t + DWhen a concrete slab is stressed by the post-tensioning method, it means the steel is being tensioned and the concrete is being compressed. The installation of the rebar is critical for the success of the overall project. Most residential slabs contain reinforcement of less than. Design of Floor Slabs (fc' = 28 MPa, fy = 276 MPa) Common design parameters: 0. , edge beam dimensions = 14 in. Ordinarily, the rebar supplier details, fabricates, and delivers to the site, as required. ) is going to be 5'-6' for 4 ksi concrete anyways. MAX and #5 top placed at center of slab" I installed the #3 dowels 12" apart and 6" into the existing surrounding floor. 5” long, are typically dosed at the rate of 60-68 pounds per cubic yard. The commentary R26. In that case, a layer of rebar near the bottom or at. . . If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. 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. Clear span of the two way slab = 5000 mm. Minimum tensile strength of concrete: 4,000 PSI. It says that floor slabs were patent designs back in the 1920's. Its primary purpose is to increase the tensile strength of the concrete, helping it resist cracking and breaking. In summary the design procedures for beams and floor slabs are similar with the following differences: (a) Minimum steel. A typical installation uses 6-inch by 6-inch woven wire mesh, which is supported on rebar chairs so it is positioned near the center of the finished slab. the calculator will give you the default spacing values (for rebar – rebar it’s 40cm, and for edge – grid it’s 8cm). Figure 1b: Joint Spacing in Feet Contraction joints may be tooled into the concrete surface at the time of placement. (5) Concrete foundation stem walls that are formed by a thickened concrete slab edge as part of a slab on grade floor must be reinforced with one piece of No. 75 to 3. Running Bar Points (Length - Left to Right): Running Bar Points (Width - Top to Bottom): Calculate Rebar Quantity and Mesh From Total Slab Area and Perimeter. ACI 302. One Way Slab Bar Bending Schedule Calculation. 2nd. #Lonbicooltv Using the search function should turn up a lot of info. 15. Garage floors that are at least six inches thick should have rebar because it provides the best support, but garage slabs thinner than that do not need rebar. Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. 1. Workmanship and jobsite conditions. (as in example diagram) First, enter the concrete slab sizes: length = 6 m, width = 4 m. Enjoy the Rebar Calculator for Slab. The slab will have 1/4" vinyl applied to the top, and we were thinking of casting the slab without control joints to prevent curling at the joints. Pour 6" fiber reinforced concrete over it. The compaction UNDER the slab is more important than the thickness of the slab. Finite elements 1st example 2nd example 3rd example. 5 to 7. Minimum thickness of concrete slab, beam, column, foundation and other structural members is selected to meet the design requirements as per standard codes. The top surface needs to remain wet while the curing process takes place. The thickened concrete slab. 9. The maximum weight of fly ash, other pozzolans, silica fume, slag or blended cements that is included in concrete mixtures for garage floor slabs and for exterior porches, carport slabs and steps that will be exposed to deicing chemicals shall not exceed the percentages of the total weight of cementitious materials specified in Section 19. 1 Storey Building: Typically, smaller diameter rebars like 10mm or 12mm might be suitable, depending on the specific design requirements. After pouring concrete walls, they are anywhere from 8 to 10 inches thick. There's no generally-accepted rule of thumb as to how to space rebar in a concrete slab. 2R for suspended floors. In the farwestern states, the rebar supplier also ordinarily places the bars, In the New York City area,…. Expansion grooves should be cut into the wet concrete to provide additional crack resistance. If the floor is. For the footing, it usually comes between 16mm to 25mm dia depending upon the size of the footing and the reinforcement bar used in compression mesh. : Theoretically there is no difference because the restraint to movement is the same in all cases. 30% carbon cont ent and only. 10. Unless you are going to park a very large truck on the slab the 2'x2' oc #4 rebar is over kill IMHO. 8 mm) when subjected to 50 pounds (23 kg) applied over 1 inch square (645 mm) of material and are greater than 1/ 8 inch (3 mm) in thickness in the uncompressed state shall not extend beneath walls, partitions or columns, which are fastened to the floor. Here:Bar Tying Requirements. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. Typically, once the concrete in the foundation wall has set, install the floor system. 5/16" 2" long bolts thru tight holes spaced 3" apart at the outer ends and then increasespacing by 1/2. worked on the rebar behavior inspection of a sustainable RC slab. The 4″ slabs-on-grade are placed on a layer of. 5 rebar, then measure and mark for your dowels at a 18. E. ,). Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the slab. rebar strength is in tension, so by adding rebar to BOTTOM of foundation, it counter acts the load of compression. 15% of the slab’s cross-sectional area), the spacing of tendons in at least one direction shall not exceed the smaller of eight times the slab thickness and 1. For example, if the first slab is at 12 inches and the second is spaced at 18 inches then measure and place your first mark at 9 inches and then continue spacing the marks at. ˘ ˘ˇ Spacing (Rebar) A-7 4-1/2” 4000 psi with 28 day aging #6 rebar 12 in. AS3600-2009 P P Lsy. No, you do not need rebar for a 4-inch slab of concrete on grade. 5 Slabs on Grade - “the purpose of isolation joints in slabs on grade is to allow horizontal and vertical movement between the slab and adjoining structures such as walls, columns, footings, or specially loaded areas (machinery bases). Rebar SizesOn studying the drawing, Length of longer side of building = 16. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. Step-4: Rebar Calculation Process Of The Slab Panel-A 4. 1. 23 Total factored load = 6. The load needs, and the span of the slab decide the spacing, size, and placement of the bars. Spacing of mechanical shear transferring devices, s, where variable from one profile to another; and . 525 mm. 6 of the International Building Code. 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. We’ll run through these ties now: Saddle ties:As per clause 11. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. Patio slabs are used in pathways. The design and spacing of expan-sion and control joints is genera l l ysee table 3 for spacing. I maintain a concrete cover of 40 MM. 4 welded wire reinforcement fabric located in the middle to the upper one-third of the slab. 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. Once you have determined that the foundation of the house is strong enough to sustain a concrete floor, lay down wood sheeting. Multiple layers of c r ossing bars cause these pro b - l e m s . 9836 – 18. 8. One-Way Slab Concrete Floors are constructed in a range of sizes with conventional spans between 6’-20’ (1. ( D) Depth of slab. , the minimum footing width or area shall comply with Table 9. Detail A: “Snap Tie” (diagram upper left) is the simplest and is usually used for rebar in a flat horizontal position. 00 m 4 3. You should still use reinforcement material, but there are other options besides rebar. This new slab design does not account for second floor installations or installations in a ground floor with a basement beneath. Type and spacing of the control and construction joints. The Rebar and Concrete in a Slab calculator computes the total length and weight of rebar and the volume of concrete needed for a slab. Check the Buckling Capacity of Rebar. A concrete slab costs between $4. That is, there are breaks in the rebar along the runs. Use 2” rebar chairs to support the rebar in the center strata of the pad. Reinforcing steel should be properly tied with wire to rigidly support it in its proper. In this video i will show you about 2nd Floor Slab Rebar. Kim Min-Koo et al. Once the concrete has gained strength to 2000 psi, typically within the 3 to 10 days recommended by PTI, the tendons are stressed. 2-inch slab and 3-inch chairs for a 5-inch slab. #LonbicooltvUsing the search function should turn up a lot of info. Marine Plywood Requirement Area of each marine plywood = 2. In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. Once you input these values, you. Figure 1 shows an example of a floor plan with a composite slab including supple - mental reinforcing bars. According to Indian standard rcc concrete roof slab thickness in residential building construction is 4 inches (100mm). (not reducing for cover/spacing, etc. To se-lect the appropriate steel area (As), use theFor example, if both slabs have rebar mats that are spaced at 18 inches and use No. The size of the columns depends on the total load on the columns. 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. The existing rebar spacing is @ 16 in. Once the wood sheeting is down, add a covering of plastic. 25 inches (13 to 56 mm) in length. If you want to combine rods of two diameters, there would. Second level 6 inches thick 9 feet tall. In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design. Add the third side. The performance of the paving joint is enhanced by these bars. If a concrete slab is 4 inches thick, the depth of the control joint should be 1 inch. By Theodore Neff. Functions of Distribution Bars In A SLAB: Distribution bar is to provide at the long span of the slab. Care should be taken to locate any reinforcement bars away from any anchor positions of the specific lift. Determine the rebar gauge. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. First, enter the concrete slab sizes: length = 6 m, width = 4 m. e. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /5. 00 m shorter span one-way floor slabs under 3. Often, concrete contractors don’t have solid runs of rebar anyway. 11. Therefore net area of slab = 201. Larger areas, lower loads, and higher seismic zones. 11 in. 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. (150 to 250 mm). With this calculator, you’re trying to calculate the dimensions of your rebar grid (length and width). After placed the (B1) R/F then placed the (B2) R/F and bound both R/F layers together by using binding wire. Rebar Spacing. 1 Flexural Cracking in Reinforced-Concrete SlabsFor mid-depth rebar, the program will use the bottom bar size and spacing options. 1 can be used for these purposes. You’ll also need vertical rebar hooks protruding at least 6” into the footing and out at least. 2 and 9. reinforcing bars. Its rebar size in inches is 0. Generally, #4 rebar (1/2 inch in diameter) is the most common size used for slab on grade applications. x 18 in. 96-8. By Concrete Construction Staff. Section 13. Floor Under Solids or Semi- solids and Single Axle load (15,000 lbs. Consider. reinforcement for the bottom fibers of the composite slab. The steel rods help reinforce the strength of the concrete slabs giving the structure a strong form. In either case, blocks should be used under the reinforcement to keep centered within the concrete. 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. Slab depths are typically between 4”-10” (10. The specified compressive strength of concrete shall be as set forth in Section R402. 1: Calculate The Main bars. Corner angle. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. Concrete volume calculator plan view diagram. 9 m in buildings with light wood-frame walls, floors and roofs, footing widths shall be determined according to. Generally, #4 rebar (1/2 inch in diameter) is the most common size used for slab on grade applications. 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. 5% of the cross sectional area of a slab. Concrete doesn't dry out; it undergoes a chemical curing process that creates a dry, solid mass. If the steel grade. 1) provides the code basis. HOUSE BUILDING IN THE PHILIPPINES - EPISODE 56: REBAR LAYOUT FOR C-JOIST SLAB Message us:Facebook: retir. 34 and $7. The more layers of rebar you have, the harder it becomes to properly vibrate the concrete. UB 610 x 179_BP_Pinned. Minimum RCC beam size should not be less than 9″x 9″ (225MM X 225MM), with an additional slab thickness of 125 MM. 5h ≤ 450mm (in areas of concentrated loads 3h ≤ 400mm) Where h is the thickness of. Generally, rebar has an immense impact on concrete. The elevation to the top of the decking (bottom of the concrete waffle slab) for forming of the second floor above-grade slab is ___. The slab is constructed on well compacted granular fill, crushed stone or marl. 2. Design of Two-way Slabs: Slabs are defined as two-way slabs when the ratio of long-to-short sides is less than 2. Selecting the correct type of rebar is as impor tant as the diamet er and grade. diameter), spaced at a maximum of 24 in. Step 1. 3 -SPACING OF TRANSVERSE REINFORCEMENT 11. the slab joint spacing should be the same as for an un-reinforced slab. 6mm. 2. 3. Map rebar and rebar patterns. 8 ). 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. The procedure: Lay up the first 4-foot height of wall. #TwoWaySlab #Basic #ConstructionWatch Basic Concept with its Practical Application by Construction AnimationJoin as member to support the channel. 87 (round up to 13)Add one rebar. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. e. 74 equals 1824 lbs per sq feet. square columns and concrete block wall supporting 10in beams @ 12ft on centers front to back. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. #4 is 4/8”, or 1/2”. 🕑 Reading time: 1 minute The design of reinforced concrete (RC) column is carried out by following certain procedures. Calculation Method For Find Out The Overlapping Length Of Beam, Column And Slab; Bar Bending Schedule For Slab And Estimation Of Steel Reinforcement In Slab; Calculation steps. 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. Specify the spacings: rebar-rebar spacing = 40 cm, edge-grid spacing = 8 cm. In low- to. Assessing General Pier Spacing Requirements In addition to the type of soil or backfill, structural loads , and weather conditions, pier spacing specifications will depend on a few other factors, such as the square footage of the home, floor plan, location of any openings, types of piers used, whether the home has one or two stories, and. Tie the slab rebar into the footing. These slabs are supported directly by the columns and have a completely flat soffit. Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of this section or ACI 332. You will be able to add radiant floor heat any time. Fill in the price and. make sure rebar is in the center of the slab, or close to it. Figure 5. )(100)/(6 in. -Multishearing. S. Two-story buildings require a minimum of 15-inch wide footings for 1,500 LBV soil. 46 and $1. Design Rules - Footing/Pile Cap Rebar. The following guidelines given below according to BS 7973-2:2001. In either case, blocks should be used under the. It has Spanish language descriptions, labels and diagrams and it also has default units in the metric system (SI). Two-Way Concrete Floor Slab with Beams Design and Detailing Design the slab system shown in Figure 1 for an intermediate floor where the story height = 12 ft, column cross-sectional dimensions = 18 in. G. These new concrete slabs do not account for second floor installations or installations in a ground floor with a basement beneath. 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. x 27 in. 7736 m 2. The spacing of such shrinkage-temperature steel cannot exceed 18 in. Rebar is tied together, using wire, to hold it in place. 1 of ACI 318-111 identifies a two-way slab as a slab system designed for flexure in more than one direction. g. g. 15. I have 3" x 6" X 16ft treated wood beams @ 3ft on center between. 20 Plant-applied External Fusion Bond Epoxy Coating [Abrasion-Resistant Overcoat] for Steel Pipe (CSA Group, formerly the Canadian Standards1) Except as provided in Sentences (2) and (3) and in Articles 9. Clause 6. Advertise Here. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808. These provisions are not meant to prohibit the use. Why Does Concrete Require Rebar? Most concrete requires some type of reinforcement. Purpose. b. , and unfactored live load = 100 psf. Crack Control – when crack widths are not checked by calculations No Further Checked Required. 5 m. 1. In the Philippines, buildings face various environmental challenges such as strong typhoons, earthquakes, and floods. 3. 00 m 7 cantilever reinforced concrete beams 18 mm for every 3. And the rebar details of (1) is 10mmØ @ 8″ c/c. 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. x 27 in. dustrial floor slab. Lower composite deck-slab weight than 3WxH-36 for the specified concrete thickness 8 inch on center low flute spacing to allow for bearing wall studs to be at 16 inches on center Non-composite deck 7⁄ 8 inch depth, 32 inch coverage 2 foot to 7 foot Span Range No Acustadek® Options Good for short span conditions1. Also note while no. 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. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. The fibers are overkill in my opinion. Heavy Loads. Free Reinforcement Calculator. Grads Slab/ Slab on grade: The slab which is cast on the surface of the earth is called a Ground slab. How far apart must rebars normally be spaced? There should be a clear distance at least equal to the bar diameter between parallel bars but never less than one inch. 6 inches. Concrete slabs-on-ground shall contain micro- or macro-synthetic fiber reinforcement. Generally, you do not need rebar for a 4-inch slab. E. Part 3. FLOOR SLABS M. on center, but this will depend on the structural design. 2. 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. Typically, once the concrete in the foundation wall has set, install the floor system. If the concrete slab in question is meant to be the footing of a house, then #5 rebar with a. 25" 3,000 PSI / 28 Day Aging #6 Rebar: 12 in: D2-10 Models: 4. 3) Shrinkage cracks: As the concrete slab dries after placement, it shrinks. Detail B: “Wrap and Snap Tie” (diagram upper right) is normally used when tying vertical wall reinforcement to hold the bars securely into. 2 – Contraction joints, states the following: “ (d) Joint depth shall be a minimum of ¼ the slab thickness for formed or tooled joints, or dry-cut sawed joints in hardened concrete (e) Joint depth shall be a minimum of 1 in. reqd identifying no. How thick should rebar be? Common Rebar Sizes Rebar in patios, basement floors, footings and driveways may vary from size 3 to 6. 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. 5" of XPS foam board underneath, 1150 square feet, 7 feet below ground. 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. 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. 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. For this case, the lift should not be installed without written authorization from theIt has stood up to some really heavy equipment for 25 years. However, the boilers I have been recommended is the Electro boiler (30,000. Low-carbon st eel is mostly iron and ferrit e with 0. 5 kPa), column spacing typicallyRepeat this process until you’ve laid all the necessary rebar. a – Main bars. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. 14 and No. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. 2. Similar “uncontrolled” or “random. , interior beam dimensions = 14 in. 5 m) with mini-mum slab thicknesses of 6 to 10 in. secondary containment floor slabs on grade. 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. ) slabs are plate elements used to form the floors of buildings. Crazing is a result of poor surface curing and only visible in hard troweled slabs. 73 per square foot for concrete installation. 2)(12 in. Specify the spacings: rebar-rebar spacing = 40 cm, edge-grid spacing = 8 cm. The main reinforcement of the slab panel “A” is marked as (1). ÞArranged bars should be strong enough not to deflect when a person steps onmaximum spacing of reinforcement in both directions. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. ** For alternate steel schedules and/or slab thickness determine As (end area of steel, in2) as shown below and use USDA NRCS Standard Drawing ES-46 to select bar size = and spacing that meets or exceeds the computed end area of steel. Number of Required Bars Formula = (Length of slab / spacing) + 1. 53 Compute moments At support: ( - ) M1 = 3. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. Technical Details of Steel Decking in Composite Floor Slabs. 4 size rebar (½ in. Use 3/8 min repair frame in the footing. 5% reinforcement (reproduced here as Table 1). In this article, we will examine the importance of reinforcing concrete with rebar and the proper steps. The tendency is to lay rebar the way one’s. 3. Placing the rebar at the bottom of the slab will provide no benefit to the concrete. The compaction UNDER the slab is more important than the thickness of the slab. Sa Episode na ito, gagawa tayo ng rebar cutting list para sa suspended slab ng 4 storey building. Drive a stake at the end. This steel runs vertically and should lap the same size reinforcing steel out of the footing. Minimum Top Rebar Spacing defined in the Slab Design Rules spreadsheet: Max Bot bar Spac: Maximum Bottom Rebar Spacing defined in the Slab Design Rules. 9 cm)-round bar 05 = part of second floor plan designated by the number 5. Space joints (in feet) no more than 2-3 times the slab thickness (in inches). ( W) Width of the slab. 3. For example, if you must splice between floors 2 and 3 of a building and you do so just above floor 2, then the construction will look like this: Pouring of column from floor 1 to 2 without the splicing rebar (but with protruding rebar awaiting the splice). 2 m top bars @ discontinuous edge Compute temperature bars 250 Using 10 mm f bars:. The spacing of the rebar is also determined by the weight and size of the slab. Minimum. That is the best way to have good concrete in such a place. Insert plate. (I think someone touched on this) Your floor covers some span. 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. Rebar in patios, basement floors, footings and driveways may vary from size 3 to 6. The term "reinforced" isn't a grade. 20mm clear cover is sufficient for intermediate floor slabs, and 30mm clear cover should be provided for roof slab exposed to rain (c). 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. Then, the new slab needs to be left alone. Reinforced concrete (R. Total Volume of concrete in cubic yards. You'd really need to know how much steel was in it to get solid data. 50 m span joist, beams, & girder soffit under 3. Whether the frame is precast, cast-in-place, masonry, or structural steel it can be accompanied by a HollowCore floor slab system. The simplest type of two-way slab to construct is known as a flat plate. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. Main bars in the slabs should not be less than 8 mm if you are using the H. To assign a Slab element to the floor, go to Assign>Wall/Slab/Deck sections. 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. The span is 2. Generally, rebar spacing in slab footings ranges from 12 to 24 inches, both for horizontal and vertical bars. Second, the slab is allowed to elongate freely in the whole length of DFR, thus reducing its strain to the value. Before placing the re-bar, correct spacing given in the detailing drawing were marked by using piece of choke on the slab formwork. We can also pinpoint the depth of every object we locate in concrete with an accuracy of +/- 10-15%. Avoid using air contents over 3% for interior slabs. Secondly, the type and diameter of steel bar used for a concrete slab’s rebar depends on the design specifications’ load-bearing capacity. The second table describes the negative (mid-span) moment demand and the bottom reinforcement. : Regarding reinforcement in slabs, please clarify whether you find a rebar spacing of 16 inches as good in reducing crack widths as a spacing of 6 or 8 inches, assuming there is the same total area of reinforcement in any case. The height of the slab bolster is determined by the required concrete protective cover. The height of the slab bolster is determined by the required concrete protective cover. Step 1. 00 m 21 reinforced concrete slab 3 mm for every 3. make sure rebar is in the center of the slab, or close to it. 9 ”x9” columns are to be used for a single-story concrete grade M15 (1: 2: 4) structure (cement: sand: aggregate). The reinforced concrete floor slab is kept free of the perimeter walls. Consequently, building such slabs requires rebar spacing knowledge. 1.