October 9, 2021. For that job, we poured a thick concrete foundation featuring #9 rebar. #4 Rebar ; The #4 rebar is often used in residential and commercial projects to add strength in slabs and columns. Most residential slabs contain reinforcement of less than 0. Rebar Spacing. A single rebar mat is only going to hold the slab together when it cracks. 375 inches, which is equivalent to 9. approximately the bar diameter in eighths of an inch [whole millimeters], used to designate the reinforcing bar size. 34 inch (8. If the steel placer is a little sloppy and places the bars at 5-inch spacing. With rebar this thick, a four-inch slab will be more durable and last longer. No, you do not need rebar for a 4 – inch slab of concrete on grade. What size rebar for 4 inch slab. Slabs, walls, and joists: #11 bars and smaller: ¾ inch. Our calculator will instantly calculate the quantity of rebar required. 6. Do you require gravel under concrete? The minimum spacing of rebar in slabs varies depending on the application, with typical spacing distances between 5 and 6 inches on center. 1 in2. Grade of steel;Size and spacing of the steel reinforcing; and. Mainly, heated slabs radiate outward rather than downward, so insulation on the edges of the slab is most important. Calculates approximate Rebar Length from total slab area and perimeter. REBAR SPACING: GP‐7 SERIES MODELS: 4‐1/​4" 3000 PSI / 28 Day Aging #6 Rebar: 12 in:. 1. 1: Calculate The Main bars. 65 and the thickness of the slab is 6 inches, M = 0. 26 inches (18" controls) #3 bar = 15. 6, the designer can exceed the CJ spacing in Table 10. thick slab, the maximum joint spacing should be. 43/30 = 0. 2. 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. 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. 75 to 3. Available Heights: 3” to 12-1/4” in 1/4” increments. 33 inches. 08 cubic yards for one concrete tube; Multiply 0. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. 8. This illustrates a common problem for the concre t e s u b c o n t ra c t o r : How do you place a l e v el slab of uniform thickness ove r steel beams that can va r y in eleva-MINIMUM VERTICAL REINFORCEMENT AND SPACING (INCHES) b, c: Soil classes and lateral soil load d (psf per foot below grade) GW, GP, SW and SP soils 30: GM, GC, SM, SM-SC and ML soils 45: SC, ML-CL and inorganic CL soils 60: 6 feet 8 inches: 4 feet (or less) #4 at 48 #4 at 48 #4 at 48: 5 feet #4 at 48 #4 at 48 #4 at 48: 6 feet 8 inches #4 at. Generally speaking, a. Placing more rebar/less spacing than required leads to higher crack width formation in slab because the higher weight of rebar would lead to higher deflection. The plastic chairs are designed for the rebar rods to snap easily into. 561 kg/m. The string will act as a guide to keep the form boards straight. If the slab in question is just for a patio or a similar purpose,. 2-inch midspan c a m b e r, the beam delive r ed to the jobsite might have a 13⁄ 4-inch cam-b e r. Beams and columns: 1½ inches. 16 wire longitudinally and smooth No. H3: #8 Rebar (8 rebar size). Tractor. For one layer of 6x6 W1. Number 4 rebars spaced 12 inches on center (center-to-center distance) on both the top and bottom faces and in each way as well, i. For example in a slab of 6-inch depth, a rebar of 6/8 inch will be used. Joint distance (D) or tank diameter in feet based on Steel Schedule Minimum end area (As) of steel (in2) for slab thickness, t= 5 inch *1. First, Get The Number Of Required Bars. But to get two layers in an 8" slab-on-grade where the bottom cover is 3" would might violate the bar to bar spacing between layers. 13. Tying should include bars near the ends of the bridge and bars near the curbs. 4 inch of p r otection. Rebar grid for concrete Slab Foundation. Wood sole plates at all exterior walls on monolithic slabs, wood sole plates of braced wall panels at building interiors on monolithic slabs and all wood sill plates shall be anchored to the foundation with minimum 1 / 2-inch-diameter (12. MAX and #5 top placed at center of slab" I installed the #3 dowels 12" apart and 6" into the existing surrounding floor. It has stood up to some really heavy equipment for 25 years. The minimum thickness of reinforced concrete pavements should be 6 inches, except that the minimum thickness for driveways will be 5 inches and the minimum thickness for reinforced overlays over rigid pavements will be 4 inches. 1% reinforcement in a 4-inch thick slab is #3 bars in both directions at 24-inches. concrete is good in compression but not tension. 2(1) shall be air entrained as specified in Table R402. A 4 – inch -thick slab cast on the ground and in permanent contact with it will float and rebar is not required. 2 mm in diameter. Guidance for joint spacing to minimize out-of-joint. I used no. The concrete contractors said that these rebar chairs were a great idea, but the execution and labeling of the product was very poorly thought out. 34 and $7. 4 and by diameter in inches above No. 2. 2-1/4 inch rebar high chair is designed to hold rebar in place during concrete applications. 6 bars and bigger – 2 inches. Does a 4-inch slab need rebar? By: Olin Wade (Remodel or Move Stuff) Watch This Video To Learn More About Using or Not Using Rebar For Concrete Driveway Watch on It. If you prefer to calculate the number of bags of concrete needed, you can use the weight of the bags as a reference. Wood sole plates at all exterior walls on monolithic slabs, wood sole plates of braced wall panels at building interiors on monolithic slabs and all wood sill plates shall be anchored to the foundation with minimum 1 / 2-inch-diameter (12. The grade shall be as specified by the. ) = 0. What should be the size rebar for a 4-inch slab? For a 4-inch slab, the thickness of the rebar should be ⅛ of the slab. Use unwashed material that has a top size of 11/4 inches and includes smaller sizes right down to the fines; the irregular shapes and sizes interlock nicely when compacted. For example, the percentage of reinforcement of a 30-inch slab with two layers of No. If shear reinforcement is required for in-plane strength, s shall not exceed the smallest of 3h, 18 inches, l w /3. Plan out your control joint spacing 24-36 times. Can I pour concrete directly on dirt?Placing 0. 4/1. Divide 27 cubic feet of concrete in a cubic yard by the volume of the concrete bag. In slabs with an average thickness of less than 6 inches, the spacing should be. 2 mm in diameter. It will be different from the concrete right next to it. For flatwork, such as slabs-on-grade and driveways, a minimum thickness of four inches is required, but increasing the thickness to five inches can add nearly 50 percent to the load-bearing capacity. The design of one-way slab is simple and can be carried out easily. e. There are 27 cubic feet in a cubic yard of concrete, so divide the total cubic feet by. 9. Ask Your Own Structural Engineering Question. 5 inch line of your patio slab to keep the dowels in the upper portion of the slab. Similarly, a 4 inch slab of 4,000 psi concrete, 4 feet by 8 feet, with reinforcing mesh can hold up to 45,000 lbs. Convert your longitude measurement into inches: 15 x 12 = 180. Having installed thousands of slab on grade foundations over some 26 years as an ironworker, I can say that if it was my driveway, I would probably do 5 inch thick concrete with #4 rebar at 18 to 24 inches each way at center of slab in other words 2" chairs or dobies at every intersection and deepened perimeter footings. Set the forms at the proper height before bringing in the last lift. Placing WWR in Two-Course WorkGenerally, a #4 (1/2-inch diameter) or #5 (5/8-inch diameter) rebar should be sufficient for most residential and commercial applications over a 6-inch slab. The 2021 IRC® contains many important changes such as: Braced wall lines must be placed on a physical wall or placed between multiple walls. Emergency escape and rescue openings require a clear 36-inch-wide path to a public way. Sub-Grade and. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Do you need rebar for 4 inch slab? No, you do not need rebar for a 4 – inch slab of concrete on grade. Others say rebar in the middle is a waste. Generally, lighter-duty applications require a rebar spacing of 8-12 inches (20-30 cm), while heavier-duty applications require a closer spacing of 6-8 inches (15-20 cm). A little more cash now is worth no cracks later but I always overkill. For example, if the engineer calls for rebar spaced every 4 inches, you need to place three bars for every 12 inches of the form. 5 inches of thickness at the edge of the pool. (Video) Rebar Spacing, Made Easy (DesignBuildDoug). For beams, these distances are 300 mm, 180 mm and 150 mm for grades of main reinforcement of Fe 250, Fe 415 and Fe 500, respectively. In general, it will be necessary to provide supports for reinforcing steel in deck slabs and overhangs, railings, bent diaphragms, intermediate diaphragms, bent caps, approach slabs and culvert slabs. Using rebar in a 4-inch slab provides a multitude of benefits, enhancing the structure’s strength, stability, and durability. Rebar being #4 grade 60. 5. ) In metric the bar size is approximately its diameter in millimeters: a 25 bar is 25. 5 times the slab thickness in inches. Thickening the structure along the perimeter by another will serve as an integral footing, adding strength where the loads are. 33_2_0. To calculate the amount of rebar per square foot, you will need to convert the 6 foot length to a linear foot, and the 50 pounds to pounds per linear foot. 525 mm. inches thick and about 4 x 4 inches square. Product Details. The pitch of the main bars shall not exceed the following:This is done by inserting #4 rebar dowels a minimum of 6 inches into the center of the footing’s wet concrete, spaced typically at 4 feet on center. on 3 feet- 6 inch square area (office for some codes) CONCRETE MIX Top size of the coarse aggregate should not exceed 3/4inchor as dictated by applicable codes. 8 mm) ±1/2 inch (±12. Rebar is recommended on concrete measuring 5 – 6 inches thick. 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). A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. (i) The maximum spacing between two parallel main reinforcing bars shall be 3dor 300mm or whichever is less, and. For example: A #5 [#16] bar is approximately 5/8 inch [16 millimeters] in diameter: a #9 [#29] bar is approximately 9/8 inches [29. 2(1) requires that half the calculated span. of 6" imbediment. For the slab's longer dimension, you'll need 360 inches divided by 14, which gives you 25 plus a bit left over. If you have any concerns about the soil or drainage in your yard, you may need to pour an even thicker slab. Contact splices. 11. Step-4: Rebar Calculation Process Of The Slab Panel-A 4. Do you need rebar for 6 inch slab? Rebar is recommended for. 23 inches For a 4" thick slab with GR60 bars I get the following max. apart. 60 per square foot for materials and labor. For larger slabs, cut control joints into the surface to accommodate shrinkage and changes in temperature. #5 bars are 5/8”. 15 per cent of the gross sectional area. ) (12 in. I am confused about the grid. 6 inch slab and have walked many a crawler on it with no signs of cracking. 10. Anchor bolts are located a minimum of 1 3 / 4 inches (45 mm) from the edge of the concrete parallel to the length of the wood sill plate. In order to calculate this, you need to input the length and width of your slab. 4" is plenty, be sure the base is good - compacted, free draining, etc use a relatively tight mix, ie low water to cement ration, slump in the 3 to 3. A cubic yard of concrete—equivalent to 27 cubic feet—will cover an 81-square-foot area with 4-inch-thick concrete and cost $113–$126. With our rebar calculator, you can eliminate. For corrosion protection, however, most specifications require a minimum depth of concrete cover that usually ranges from 1 inch to 2 inches. Spacing of bar supports depends upon the size of the reinforcing bar being supported. Vertical placement tolerance for reinforcement in slabs-on-ground is ± 3/4 inch from the specified location. 5 times the thickness in inchess of the slab and the length to width does not exceed 2 to 1. and type of reinforcement bars are crucial to the success of any project. To use our rebar calculator, simply input the dimensions and specifications of your project. 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. View More. It has a foot print of four tires about 10 inches by 10 inches time 4. Each example is for an 8-inch-thick in-dustrial floor slab. Set the forms at the proper height before bringing in the last lift. No. The ends of the bars should be two or three inches from the sides of the form to protect the rebar from the elements. Cracking is really due to a number of causes. However, for thicker slabs, such as those between 4 and 8 inches thick, 3/4 inch rebar is usually used. Having more bar would only increase the strength of the slab, as long as. 2. Common size of rebar used for 4 inch slab, it may vary from size. For patios, a grid spacing of 24 inches is. 2. CRSI’s Reinforcement Anchorage and Splices includes tables of required lap splice lengths based on these variables. Rebar counteract this force. x 6 · W4. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. Common size of rebar used for 4 inch slab, it may vary from size. If you have a 5 inch slab and multiply it by 24 to 32 you will find that your joints should be placed every 120 to 180 inches or 10 to 15 feet; Or another way to figure this out is to times it by 2 or 3 in feet. 1. For a 400 square foot slab, the man hours required to finish a two-car concrete garage slab is about 13 hours. How do you calculate rebar for a slab? Layout of Rebar for Concrete Slabs. Do You Need Rebar For A 4 Inch Driveway Slab? A 4 inch concrete driveway slab is too thin for rebar. I just got off the phone with a local contractor after picking his brain a bit and he typically will use a #4 bar @ 48" o/c. However, generally, a 6mm rebar is suitable for a 4 inch slab. It create a bending of the slab. diameter. Whatever you do, please don’t pour a gigantic slab of concrete with no. For example in a slab of 6-inch depth, a rebar of 6/8 inch will be used. The installation of the rebar is critical for the success of the overall project. When you build a 4-inch slab, you’ll need a higher grade of rebar. For ½“ rebar the inside of the bend should have a diameter of at least 3 inches. Content intended for mature audiences. Rebar can be beneficial and provide added strength in a 4” inch slab drive way. Rebar is short form of reinforcing bar, it is steel bar or Steel wire provided as tension bar, used in. If you chose to put rebar in a four inch garage slab, your rebar should be spaced at least four inches and up to twelve inches apart. Provide Construction Joints (ie, transverse joint) @ 40'-0" intervals if you have a long driveway. Reading time: 4 minutes. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required . Secure your rebar in place when pouring concrete with our Plastic Rebar Chairs. The process for putting rebar in concrete is relatively straightforward. What is the minimum reinforcement in slab? 2- Slab Reinforcement Details. What should be the size rebar for a 4-inch slab?. Supporting the rebar during the concrete pour is. Minimum sub-base (stone) under slab shall be 4 inches for both Table 1 and Table 2. The Rebar calculator for slab is best to find the Rebar size. 5 mm) for concrete slab depth ≤12 inch (304. Where: As = cross-sectional area in square inches of steel per lineal foot of slab width t= thickness of slab in inches fr = tensile strength of concrete (psi) = 0. On average are required, for 10 square meter with 12cm thick slab, 19 strips of 3/8” rods (9ml each one), are 171 ml. Tie in the Rebar to Strengthen the Slab. 33 ft). I was thinking of the following: basement wall 8 inches thick 10 feet high backfilled up to 7 to 8 feet. For example, if the engineer calls for rebar spaced every 4 inches, you need to place three bars for every 12 inches of the form. Rule of thumb is to have the minimum clear spacing between bars be 1. These dowels could be straight or have a hook in the bottom and only need to be a minimum of 16 inches high above the finished concrete. Typically, for residential construction, you might use #4 (1/2 inch) or #5 (5/8 inch) rebar spaced at 12 inches on center for a 4-inch thick slab and closer spacing for a 5-inch thick slab. 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. Concrete shall have a minimum specified compressive strength of ƒ' c, as shown in Table R402. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. anchor bolts and the 4 inches (102 mm) φ pipes. Have a helper add or remove concrete in. Second, most designs require’spacing rebar’ of two inches. Matt, You need to tie the new footing and foundation wall into the existing structure's footing and foundation wall, so yes drill and epoxy the rebar in. For most residential slabs, such as patio slabs and sidewalks, #4 rebar (1/2-inch diameter) spaced 12 inches apart is recommended. o Minimum 6 inch thick continuous concrete footings not less than 18 inches wide and reinforced with two continuous #4 rebar rods. Rebar Spacing; D2-8F: 4. Concrete has great compression strength, but it can crack or br eak under. If the slab is expected to bear heavier loads, such as from heavy vehicles, then larger diameter rebar or closer spacing may be required. Most concrete slabs last 30–40 years and can last up to 100 years if properly installed and sealed. 5-inch cover to the beam stirrups, dagg = 3⁄4. 23 inches For a 4" thick slab with GR60 bars I get the following max. The laps should be tied together with wire. Rebar helps prevent cracks from growing wider largely by preventing cracked slabs from moving apart. All thick slabs can be categorized into:. 13-4. d. For 0. 25" 3,000 PSI / 28 Day Aging #6 Rebar: 12 in: D2-10 Models: 4. Spacing of bar supports depends upon the size and placing of the rein-forcing bar being supported. For a 4-inch concrete slab-on-ground, this would be equivalent to #4 rebar spaced at 10 inches each way. 24-foot joint spacing. 10” or so around the edge and 4” everywhere else. Horizontal rebar is. For unbonded topping, the minimum thickness is 75 mm. (iii) three-fourths the minimum specified clear spacing between individual reinforcing bars or wires. Second level 6 inches thick 9 feet tall. A. For very thick slabs, such as those 8 inches or more in thickness, half-inch rebar or larger is used. Rebar is typically calculated at a rate of 1 for every 8 inches of footing width. 3a, for two-way slabs without interior column. 376 lbs/ft or 0. 5. To find the exact size of the slab by slab Rebar calculator. Minimum reinforcement in either direction shall be 0. All 3/4 inch diameter anchors must be a minimum of 6 inches away from any expansion seams, control joints or other inconsistencies in the concrete. We followed all of those and 2 years later we're glad we did!1. ±3/8 inch (±9. In some cases, concrete needs reinforcement with steel mesh. (f) Curtailment of bars in slabs Curtailment of bars is done according to the moment envelope. Hercules 3 in. 1 Type A - The dowel structure shall comprise a single metallic material meeting the requirements of AASHTO M 255M/M 255, AASHTO M 334, ASTM A276, ASTM A312, or ASTM A1035 (CS, CM and CL). 5 range tops, and control joints are formed either with preformed joint material or sawcut within the first 24 hours and be sure that the curing conditions are good, at least 50 F. The size of the rebar depends on the specific project, with #3 rebar suitable for driveways and patios, and #4 rebar recommended for walls, piers, or columns. For slabs and pads, the distance between rebar is normally 4-6 inches apart. Concrete Floor Rebar Spacing. Rebar should be placed evenly throughout the project. A good compacted base below the concrete is equally important. Video of the Day Step 2: Dig Out the Area Excavate the concrete pad area 6 inches deep to prepare the ground for the concrete. It is essential to check local codes and regulations before starting any construction project. Concrete is not strong in tension and the rebar is. 1. For a flat slab, such as a driveway, consider placing the rebar in an 18 inch grid spacing, keeping the edge rebar at the same distance from each side. Add 5%-10% additional material for some waste or spills. 12. In order to calculate this, you need to input the length and width of your slab. ±3/8 inch (±9. (i) The maximum spacing between two parallel main reinforcing bars shall be 3dor 300mm or whichever is less, and (ii) The maximum spacing between two secondary parallel. How to lay a concrete slab. 84 m; grid. basement foundations). When a load is applied it bends the concrete on end, this is how the crack starts, the point of failure. For example, if the area is 10 feet long and 6 feet wide, the square footage is 60 feet. 0 inches use 4 inch Schedule 40 PVC duct and internal joining coupling for 4 inch I. (ii) The maximum spacing between two secondary parallel bars shall be 5dor 450 mm or. e. 7 mm) anchor bolts spaced a maximum of 6 feet (1829 mm) on center or approved anchors or anchor straps. Read more on low-shrinkage concrete mixes in the Concrete Mix Design section. The appropriate rebar size depends on the project, with #3 and #4 being common choices. 6 rebar spaced 4 inches on center is P = 8. BAND—Group of reinforcing bars distributed in a slab or wall or footing. ) In metric the bar size is approximately its diameter in millimeters: a 25 bar is 25. For a 4-inch slab, #3 rebar should be spaced 12 inches apart on center. When a=4. Rust is visible where some of the bottom bars are at the bottom of the slab, and some rebar ridges are faintly visible. For building footings I would use a #5 (5/8 inch) rebar. Vertical placement tolerance for reinforcement in slabs-on-ground is ± 3/4 inch from the specified location. surface. depth of standard 2x4s. 7 mm). In inches the diameter of a #5 rebar is 5/8″ and that of a #4 rebar is 1/2″. There are three different sizes of rebar typically used for home construction projects. 014/4 = 0. For the slab's longer dimension, you'll need 360 inches divided by 14, which gives you 25 plus a bit left over. If the slab is expected to bear heavier loads, such as from. Then I’d make sure that slab gets cut up the very next day after the pour so it can crack where you want it to. Where: As = cross-sectional area in square inches of steel per lineal foot of slab width t= thickness of slab in inches fr = tensile strength of concrete (psi) = 0. For a flat slab, such as a driveway, consider placing the rebar in an 18 inch grid spacing, keeping the edge rebar at the same distance from each side. If the slab is 4 inches or less than it should not be reinforced. (3) #4: Three number 4 rebars (usually used when the rebar perpendicular to the detail) #3 ties @ 9 OC, (2) per set: Number 3 rebars used as stirrups, spaced at 9 inches on center. Concrete needs rebar to be as strong as possible; however, if poured thin enough and used only for walking, you can quickly go without rebar. Anyhow, the rebar chairs are relatively cheap. Slabs, walls/dividers, and joists – 11 bars and littler – ¾ inch. 64 mm) between longitudinal rebar 2 and 3, which is the same as the rebar construction and traditional tape measurement results. For example, if you are using ½ inch rebar, divide 60 feet by 0. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. 9 3 in. A six inch slab can handle some thin spots - a 4" slab can't. ( D) Depth of slab. Calculate Rebar Spacing, Layout and Weight in a Concrete Slab To calculate Concrete and Total Rebar in a multi sided slab see: Calculate Concrete and Rebar in Multi Sided Slabs 16 Bars @ 11'- 6" 10 Bars @ 19'- 6" Total Length 420 ft Includes 10% waste / lap Exact Spacing Length 16" mid 10" Width 16" mid 10" 21 x 20 ft Lengths $ (Enter Cost per Bar) See full list on everything-about-concrete. area = 25′ × 25′. 4m2. For example, for a one-way solid slab with #5. Rebar Chair is a patented polypropylene support system ideal for concrete applications requiring a 6 in. The percentage of reinforcing refers to the cross-sectional area of the steel for a given width of slab divided by the cross-sectional area of the slab area considered. Expansion grooves should be cut into the wet concrete to provide additional crack resistance. Generally, you do not need rebar for a 4-inch slab. For thin slabs, such as those less than 4 inches thick, the most common size of rebar used is 5/8 inch. The concrete contractors said that these rebar chairs were a great idea, but the execution and labeling of the product was very poorly thought out. Swimming Pool: The minimum rebar sized to be used for a residential swimming pool. To reinforce a 4” concrete slab or driveway with steel rebar, determine the grid spacing and rebar size – #3 or #4 in a 12” to 18” grid. For driveways and patios, #4 (1/2 inch diameter) rebar is a common choice. The spacing of the rebar should increase to between 18 and 24 inches apart for slabs between four and six inches thick. 5-inch cover to the beam stirrups, dagg = 3⁄4 inch, #3 stirrups used with #4, #5, and #6 longitudinal bars, and #4 stirrups used for #7 and larger longitudinal bars. Tying rebar at joints and positioning it in the middle of the slab is essential for proper reinforcement. It's not a problem to get two layers in on an interior 8" elevated slab where the bottom cover is 3/4". The spacing is highly dependent on the concrete mix's shrinkage potential. 8" - 3/4" (top cover) - 2" (4-#4 bars) - 3" (bottom. For example, one-way slab thickness. The diameter of bar generally used in slabs are: 6 mm, 8 mm, 10 mm, 12 mm and 16 mm. For concrete not presented to climate or in contact with the ground: chunks, dividers, and joists – #14 and #18 bars – ½ inch. 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,. 2-1/4 inch rebar high chair is. Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the slab. The appropriate rebar size depends on the project, with #3 and #4 being common choices. For garage slabs, two rows of #4 rebar are recommended around the perimeter, one above the other. New concrete slabs must conform to the above. 10% reinforcing, the slab joint spacing should be the same as for an un-reinforced slab. (as in example diagram) Multiply the 2. 2. I would suggest 3000 psi concrete if cracking and wearing is a concern, but 2500 psi is ok. ( W) Width of the slab. 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. The main reinforcement of the slab panel “A” is marked as (1). B3030. Build forms. 87 d Spacing of bar = Design of Continuous Slab Suppose a slab is supported at the ends and also at intermediate points on beams, the maximum sagging and hogging moments to which the slab is subjected to due to uniformly distributed load, can be computed as follows: Let = intensity of dead load per square metre. This means 2x 3/8 inch rebar makes 3/4 inch of steel. Special surface finishes, including coatings. Dosage amounts shall be from 0. 17 inches (18" controls) #3 bar = 10. 6. The sill plate is 2-inch (51 mm) or 3-inch (76 mm) nominal. Most reinforcing bars bearing a Metric diameter markNow, divide each measurement by the 14-inch spacing. 2. Step-4: Rebar Calculation Process Of The Slab Panel-A 4.