or >) The minimum floor thickness shall be 6 inches. 4 bars. Build the wall full height, place concrete continuously in 4-foot lifts, and consolidate each lift. #IScodes #Concrete #Concretetechnology Recent & Related Videos Concrete. Ilang Araw Ang Pagbuhos Ng Simento? In this video, I'm sharing you the process of concrete pouring and sizes/spacing of rebars for the beams and slab concrete for the. For the trapezoidal, dovetail, and reentrant composite slabs, and RC slab, welded rebar meshes with Φ 8 ribbed bars were selected, and bar spacing was 200 mm in both directions. 5, which correspond to diameters of 3/8-inch, 1/2-inch, and 5/8-inch, respectively. . For Greece, the maximum aggregate grains dimension for usual concrete, is 32 mm and for self-compacting. . 2. Placing the rebar at the bottom of the slab will provide no benefit to the concrete. When two slabs are moved together, the impact loading created by the slab is reduced. 5 meters and the support beams are basically 18 x 18 inch reinforced concrete beams that are really strong. . cedures used to design and construct slab-on-grade such as streets, highways, and floors. 9836 m 2 Area of openings (lift and staircase) = 18. For columns and beams, the minimum spacing should be 6 inches. 00 m 7 cantilever reinforced concrete beams 18 mm for every 3. I'd use: 8" thick concrete wall with #6 rebar at 12" oc EACH WAY with the VERTICAL rebar placed 3/4" clear from the face of the INTERIOR BASEMENT ROOM. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the. 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. For flat slabs like driveways and patios, spacing is roughly 18″ to 24″. Because of this, the Building Code places limitations on the size and spacing of rebar in gunite & shotcrete. 2 (ACI 318-11 Section 13. 5 try 100 mm Dead load Slab weight = 2. Y. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. Next fill the cores with grout and repeat the process--lay another 4-foot. 375 inches, which is equivalent to 9. 3%. It is not hurting anything by putting it in a floor slab, but unless it is in the bottom third of the slab, it is providing zero strength, just keeping the pieces together if it cracks. You can use the concrete Rebar calculations to find the amount of. If the slab is poured against an existing foundation wall or another slab, you would use the #4 or #5 rebar to dowel it to the which ever you are butting too. My understanding of slabs based on limited experience and a heck of a lot of reading here is:1. f. 24-foot joint spacing. 7Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1805. Subject: Re: Rebar in shop floor? Kingston,Mi. 3 Storey Building: Larger diameter rebars, such as 16mm and 20mm, may be used to accommodate the. However, there is no need to tie the garage slab to the new foundation, and in fact a strong case against doing so. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. 30% carbon cont ent and only. Where, d is the diameter of the bar. 2: Repeat and continue to draw complete (closed) shape. For driveways and patios, #4 (1/2 inch diameter) rebar is a common. In either case, blocks should be used under the reinforcement to keep centered. Besana. 3, No. 2130605 2 = second floor B = beam member 06 = 6/8- or 3/4-inch (1. Note: Cut the two side form boards 3 in. These new concrete slabs do not account for second floor installations or installations in a ground floor with a basement beneath. I am confused about the grid. AS3600-2009 P P Lsy. longer than the length of the slab. If the pressure on the concrete is to come from the top of the slab, the reinforcement should be laid deep near the bottom of the slab. ( W) Width of the slab. If Steel grade 60 is to be used, the minimum slab thickness is taken as L/20 where L is the span of slab. #4 is 4/8”, or 1/2”. 00 m shorter span one-way floor slabs under 3. For M15 concrete, lever arm = 0. #Lonbicooltv Using the search function should turn up a lot of info. 2—Slabs-on-ground 5. 4 bars in the middle third of the footing depth. What size rebar do I need for a 6 inch slab? The size of rebar needed for a 6 inch slab would depend on the specific application and requirements. Where the bar used is Grade 60 and the size specified in the table, the actual spacing in the wall shall not exceed a whole-number multiple of 12 inches (i. Map rebar and rebar patterns. The numbers range from #3 (smallest) to #18 (largest). Fabrication of rebars consists of cutting to length and required bending. 11 in. 5. Ridges in the surface of the rebar allow the concrete to adhere to it and create one solid structure. For this case, the lift should not be installed without. The national average cost of a concrete slab is $6. e. Pour 6" fiber reinforced concrete over it. Multiple layers of c r ossing bars cause these pro b - l e m s . T F 8. Cracking Unexpected cracking of concrete is a frequent cause of com-plaints. The fibers are overkill in my opinion. What Size Rebar for Concrete Slab? This usually depends on the intended workload. Why? While concrete is very strong in some ways, it also has a few. of main bars – One = [Lx ÷ bar. 96-8. Maximum spacing: The maximum spacing of main bars is limited to 3d or 300 mm (whichever is less). Provide the required spacing and diameter of the rebar. One Way Slab Bar Bending Schedule Calculation. Minimum aging of new concrete slab: 28 days (cure time) Minimum thickness of concrete slab: See new slab table & figures below. spacing requirements and to repeat bar size and spacing as often as possible. 2. 6 Pedestrian Circulation--Stairs and. The nominal building width should be calcu-lated as follows: 1. Wire mesh is better then rebar, if it can be kept up off the bottom of the slab. If you are trying to put a new concrete slab on your small-scale domestic project; 6mm (#19), 8mm (#25), and 10mm (#32) rebars will do the job nicely. Free Reinforcement Calculator. 1: Calculate The Main bars. And the rebar details of (1) is 10mmØ @ 8″ c/c. 3. 12mm. Rebar Grid Calculator. Reading time: 4 minutes. Enter the slab dimensions, desired rebar spacing and the spacing from the edge to quickly find how to lay out the rebar grid. If the floor is. MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES) b, c: Soil classes and later soil load d (psf per foot below grade) GW, GP, SW and SP soils 30: GM, GC, SM, SM-SC and ML soils 45:Concrete Floor Slabs On Grade Course# ST-702 EZ-pdh. 6: 20mm clear cover in slab is sufficient. in concrete slabs. The no. 2-inch slab and 3-inch chairs for a 5-inch slab. 74 sq feet 5000/2. #5 rebar on a 6X6 grid, No cracks in that, poured the same time as the slab in the heated addition. S. 3. To maintain strength and longevity, concrete slab rebar spacing must fit together like a jigsaw puzzle. This part has a reinforced concrete slab on the 1st floor(2nd floor for any american readers) with several walls built right up to the underside of the slab. Some brands of forms have preformed chases that run the length of each. Commonly called “rebar,” these 1/2-inch-diameter steel rods are embedded in the center of the slab to create a grid that extends lengthwise and crosswise to help the concrete better resist pulling and bending forces. For example, a slab that is 6 inches thick might have rebar marked as size 6 or 3/4-inch. 5 inches up to 12 inches. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by PTI, the tendons are stressed. Steel reinforcement bar size for footing of G+1/ 2nd floor building:- we will assume a structure of G+1 (two storey) residential building, using standard 4″ thick walls, according to general thumb rule, use of mesh bar of 12mm or number 4 (#4) size (diameter) of steel reinforcement as main and distribution bar (T12@6″C/C of Fe500) is most. 04 Required spacing, s = 242. A slab with this joint spacing may be reinforced with bars (ASTM A 615, A 616, A 617, or A 706) or WWF (ASTM A 185 or A 497). 3. , where a T-beam girder is supporting T-beams that in turn are supporting slabs, as shown in Figure 8. Drive a stake at the end. Ex. x 20 in. Guidance for joint spacing to minimize out-of-joint cracking for such slabs. Two-Way Concrete Floor Slab with Beams Design and Detailing . Often, concrete contractors don’t have solid runs of rebar anyway. 4m x. FIrst, find number of rods required for main reinforcement and distribution. In this video, you will learn the Spacing between the Main and Distribution steel bar. -Multishearing. 00 m 14 over 6. 8 ). If your two slabs have different spacing for their rebar mats, measure and mark so your dowels fall in the middle of the spacing of the second slab. 18 bar 11/2″. There are many variables that influence the decision of how much space to leave, including the maximum load the slab is likely to have to support, the bearing capacity of the soil, the diameter of the reinforcing rebar, the likelihood of frost heaving the. 00 m 7. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /5. STRENGTH REINFORCEMENT REBAR SPACING GP‐7 SERIES MODELS 4‐1/4” 3000 PSI / 28 Day Aging #6 Rebar 12 In. (i) The maximum spacing between two parallel main reinforcing bars shall be 3dor 300mm or whichever is less, and. Level, straighten and brace the second form board. The result is a lightly reinforced slab designed to offset the effects of temperature and shrinkage of the concrete. This type of slab is used on the Basement floor. ) slabs are plate elements used to form the floors of buildings. 1) for con-c r ete cover over re i n f o rc e m e n t h a v e not been consistent. This new slab design does not account for second floor installations or installations in a ground floor with a basement beneath. Methods used for finding slab thickness varies for different types of slabs. SLAB MIN. When concrete is first mixed and poured, it has excess water in it and in the hardening process, the concrete loses its excess water which causes shrinkage cracks. For this case, the lift should not be installed without written authorization from the building. * BEAMS SHEAR CONNECTORS (IF PRESENT) For M15 concrete, lever arm = 0. Avoid using air contents over 3% for interior slabs. Check the Buckling Capacity of Rebar. , edge beam dimensions = 14 in. The top of the wall will need "hooks" in the rebar in order to fasten the wall to the garage slab. According to Indian standard rcc concrete roof slab thickness in residential building construction is 4 inches (100mm). Clear span of the two way slab = 5000 mm. Multiple layers of c r ossing bars cause these pro b - l e m s . 73 per square foot for concrete installation. 2. I am pouring a slab for radiant heat next week and I have been given a variety of advice on whether or not to use rebar. Figure 1a: Joint Spacing in Meters. Summarize and show schedule of the design outputs such as beam dimensions, main rebars diameter and quantity, and shear rebar diameter and spacing. 12% for HYSD bars and 0. com Round Measurements To Running Bar Points (Length - Left to Right): Running Bar Points (Width - Top to Bottom): Calculate Rebar Quantity From Total Slab Area and Perimeter To calculate Total Area of a multi sided slab, first divide the shape into rectangles or squares. , or 5 h, where h is the slab thickness. 6. You will be able to add radiant floor heat any time. The two design options are a ground-bearing slab, or a pile supported suspended slab. 60 per square foot. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. Divide your result by the spacing measurement: 180 in / 14 in = 12. 14 and No. First, it avoids that the column transmits to the slab a concentrated force, which would cause large stresses in the concrete slab and likely large damage. NOTE: Section 1907. Shrinkage cracks are probably the most common type of cracks in concrete. Expansion grooves should be cut into the wet concrete to provide additional crack resistance. Tie pieces together with rebar ties. The specified compressive strength of concrete shall be as set forth in Section R402. Tie the rebar together. In t e r p r etations of the ACI 318 code re q u i r ements (Ref. This is for a building with 1st floor SOG, 2nd floor slab, 3rd floor transfer slab and wood framing above. There are three different sizes of rebar typically used for home construction projects. SCI P300 is a comprehensive guide for the design and construction of composite slabs and beams using steel decking. 1R and 421. 5/16" 2" long bolts thru tight holes spaced 3" apart at the outer ends and then increasespacing by 1/2. ICF Foundation and One ICF Story – The sequencing here is to build the foundation walls first, place concrete, and then build the above-grade walls second. x 27 in. Rebar should be placed evenly throughout the project. For the purpose of analysis and design, a unit of the slab is cut out at right angles to the supporting beams, shown in Figure-2, which may be considered as a rectangular beam. So, if we have used 12mm dia rebar in column maximum permissible spacing is 72mm and for 16mm dia longitudinal rebar the spacing is 96mm and so on. Sudip Shrestha. a core down to the top of the rebar would confirm its size. Minimum spacing between reinforcement bars in foundation tie-beams Concrete casting in foundation tie-beams is not an easy procedure. SLAB ON GROUND—A type of foundation with a concrete floor which is placed directly on the soil. ( LF) Lapping Factor. Rebar being #4 grade 60. c) Slab reinforcement percentage less than 0. Floor Under Solids or Semi- solids and Single Axle load (15,000 lbs. Rebar spacing calculator is perfect to indicate how much Rebar is needed. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808. Floors shall be a minimum 3 1 / 2 inches (89 mm) thick (for expansive soils, see Section R403. The steel rods help reinforce the strength of the concrete slabs giving the structure a strong form. Figure 5. The #3 rebar has a weight per length of 0. The load needs, and the span of the slab decide the spacing, size, and placement of the bars. , and unfactored live load = 100 psf. a) Slab depth does not exceed 250mm when the steel grade is 250. A flat plate floor with a live load of 100 psf is only about 8% more expensive than one with a live load of 50 psf, primarily due to the minimum thick-ness requirements for. ACI 360, "Design of Slabs-on-Grade", refers to this as a Type B slab. Use of 5″ to 6″ (125mm to 150mm) is recommended if the concrete will receive occasional heavy loads. There's no generally-accepted rule of thumb as to how to space rebar in a concrete slab. Input all the dimensions in the input section of the above calculator. Concrete slabs-on-ground containing 6 × 6 W1. girder sides & slab on grade - 1 reinforced concrete beams 6 mm for every 4. This how-to guide will show you how a. Figure 1. 00 m span 3. The provision of adequate reinforcement, slab thickness, and. x 18 in. Minimum thickness of concrete slab, beam, column, foundation and other structural members is selected to meet the design requirements as per standard codes. It illustrates and explain. The minimum size and grade of rebar for slabs depends on a variety of factors, such as the thickness of the slab, the loads it supports, seismic requirements and other factors. In this video i will show you about 2nd Floor Slab Rebar. 4 × W1. The installation of the rebar is critical for the success of the overall project. Corner angle. The typical depth for rebar placement for slabs is 2-4 inches. 5 to 7. (150 to 250 mm). The bracing comes out after curing. To be memb. In the Philippines, buildings face various environmental challenges such as strong typhoons, earthquakes, and floods. -l. square columns and concrete block wall supporting 10in beams @ 12ft on centers front to back. Dynamic and/or oscillatory. Steel fibers, at 1. For footings that are poured before the slab, two #4 horizontal pieces of rebar are required – one 3” from the top and the other 3” from the bottom. See full list on everything-about-concrete. Inclined length = 0. It create a bending of the slab. Dig a min of 24 inch deep by 36 inch square footing below the point of connection to the equipment above the slab. However, no matter how basic or complex. less than around 0. No, you do not need rebar for a 4-inch slab of concrete on grade. For example, if a 6-inch-thick slab is used with #3 rebar at 18 inches on center, the percentage of steel for a 12-inch width would be: (0. To define design strip rules, click the Slab Design Rules button on the Data Entry toolbar. 45 to 1. 00 m span 3. This is one of the types of concrete slabs. Two layers of steel bar reinforcement are needed for secondary containment floors because tank loads induce both positive and negative bending moments in the floor. 6mm. The performance of the paving joint is enhanced by these bars. I am filling a 12 ft x 12 ft sunken lounge are with 12" of Geofoam as filler and a 4" concrete slab. Much of the time, the depth that finishers install control joints is less than what is normally recommended. The basic building block of this application is further known as a composite floor slab. 2L at the intermediate support. My main building is 6" concrete with #4 rebar on a 6X6 grid. This configuration directs load transfer predominantly in a single direction toward the columns. If the concrete slab in question is meant to be the footing of a house, then #5 rebar with a. Number of Required Bars Formula = (Length of slab / spacing) + 1. Rebar in patios, basement floors, footings and driveways may vary from size 3 to 6. By: Olin Wade (Remodel or Move Stuff) The spacing of rebar in a slab depends on the purpose and size of the slab, as well as the climate in which it is being built. The spacing of the main steel in a slab should not exceed the following:First, the American Concrete Institute (ACI) Residential Code Requirements for Structural Concrete (ACI 332-14) requires contraction joints and provides a table to determine joint spacing for plain and reinforced concrete containing up to 0. For example, one-way slab thickness. reinforcement for the bottom fibers of the composite slab. Unless you are going to park a very large truck on the slab the 2'x2' oc #4 rebar is over kill IMHO. Clause 6. slab opening det. For example, at Column I-4 between the basement and first floor, building plans required four pieces of horizontal rebar through the column in both directions to connect it to the slab. Here:Bar Tying Requirements. rebar strength is in tension, so by adding rebar to BOTTOM of foundation, it counter acts the load of compression. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. Contact*: Severity*: Description*:Problem #3 – Shrinkage cracks that allow moisture to reach the rebar. Rebar SizesOn studying the drawing, Length of longer side of building = 16. b. a) Slab depth does not exceed 250mm when the steel grade is 250. For the rebar-truss composite slab, the top chords, bottom chords, and web bars were Φ 10 ribbed bars, Φ 8 ribbed bars, and Φ 4. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. The maximum size of reinforcement shall be No. It create a bending of the slab. 5 bar or two No. REBAR SPACING: GP‐7 SERIES MODELS: 4‐1/ 4" 3000 PSI / 28 Day Aging #6 Rebar: 12 in: XPR‐9 SERIES MODELS: 4‐1/ 4" 3000 PSI / 28 Day Aging #6 Rebar:. 600-2 DETERMINATION OF BUILDING WIDTH A. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. 1: Calculate The Main bars. 73 Therefore, use 12 mm bars @ 0. The evaluation of rebar spacing results shows that the maximum standard deviation for rebar spacing is 0. There are two types of Grade slabs: Usually after casting Plinth beams. Functions of Distribution Bars In A SLAB: Distribution bar is to provide at the long span of the slab. 1 of the 2021 International Building Code (IBC) specifies that the thickness of concrete floor slabs supported directly on the ground shall not be less than 3 1/2″. The minimum Sub-Base thickness shall be as shown in the table. (ii) The maximum spacing between two secondary parallel bars shall be 5dor 450 mm or. 3. On average are required, for 10 square meter with 12cm thick slab, 19 strips of 3/8” rods (9ml each one), are 171 ml. SLAB—Flat section of floor or roof either on the ground or supported by beams or walls. The compaction UNDER the slab is more important than the thickness of the slab. The gauge, or diameter, of the rebar is selected based on the purpose and the load-bearing requirements of the structure: For standard residential concrete slabs, #3 (3/8 inch diameter) to #5 (5/8 inch diameter) rebar is typically used. 5" 3,000 PSI / 28 Day Aging. The maximum size of reinforcement shall be No. L is the effective length of the beam and slab. You cut as 4,000mm +760mm = 4,760mm. 2ND FLOOR CRACKING WIDTH. The actual measured building width must be converted into the nominal building width for use in the Foundation De-sign Footing Tables and Anchorage Tables. This guide is not a standard nor a specification, and it is not intended to be included by refer-ence in construction contract documents; ACI 330. Normally, it is assumedchanges in deck slabs, and sloped slabs over beams. Total Weight of rebar in pounds. 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. If the weight of each steel beam is 62 lb/ft, determine the dead load in lb/ft supported by any interior beam. 9 cm)-round bar 05 = part of second floor plan designated by the number 5. Design of Two-way Slabs: Slabs are defined as two-way slabs when the ratio of long-to-short sides is less than 2. D bar or 10 mm if you are using Plain bars. rebar strength is in tension, so by adding rebar to BOTTOM of foundation, it counter acts the load of compression. Annex. Matthew Stuart, P. Patio slabs are used in pathways. ACPA Guide Specification | Dowel Bars for Concrete Street and Highway Pavement | ACPA M254-21 April 8, 2021 | Page 4 of 11 CSA-Z245. 5 round bars, respectively, while. 1 shows the design detail for a secondary containment floor slab with two layers of reinforcing. for 500 MPa reinforcement it must be either 500PLUS® Rebar (Class N) or OneMesh500™ (Class L). 3: Two-way slabs supported on four sides; Clause 6. 9mm deformed rebar for walls instead of 10mm. or slab change soffit typical detail for beam 400 dowel 250 300 (typ. dustrial floor slab. In some cases, concrete needs reinforcement with steel mesh. ACI 332, Section 10. 15. 2-25. Prior to the placement of reinforcement for concrete floor slab construction, inspect and check forms to confirm that the dimensions and the location of the concrete members conform to the structural plans. Added to that, the forms shall be properly cleaned and oiled but not in such amount as to run. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Unit 571 New Smyrna Beach, FL 32128 386-882-EZCE(3923). Stainless steel rebar. 5-3 Dowel size and spacing. This new slab design does not account for second floor installations or installations in a. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. ACI 318-14. . Rebar is tied together, using wire, to hold it in place. 1. Grade 40 means that the yield strength is 40,000 psi and the code allowed strength is 20,000 psi. C. • Basement floor slabs with integral footings must provide for 5000 psi concrete in that portion of the slab acting as a footing. Fo r decades ACI 318 has re q u i r ed high-Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of ACI 332 and this section. We can also pinpoint the depth of every object we locate in concrete with an accuracy of +/- 10-15%. 2. unless otherwise noted in plans or specifications, camber all r. 1(a)(5) of ACI 318-19 states that the size limitations on aggregates are provided to facilitate placement of concrete around the reinforcement without. 15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete floor slab, or other approved equivalent methods or materials shall be used to retard vapor transmission through the floor slab. We recommended to use 5″ rcc roof slab thickness 1, 2 and 3 storey building. )(100)/(6 in. 21 = 183. I have reinforced composite slabs 3 ways: all mesh (my least favorite), all #3 bars, or mesh w/ rebar over the beams only for slab negative reinforcement. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. 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. The minimum spacing between two reinforcement bars should be at least equal to the maximum coarse aggregate dimension plus a margin of 5 mm. 3. 1. Rebar would be absolutely required in a footer located near the frost line or in the areas subject to moisture changes in shrink/swell soil areas. Expert Help. ) (12 in. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. 3 Factored live load = 3. However, if the concrete slab is meant to be the footing of a small structure, #4 rebar with a diameter of 1/2-inch should be used. 2R for suspended floors. You should still use reinforcement material, but there are other options besides rebar. Understanding the Importance of 2nd Floor Slab Thickness for Building Safety and Stability in the Philippines The safety and stability of a building depend on various factors, and one of the most crucial is the thickness of the second-floor slab. If you are trying to put a new concrete slab on your small-scale domestic project; 6mm (#19), 8mm (#25), and 10mm (#32) rebars will do the job nicely. 10. For general purpose concrete slabs with 2,500 pounds compression strength, like patios, use a 1:2:4 concrete mix ratio. 2. 5% of the cross sectional area of a slab. Essentially a early age concrete shrinkage problem (cement paste not reaching full strength/bond with aggregate and restraint on the concrete member due to rebar. vided in the slab under the net. This new slab design does not account for second floor installations or installations in a ground floor with a basement beneath. The Building Structural Standard defines a two-way slab system as a concrete slab system in which two rebars are arranged in two directions regardless of the presence or absence of a beam that transmits a load to. Make sure it is in the very center of the slab as if it is too close to the top or bottom it is also useless. To se-lect the appropriate steel area (As), use the For example, if both slabs have rebar mats that are spaced at 18 inches and use No. 2. Pour 6" fiber reinforced concrete over it. x 18 in. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. , F. 1. 1R-92 (Ref. 00 m 4 3. Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. ( W) Width of the slab. Total Volume of concrete in cubic yards.