = 0. spacing in plates and two-way slabs with concrete covers. 15m. MOM-X – Longitudinal moment, corresponding to which LONG. in. 304. Given Data: Height of footing = 600 mm. The spacing shall be less than five times the slab’s adequate depth, or 450 mm in the distribution bars. The punching shear capacity is obtained via the ACI code equations, seen below. 8. FIrst, find number of rods required for main reinforcement and distribution. Current recommended. Step 1 – Find out the Total Number of Main Bars & Distribution Bars. of main bars = Lx/Spacing + 1 = 5000/150 = 34. Since diameter of bar = 10 mm. 7. Total wt of Bars = 150. Weight of Distribution Bar=64/162. 1. advantage of the smaller lap lengths required for top slab bars. 12. 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. 2). 33=16 no’s. L 1 = (2 x spacing of distribution bar) + (2 x the clear cover). Clear cover = 25mm (top and bottom ) Thickness = 150mm. 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. 2. 4. Thus, there are three relevant issues: 1) According to ACI 318-19 Section 7. Common rebar sizes range from #3 to #6 for slab footings, with #4 being the most commonly used. Bar Spacing. Number of bar = 2150/150+1= 15. The minimum yield stress of main reinforcement bars and shear links in the structural elements forming the SS, S/C SS or scissor S/C SS or NS shall be minimum 500 N/mm2. C. 2R-8 4. 9) Check for shear ( using Table 19 of code IS 456:2000). Important Point: As per IS 456:2000, the limit on minimum reinforcement along either direction has been specified. So may be in this case, chair may be required more. 3. To firmly hold the main bars in their. ( IS: 456-2000 ). 6. bar per intersection 10mm Ø vert. e. 6 Reinforcement 5. The cross‐sectional area of one N28 bar is As = 620 mm2 and with N12 stirrups at 150 mm centres, Atr = 110 mm2. 0 8 #5 12 6 5 2 4. 6. Distribution bars are placed on the top of the. Suppose we have a one way slab,which having a length 5 m or width 2 m (clear span). 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. f ck = 25 Mpa. and floor finishes 1 KN per meter square. 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. 54 * 1000 / 180 = 436. Calculation of number of distribution bars. It brings economy to the design of. ACI 7. Ex. 2 and 26. 14 x r x r) = 3. Design of slab. 26. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. Spacing =80mm. slabs) or. Provided to resist the shear stress and cracks. A diagonal crack that might result in shear failure, as suggested in Fig. 4. 230/0. 3. 10. 5 times effective depth d. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. Each alternate bar is cranked up to 0. 2 Symbols Relating to Shape of the Bar Along Its Length As per IS 456: 2000, Cl. 3. For a 6 in. 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. , 450 mm. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. Type and spacing of the control and construction joints. Where a slab on ground is cast monolithically with the footing, one No. critical section of the slab is just outside the outside edge of the beam supporting the slab. 21Two-Way Slabs 6 b- Distribution of the total factored static moment to negative and positive moments: I. 13. 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. Design procedure. Spacing of bars = 180 mm c/c < 300 mm and 3d ok Distribution steel =. R403. There are no SHGC requirements in the Marine Zone. 1. “D” bars (Distribution bars) - Longitudinal bars in the bottom mat of deck reinforcement. In case of mild steel, minimum reinforcement along either direction shall not be less than 0. 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. Spacing s of longitudinal bars in precast walls shall not exceed the lesser of (a) and (b): (a) 5h. , and ℓw/3. it's a tool to maintain the spacing between two separate layers of slabs, footing etc. 6—Factors affecting the construction load distribution 3. 2) For main bars, maximum spacing is restricted to 3 times effective depth or 300. 3. Main Bar = 12 mm, Spacing – 150 mm c/c, Alternate bent up. (14) Step Find the load transfer capacities , , and of single dowel bar with the. Weight of Distribution Bar= (8)²/162. STEP. 1 given below. The minimum percentage of reinforcement is 0. Design size and spacing of dowel bars at an expansion joint of concrete pavement of thickness 20 cm. 8. Unit weight of concrete = 25 kN/m 3. There are also new provisions for integrity reinforcement. Number of Distribution. Main Bar. 5 m). Dual degree in Civil Engineering, and M. The clear cover will be 25 mm(Top or Bottom) and the thickness of the slab is 150 mm. 12. 5 inches (Singh & Saini, 2019). 4. 4. >EAST side. EXAMPLE: Suppose we have a one-way slab, which has a length of 5 m or a width of 2 m (clear span). 5% or 0. • Maximum area of main steel in slab = 4% 𝑜𝑓 𝑏𝐷 (As per ACI). e. Lesser dimension bars are used. e. Also useful for attaching stirrup bar effectively. Max BM = wl 2 /8 = (14. where. 4 Water 5. Mainly used in slab and footing, it is the most significant part of raft foundation. S. Bar Spacing. 2—Construction load factorsThe diameter of the main bar should not be less than 8mm for the HYSD bar and 10mm for plain bars. For distribution bars (cl. Given the radius of relative stiffness of 90 cm. 3. No. 305. 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. 93 m 2 ) = 469. 40 cm;. The code itself suggests that the diameters can be #3, #4 and #5. spacing of bars should not be more than. In this article I will explain you complete slab design as per IS 456 code by using manual method. Concrete cover to main reinforcing bars shall be provided per AASHTO Table 5. 200= 6. 5. The length of a distribution bar in east side is, = (17′-1½″) + 2 × 10″ = 18. 2Dead Load + 1. exposed to earth or weather. 6. Figure 3. A beam is similar to a slab in so many ways but there are fundamental differences in behaviour and stress distribution of the two. The ideal spacing for these bars is around 18 to 24 inches on center (from the center of one bar to the center of the next), depending on the expected loads and local building codes. 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. This is also. Width of the Slab = 2 m = 2000 mm. 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. bars in two-way slabs. Minimum number of bars. 2, The diameter of reinforcing bars shall not exceed one-eighth of the total thickness of the slab. 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. Height of block wall = 2. 5, the lateral spacing of the flexural bars should not exceed three times the thickness of 18 inches. Refer to Section 5. f. where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. The maximum anchor nominal diameter is 5 / 8 inch (16 mm). 1 of IS 456:2000, the reinforcement in either direction ,in slabs shall not be less than 0. 6. 2. 2. 2, or >0. The slab is supported all around walls of width 300 mm. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. Ensure a minimum number of bars in a square column is 4 and in a circular column, 6. spacing of bar/prestressing strand etc. unless otherwise noted in plans or specifications, camber all r. 13. Lapping is not allowed for the bars having diameters more than 36 mm. 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. 8. 15 % of the gross area if a mild steel bar is used. Wood structural panels with a minimum thickness of 7 / 16 inch (11. Bar crank. 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 ). Main Bars and Distribution Bars in Slab and Their Function. 3 ANALYSIS 3. Reinforce concrete for a 5-inch thick concrete slab: For a 5-inch thick slab, #4 (1/2-inch diameter) rebar is commonly used. 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. 9 Factored loads Factored dead load = 3. M o can be distributed, according to factors given in the table 8. where is the radius of the wheel load distribution in cm and is the slab thickness in cm. 1) The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 3. Slab steel bar spacing maximum 150mm c/c. 12.