150m = 150 mm. 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. slabs is Thickness of slab/8 14. 2), The bar spacing shall not exceed 450 mm at any location (ACI Code Section 7. 4 Deck Overhangs for guidance on deck slab bars. 347. where. If a closer spacing of bars is required at the columns, as per Section 13. 5. k < 0. 6. 5-2 Recommended spacing of transverse. for industrial slabs that carry distribution. Load Calculation: Live Load = 2 kN/m 2. design wheel load. First, find number of rods required for main reinforcement and distribution. 9. Step 1. 4. Total Cutting Length Of Rod = 2nos x 1. 6 𝑀𝑃𝑎. Check resistance to moment transfer from column to slab . 2Dead Load + 1. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. per 1 m 2. 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. 300mm. to carry a uniform live load of 7500 Pa. 54 * 1000 / 180 = 436. Sawcut Joints A typical SOG includes three different types of joints, described in detail in ACI 360R Chapter 5. For 8 mm diameter bar 7 inches to 9 inches center to center c/c. 7. For distribution bars the maximum spacing is specified as 5 times the effective depth or. e. f ck = 25 Mpa. 17 x 10 6 )/ (1000 x 119 2 x 25) = 0. This smaller amount of reinforcement0. Main bar = 12mm@150mm c/c. 5. 1 or the bottom bars required by 8. 667’ x 40. The thickness of Slab – 150 mm. Provided to resist the bending stress. Distributed reinforcement is a bar spacing applied over a polygon area. 3. Spacing = 150mm c/c as per given details = (2950/150) + 1 = 20. ,). Exceptions: 1. 2 (6) Beams: the maximum longitudinal spacing between shear assemblies s l,max; 9. 5, the lateral spacing of the. 3. Given data: Distribution bar dia. Dia of Distribution Bar=16mm. 1. 2 Minimum Slab Thickness 4-1 4. 3. . 1. 4. The max. 1 General 24. 5. About this chapter: Chapter 3 covers general regulations for plumbing installations. Step 1 – Find out the Total Number of Main Bars & Distribution Bars. Given the radius of relative stiffness of 90 cm. The new formulas are more complex and consider more parameters, such as bridge length and. spacing in plates and two-way slabs with concrete covers. length of. e. 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. Clear span of the two way slab = 5000 mm. C. >EAST side. Length of the Slab = 5 m = 5000 mm. of distribution bars = Ly/Spacing + 1 = 2000/150 +1 = 14. 6H to 0. Step 1- Calculation of Numbers of Bars. Design size and spacing of dowel bars at an expansion joint of concrete pavement of thickness 20 cm. 7. Distribution Bar = 12 Number of The Distribution Bar. 5 bar or two No. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /3. 1 or the bottom bars required by 8. is lapped with a lower bar of 20mm dia. Weight of the bar as per their length and. 8 ACI 318 , Section 17. The maximum anchor nominal diameter is 5 / 8 inch (16 mm). Additionally, the clear space between the transverse bars and lapped bars may not exceed 1. Spacing Requirements. Now. LL = 6. As discussed earlier, assume that the beam is reinforced with two layers of #11 reinforcement and clear spacing between layers = 1 in. 5. 3-Main bar Bottom Area Given data. Basically slab is the horizontal member which is rests on the beam section. t + DChair bars are used primarily on the slab and flooring. There are no SHGC requirements in the Marine Zone. Main Bar. 7. For basic building the 4 number of bars is sufficient as per code. Diameter of a chair bar should not be less than 12mm. Structural Design 1 - Design of Reinforced Concrete Structures REFERENCES/COURTESY 1) IS 456 : 2000 — Plain and reinforced concrete – Code of practice 2) S Unnikrishna pillai and. Refer to Section 5. Cranking is also used in two way slabs. These bars should be distributed as evenly as possible between the negative moment design sections, with one bar being placed at the inside of each bottom truss bar bend. 6. 5 times effective depth d. as indicated in the table. Since diameter of bar = 10 mm. As per IS 456: 2000, Cl. 2. Main Bars and Distribution Bars in Slab and Their Function. The depth of voided slabs could reduce the height of the structural system up to one foot per floor compared. This is plotted against the overall fire rating of the structure that is being designed. But even after that If d,provided < d,reqd, slab thickness is to be increased and check for deflection is to be satisfied. Design procedure. equal to ( C < 2. Distribution Bar = 1800 -2 (75) ÷ 150 +1. 75H for surcharged wall. 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. BS EN 1992-1-1 Annex 1 1. Important Points. 4 bar at the top and the bottom of the footing or one No. Sub-Grade and. (1:1. 25 kN/m 2. 2, 17. EXAMPLE PROBLEM 1. Distribution bars of diameter 12 mm and center to center spacing 150 mmm. 3(d) and 17. 15%of gross cross-sectional area if plain bars are used and 0. 091 = 300. 6 = 17 bars; The number of distribution. the quality and basic shape of reinforcement bar shall be specified. 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. It is mainly to prevent upward bending moment near the joint. 7. Type and spacing of the control and construction joints. rahuledu said: as per IS 456:2000, chair shall be fixed 1 no in 1 Sq. 2. 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. STEP. The distribution bars should be (2000- 2 x 25) /125 + 1. 2 Use Φ12 bar c/c 250mm 2. 21. 5. Always main bar use in shorter span. MOM-X – Longitudinal moment, corresponding to which LONG. 5db). the maximum spacing between two secondary parallel bars in case of RCC Slab shall be 5d or 450 mm or whichever is less. The flow rate, Q, in gallons per minute, can be computed as follows: Q (gpm) = 0. For Min Steel: 3d ——— Where. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 1 mm) and maximum panel span of 8 feet (2438 mm) shall be permitted for opening protection in buildings with a mean roof height of 33 feet (10 058 mm) or less that are classified as a Group R-3 or R-4 occupancy. 1-4. 2 Maximum Distance between Bars in Tension. It covers the general features of design, loads and load combinations, structural analysis, materials, fabrication, erection and maintenance. L 1 = (2 x spacing of distribution bar) + (2 x the clear cover). 26. R4405. 2. Temperature distribution due to heat of hydration and internal stresses caused by outside cooling in a free standing concrete block. 8. 6. 7. Mild reinforcing bars shall have minimum clear spacing of at least 2 in. Lapping is not allowed for the bars having diameters more than 36 mm. 18D sq. for. 6 For two‐way slabs, maximum spacing of bars shall not exceed two times the slab thickness h nor 450 mm. For Edge Spans : Static Mom. 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. 67’ Weight of Distribution Bars = d 2 /52. 19. Wood structural panels with a minimum thickness of 7 / 16 inch (11. 4H to 0. 2 – Spacing of tendons shall not exceed 6 feet. 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 ). 167, hence it is singly reinforced. Length of distribution bars = 6. No of Bars/m 2 = Factored Load / Pcr. 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. deck slab and diaphragms, spliced girder system, precast pre-tensioned open or closed. 2: Alternate method for showing two-way slab reinforcement reinforcing bars should be clearly scheduled on the drawings. 4, Chapter 10 ct = distance from the interior face of the column to the slab edge measured parallel to c1. 3. Assume 𝑓𝑐′ = 27. 4 Slabs Spanning in Two Directions at RightAngles 24. Main Reinforcement Bars are used to transfer the bending moment developed at the bottom of the slab. TRANS REINF - Reinforcement required along the transverse direction ( along local Y axis of the plates ). Given the radius of relative stiffness of 90 cm. where a is the radius of the wheel load distribution in cm and h is the slab thickness in cm. 1—Early-age concrete material strength development 4. The previous code that allowed up to Grade 520 was changed to Grade 550, and related regulations were modified. 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. Distribution Bar. 7. 6. 7. Maximum spacing of tension bars (all slabs) In accordance with clause 7. 8. 9. Breadth of Footing = Y = 1. Bar Spacing. Weight of Distribution Bar=64/162. 1. Weight of Distribution Bar= (8)²/162. 1—Minimum flexural reinforcement in nonprestressed slabs 8. 7. 5 Admixtures 5. 12. 090 square inches per foot of slab width, required each way. 12. 3. 2 or 8. 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. the value of the calculated k is far below the limiting k’ for slabs. ”Distribution bars are typically used in conjunction with main bars, and they are often spaced at regular intervals along the length of the main bar. The bigger span in the above slab, 5000, divided by the shorter span, 2000, is 2. 12. 6 Reinforcement 5. 3. For ACI 318-08 and ACI 318-11 5. Generally, a #4 (1/2″) diameter reinforcing bar with a minimum grade of 40 is used for standard residential slabs. 2 and 26. Whichever is smaller,. 5 m as per IRC. Diameter of the Main reinforcement bars = d m = 12mm. 5. 3. 15% of the total cross-sectional area of the slab (bD). 3 only and there is no need to perform specific checks on the bar spacings to control cracking. 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. What are the different functions of distribution bars in concrete . 6. 3. Reading time: 2 minutes. Check resistance to moment transfer from column to slab . 1. This change affects the calculation of minimum slab thickness for fy exceeding Grade 420. 5. 89m. 2) For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. Provided at the top of the slab. 4H to 0. For main bars, maximum spacing is restricted to 3 times effective depth or 300 mm whichever is smaller. 7. 667’ x 40. The Clear cover will be 25 mm (Top or Bottom) and the thickness of the slab will be 150 mm. 8. 2(5)In slabs constructed with lift-slab methods where it is impractical to pass the tendons required by 8. Minimum Bar SpacingAs per AASHTO LRFD, section 5. slabs) or integral with slab with depth greater of 2. 7. 1. 304. C. Figure 3. Step 1: – Calculate numbers of distribution rods. steel bars. , nonskewed) bridges only. Crack Control – when crack widths are not checked by calculations No Further Checked Required. 76 Slab designation: CS1 Check if one-way or two-way slab 1 Slab is one way since it is catilever slab Minimum slab thickness min t = 69. Check for Cracking. Concrete Slab Design ProcedureSteel reinforcements can be use, however with a maximum spacing of 4. 5. Total Length of Distribution Bars = 19. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. NOTE 3 - In co1 3. 8. 7. 5, the lateral spacing of the flexural bars should not exceed three times the thickness of 18 inches. 4 bar at the top and the bottom. 31 of IS456-2000, the span by depth ratio of two way slab is applicable for flat slabs and the values can be (l/d)modified by 0. Dowel bars are typically placed at the mid-depth of the slab and should be parallel to the pavement surface and parallel to the direction of travel. 2. Table 1. 5, which equals 51. Maximum spacing of main bar is restricted to 3 times effective depth or 300 mm whichever is less. 785 x 16^2 = 200. Workmanship and jobsite conditions. 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. Distribution Reinforcement bar: No of bars = total span/spacing = 2960 mm/200 mm = 15. 5. Area of Steel 'Ast req. 3. In this article I will explain you complete slab design as per IS 456 code by using manual method. 18% of gross sectional area (B×D), taking B= 1m width of slab and D= overall depth including cover, then minimum reinforcement will be = 0. 12. 6 𝑀𝑃𝑎. Distribution of Main Bars. Tayabji (1986) identified the following categories of dowelmillimetres and N represents the identification number of the bar/bars given consecutively. One Way Slab Reinforcement Detail. How to Design Concrete Structures to Eurocode 2 - Chapter 7 : Flat slabs and Figure 6. Hence, in the above given example spacing for 16 mm dia bar has been calculated, thus. So, provide spacing of distribution bar equal to. The. of chair bars = Area of structural reinforcement in sqm / chair bar per sqm. As per ACI -The drop thickness should not be less than 100mm or (Thickness of slab)/4. 0018 times the slab's gross area, but the maximum spacing of the bars differs. Height of the footing (Thickness) = h =0. 60 kN/m. 1 General== a 1 in direction of 11 • = a, in direction of 12 • angle between the axis of a strut and the bars in the i-th layer of reinforcement crossing that strut. vapor retarders - some times referred to as vapor barriers, insulation, etc. They ensure that the load is not concentrated in one area, which could cause cracking or failure. 10mm Ø hor. Minimum Reinforcement Ratio in Uniform Footing. 7. 6. 24. 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. What is the maximum spacing of a distribution reinforcement to be used in a one way slab as per IS 456? b. Conclusion. • The. 3. Minimum reinforcement is ensured in slab (in both directions) to take care of shrinkage, thermal movements and. bars at 400 mm o. Spacing of Main Reinforcement: The maximum spacing of bars shall not exceed. Spacing =150mm. 2. 12. 12% Gross area for HYSD bars, 0. Two-Way. 7 For temperature steel only, maximum spacing shall not exceed five times the slab thickness h nor 450. Spacing of Main reinforcement bars = s m = 150mm c/c. 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. 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. the constant value of 50. Top & bottom main bar dia. 1 of IS 456:2000, the reinforcement in either direction ,in slabs shall not be less than 0. 10mm Ø hor. 3. 1 of IS 456), the maximum spacing is the lesser of 3d and 300 mm i. 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. 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. 04𝑥1000 𝑆= = = 272. 715m long, and it is supporting a blockwork load at 1. 5 in Y-axis Distribution area 3. Slab steel bar spacing maximum 150mm c/c. 18/100× × 100× D = 0. For a 6 in. It brings economy to the design of. 5. 1 (2) states that, distribution should minimum 20% of the main reinforcement. A beam is similar to a slab in so many ways but there are fundamental differences in behaviour and stress distribution of the two. spacing of bar/prestressing strand etc. Thus, the requirement threshold of 125psi (0. Spacing: ACI Code 7. Actual variety of 1 sides rebar =Number of main bar – rebar of the middle. Base slab width b= 0. • Maximum area of main steel in slab = 4% 𝑜𝑓 𝑏𝐷 (As per ACI). 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. The term "standard hook" as used in this Code shall mean one of the following: (a) 180o. 7. where is the radius of the wheel load distribution in cm and is the slab thickness in cm. For longitudinal reinforcement in beams. The minimum and maximum spacing reinforcement in concrete structural members such as beams and slabs are required as per standard codes. 6—Factors affecting the construction load distribution 3. 5d = 5 * 130 = 650 mm. spacing of bars should not be more than. 00mm Bottom Footing Clear Cover (F, CL). Design a one-way slab having a simple span of 3 m. 7. Minimum Reinforcement Ratio in Slabs. Maximum spacing: The maximum spacing of main bars is limited to 3d or 300 mm (whichever. 7.