For commercial loaded slabs I go 3000 psi minimum, and usually 4000 psi. Suppose you have a concrete slab with dimensions 10 feet by 8 feet by 6 inches, and you plan to use #4 rebars with a spacing of 12 inches. anchor bolts and the 4 inches (102 mm) φ pipes. a car weight about 5000lb. Use 2” rebar chairs to support the rebar in the center strata of the pad. Slabs for septic tanks may require the use. Most masons just round up to 5 inches. If the concrete slab in question is meant to be the footing of a house, then #5 rebar with a. Use 2” rebar chairs to support the rebar in the center strata of the pad. H3: #8 Rebar (8 rebar size). It is also important to consult a structural engineer or professional mason to ensure the optimal rebar spacing is being achieved for the specific concrete foundation. CONTROL JOINT SPACING. construction projects. For slabs of septic tanks, you usually use #3 and #4 bars. How far apart do rebar bars need to be placed? Place rebar in a grid pattern with a spacing between bars of. Rebar should be placed evenly throughout the project. New concrete slabs must conform to the above. apart and pack soil against them. For example, a size 4 rebar will have a diameter of 4/8” or ½ inches. Click HERE for spec sheet. For a standard 6-inch thick concrete slab, you will need between 6 and 7 pounds of rebar per square foot. Cracking is really due to a number of causes. ) (12 in. When rebar is used, it needs to be laid slightly above the center or in the center of the thickness of the slab, with a spacing of 12 inches. As a minimum, #4 rebar (1/2 inch) is spaced vertically at 36 inches on center, continued to within 8 inches of the top of the wall, placed on the tension side -- the inside face -- of the wall. The appropriate rebar size depends on the project, with #3 and #4 being common choices. Most reinforcing bars bearing a Metric diameter mark Now, divide each measurement by the 14-inch spacing. 3. If rebar is used what should the spacing and size be?What size rebar do I need for a 6 inch slab? The size of rebar that you need for a 6 inch slab depends on a variety of factors including the type of construction and the specific design of your structure. Do you need rebar for 4 inch slab driveway? It depends. spacings: #4 bar = 27. lengths of rebar to just below. Choose Round Column (or Round Slab) on the calculator; Enter Height 4 ft (or 48 in) Enter Diameter 10 in; Calculate and the answer is 0. If the floor is designed as a reinforced-concrete slab requiring rebar in the tension zone, the designer should specify the correct rebar position. If the slab is expected to bear heavier loads, such as from heavy vehicles, then larger diameter rebar or closer spacing may be required. 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. Minimum sub-base (stone) under slab shall be 4 inches for both Table 1 and Table 2. For example, if both slabs have rebar mats that are spaced at 18 inches and use No. 2 mm in diameter. 375 inches, which is equivalent to 9. Steel rebar mesh (6-inch) or rebar rod Rebar ties 4 two-by-fours, each 12-foot 4 two-by-fours, each 8-foot Twine Concrete release agent Screws, 3-inch 25 Dobies, 2-inch high OR 2 1/4-inch high rebars. Generally, you do not need rebar for a 4-inch slab. 65*6) = 1. ( W) Width of the slab. 64 mm) between longitudinal rebar 2 and 3, which is the same as the rebar. 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. You can use regular fencing material with 2' x 4' or 2' x 6' mesh. Suggested applications - concrete slabs, precast, tilt-up, bridge deck, and other heavy applications. It’s crucial to ensure that welded wire mesh be placed on chairs of the proper height. And rebar is sized by eights of an inch. Then use a “gauge board”—a 1×4 with blocks screwed to it—to position the other side. 2. c. They're compatible with rebar sizes #3 to #5 and can elevate your rebar either 1 1/2 inch or 2 inches off the ground. 1% reinforcement in a 4-inch thick slab is #3 bars in both directions at 24-inches. When long slabs are used, special consideration must be given to joint design and sealant require-ments. That's 144 square inches. For a 6 in. New concrete slabs must conform to the above stated properties before installation of. Generally speaking, a. You might be interested: Readers ask: Pavers Vs Concrete? The size of rebar that is needed for a 6 inch slab will depend on a few things, such as the type of load the slab is being used for and the spacing of the rebar. 23 inches For a 4" thick slab with GR60 bars I get the following max. This will provide adequate reinforcement for most applications. To use our rebar calculator, simply input the dimensions and specifications of your project. Generally, rebar spacing in slab footings ranges from 12 to 24 inches, both for horizontal and vertical bars. 75-in 500-Pack Polypropylene Rebar Chair. 2 only if the steel reinforcing is greater than 0. 4. 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. First, Get The Number Of Required Bars. If you are in a climate subjecting the floor to freezing, get air added to the concrete. In conjunction with the bar callouts in Figure 1, minimum extensions for the top and bottom reinforcing bars in the column and middle strips must be provided. For example, #8 rebar = 8/8 inches (or 1 inch) in diameter. Find the number of concrete bags in the most popular sizes in the chart below: Bag Size. 1 in2. 34 and $7. The typical depth for rebar placement for slabs is 2-4 inches. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. The string will act as a guide to keep the form boards straight. I would suggest 3000 psi concrete if cracking and wearing is a concern, but 2500 psi is ok. Provide 21" minimum rebar splice laps. Concrete has great compression strength, but it can crack or br eak under. You can't get that in a four inch slab. You’re likely to pay between $1,800 and. For example, let’s say the project requires a 4 inch thick slab, made of 6 foot rebar and a total of 50 pounds of rebar. In general, you’ll want a slab that is at least 4 inches thick, but 6-8 inches is even better. 4m2. The installation of the rebar is critical for the success of the overall project. Pour footings and wall. As well as that, the calculator will also tell you. 78. It's not a problem to get two layers in on an interior 8" elevated slab where the bottom cover is 3/4". 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, a slab that is 6 inches thick might have rebar marked as size 6 or 3/4-inch. Methods used for finding slab thickness varies for different types of slabs. 75-in x 1. Rebar is recommended on concrete measuring 5 – 6 inches thick. depth of standard 2x4s. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. 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. 1R-89, "Guide for Concrete Floor and Slab Construction," ACI Committee 302 does not recommend keyed joints for slabs thinner than 6 inches, and also doesn't provide guidance for dowels in slabs thinner than 5 inches. For unbonded topping, the minimum thickness is 75 mm. If you are in a climate subjecting the floor to freezing, get air added to the concrete. But if you feel that the slab is in a sensitive position and extra protection is needed, you can add rebar to it. 15% for mild steel bars (Fe250, Fe415). To find the exact size of the slab by slab Rebar calculator. 5000 PSI concrete can safely support 5000 pounds per square inch (PSI) minimum before its compressive strength is overcome. 35 to $6. diameter. 7 mm) anchor bolts spaced not greater than 6 feet (1829 mm) on center or approved anchors or anchor straps. User note: About this chapter: Chapter 4 provides requirements for constructing footings and walls for foundations of wood, masonry, concrete and precast concrete. If the wall exceeds four feet in height, footings should be poured. 65 and the thickness of the slab is 6 inches, M = 0. Concrete Slab Rebar Spacing Guideline. Grade of steel;Size and spacing of the steel reinforcing; and. 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. The compacted aggregate base is first, followed by a 6 mil polyethylene vapor barrier, then insulation, then rebar or wire mesh, or both. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. 1. Concrete Floor Rebar Spacing. B3030. 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. o Minimum 3-1/2 inch thick continuous concrete slab footings not less than 48 inches and reinforced with approved fibers, or with 10 gage 6 inch x 6 inch wire fabric. For a 4 inch slab, I really wouldn’t space the bars further apart than 12 inches. 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. 2(1) shall be air entrained as specified in Table R402. There should be a minimum of 3 inches of clear cover from the fi nished surface of the slab. For example, if both slabs have rebar mats that are spaced at 18 inches and use No. This will be based on the loads and desired strength of the concrete. 1. 5 inch line of your patio slab to keep the dowels in the upper portion of the slab. Plan out your control joint spacing 24-36 times. But if one should choose to reinforce their concrete patio, the reinforcement bar they should use should be a size #3, which is 3/8 in diameter. 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. Non-reinforced slabs – where no. Generally, for a standard residential foundation, the minimum spacing between rebar should be at least 4 inches. Main reinforcement which is based on the maximum bending moment shall not be less than 0. 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. 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. 2(b). 23 inches For a 4" thick slab with GR60 bars I get the following max. 7. The maximum anchor nominal diameter is 5/8 inch (16 mm). How to calculate the rebar quantity from concrete? Convert your longitude estimation into inches: 15 x 12 = 180. 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. Common practice is to place supports 2 to 3 feet apart. To truly reinforce concrete, the percentage. inches thick and about 4 x 4 inches square. Average: Rebar in Concrete Slab Estimator. Table 1-Minimum Shrinkage and Temperature Reinforcement steel for non-SES floors or SES floors with a secondary liner. There has been some research in recent years to look into this as a bridge deck with no rebar is a bridge. 46 and $1. The size of rebar that is needed for a 6 inch slab will depend on a few things, such as the type of load the slab is being used for and the spacing of the rebar. A 6" slab is quite minimal for most bridge deck applications. 3 of the Eurocode 2. Rebar will hold a force in tension. 1. (inches) Slab Bolster 3/ 4 to 3 high; Supports lower slab SB 2, 3, 12, 36 long reinforcing steel; also comes in circular shape for architectural work. For example, a 4 inch slab of 3000 psi concrete, 4 feet by 8 feet, with reinforcing mesh will hold up to 34,800 lbs. Leave a few inches of space between the mesh and the edges of the forms to prevent rust. Video of the Day. 2)(12 in. For example, let’s find the number of 5′ x 50′ rolls of mesh required to reinforce a slab that is 25′ by 25′. For example in a slab of 6-inch depth, a rebar of 6/8 inch will be used. That solution would be for a monolithic pour on base material compacted to a min. 4. The architect's instructions on the plan are: “New conc slab with #3 transverse bars at 12” O. 60 per square foot for materials and labor. An 8-inch slab or thicker is required for CJ’s spaced up to 20 feet. Nathaniel P. Many other styles of supports are available and effective. Reinforcement for Slab. That way you can use the forms themselves as a guide for the final base height. Similarly, rebar with a size 15 will be 15/8 inches. Second level 6 inches thick 9 feet tall. 43/30 = 0. 11. Provide adequate joint spacing:. 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. 440 3. Generally speaking, a. In that case, a layer of rebar near the bottom or at. 08 x 50 = 4 total cubic yards of concrete for 50 tubes4. Hercules 3 in. How to calculate the rebar quantity from concrete? Convert your longitude estimation into inches: 15 x 12 = 180. 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). What size rebar for 4 inch slab. 74 equals 1824 lbs per sq feet. When a load is applied it bends the concrete on end, this is how the crack starts, the point of failure. To calculate Total Area of a multi sided slab, first divide the shape into rectangles or squares. All thick slabs can be categorized into:. Likewise, the top reinforcing mat is to be tied to the bottom reinforcing mat on a 4 foot grid in floors of concrete slab bridges. The spacing and quantity of the rebar will depend on factors such as the load the slab needs to support and local building codes. Generally I would go with the #4 rebar (1/2-inch diameter) since the difference is cost should be negligible and it provides better construction (there should not be any splices in the rebar on a slab this small). First, find the area of the slab. 6. . The rated separation for two-family dwellings is 1 hour whether or not a lot line exists between units. The string will act as a guide to keep the form boards straight. Product Details. If you prefer to calculate the number of bags of concrete needed, you can use the weight of the bags as a reference. By understanding these basic. Thread starter matt_isserstedt; Start date Feb 18, 2015; Replies 30 Views 72,127 1; 2;. There are three different sizes of rebar typically used for home construction projects. For a 4-inch slab, #3 rebar should be spaced 12 inches apart on center. Lay down wire mesh or rebar on top of the sub-base if necessary. If the steel placer is a little sloppy and places the bars at 5-inch spacing rather than 4-inch spacing, the product's strength will be reduced by 20%. The maximum height of a 4-inch (102 mm) load-bearing masonry foundation wall supporting wood-frame walls and floors shall be not more than 4 feet (1219 mm). The spacing of the rebar is also determined by the weight and size of the slab. Reinforced slabs – where welded wire mesh or rebar is used to reinforce the slab. The tools you need to build a concrete slab. Rebar being #4 grade 60. 6. 058 percent, which is only enough for crack containment. A 4 – inch -thick slab cast on the ground and in permanent contact with it will float and rebar is not required. Using the rebar tying tool, twist wires around the intersections of the bars. Specify the spacings: rebar-rebar spacing = 40 cm, edge-grid spacing = 8 cm. Driveway : The total cost of a concrete driveway will depend on size. For more complex projects (i. Each example is for an 8-inch-thick in-dustrial floor slab. 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. that is 2. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required . 34 inch (8. However, for thicker slabs, such as those between 4 and 8 inches thick, 3/4 inch rebar is usually used. A six inch slab can handle some thin spots - a 4" slab can't. For very thick slabs, such as those 8 inches or more in thickness, half-inch rebar or larger is used. Rust is visible where some of the bottom bars are at the bottom of the slab, and some rebar ridges are faintly visible. It has stood up to some really heavy equipment for 25 years. (ii) The maximum spacing between two secondary parallel bars shall be 5dor 450 mm or. 8 mm) ±1/2 inch (±12. In order to calculate this, you need to input the length and width of your slab. And the rebar. 5-inch cover to the beam stirrups, dagg = 3⁄4. Drag a straight 2×4 (screed board) across the top of the concrete forms to level the concrete. We would like to show you a description here but the site won’t allow us. 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. 15 per cent of the gross sectional area. 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. 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. 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. For flat slabs, grid spacing of 18 inches for driveways and 24 inches for patios is recommended. The spacing of the rebar is typically 12” on center for most residential applications. 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. The plastic chairs are designed for the rebar rods to snap easily into. The sill plate is 2-inch (51 mm) or 3-inch (76 mm) nominal. I've only ever called out a single layer in a 8" s-o-g. 2-1/4 inch rebar high chair is designed to hold rebar in place during concrete applications. Concrete volume calculator plan view diagram. No, you do not need rebar for a 4-inch slab of concrete on grade. Step 5 – Place the Mesh. The laps should be tied together with wire. No, you do not need rebar for a 4-inch slab of concrete on grade. aggregate, you'd need 1. Fiber and welded wire are only used for shrinks cracks, non structure cracks, cosmetic cracks. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the 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. 5 (1), or as specified by engineered design accepted by the building official. For patios, a grid spacing of 24 inches is. 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. #4 is 4/8”, or 1/2”. in thickness, columns, walls, and parapets. 12% for HYSD bars and 0. Type and spacing of the control and construction joints. Rebar is used t o help improve concrete’s resistance to loads andThe maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. Nail the corners together, and place the form on the graded gravel, making sure it doesn’t rock. For flat slabs like driveways and patios, spacing is roughly 18″ to 24″. Step-4: Rebar Calculation Process Of The Slab Panel-A 4. Next, divide the total square footage by the size of the rebar. Generally, rebar is Grade 32 and utilized for 3-inch slabs. Place concrete at a minimum thickness of 4 inches. That way you can use the forms themselves as a guide for the final base height. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required. 2. Additionally, any slab poured over 4 inches should also be bonded with mesh fabric to the 2 preceding layers of clear of construction joint material to ensure the slab is adequately supported. A 4 – inch -thick slab cast on the ground and in permanent contact with it will float and rebar is not required. What is the minimum reinforcement in slab? 2- Slab Reinforcement Details. e. In other words, for a 4-inch slab, space the joints 8 to 12 feet apart. 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. Thick slabs Thick slabs are concrete slabs with an overall thickness of 4-6" or greater and can be either grade level (slab on grade) or below grade (i. Concrete Thickness. slabs, walls, and joists - #14 and #18 bars - ½ inch; Slabs, walls, and joists - #11 bars and smaller - ¾ inch ; Beams and columns - 1½ inches ; 2. Thickness of concrete slab depends on loads and size of the slab. For one layer of 6x6 W1. 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. We would like to show you a description here but the site won’t allow us. into an existing footer with a min. The dowels will then be embedded in the ICF wall concrete. The design of one-way slab is simple and can be carried out easily. This video series w. Table 1-Minimum Shrinkage and Temperature Reinforcement steel for non-SES floors or SES floors with a secondary liner. longitudinal and transverse. 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. Above 12 1/4” they have a single cover height per chair. When spacing the rebar, it is important to ensure it is evenly distributed and in accordance with the local building codes. 72 percent. No, you do not need rebar for a 4-inch slab of concrete on grade. 6 bars and bigger – 2 inches. In some cases, concrete needs reinforcement with steel mesh. 1%. For example, the percentage of reinforcement of a 30-inch slab with two layers of No. #5 bars are 5/8”. 5” to 12”. Workmanship and jobsite conditions. No, you do not need rebar for a 4-inch slab of concrete on grade. Compare that to the tensile strength of Grade 60 rebar, which is 60,000 psi. . Designed for #4 and #5 rebar,. Vertical placement tolerance for reinforcement in slabs-on-ground is ± 3/4 inch from the specified location. For a 4" slab on grade house, what would you say about #3 vs #4 rebar, and the spacing? I was going to do #4 at 12" - Answered by a verified Structural Engineer. Every concrete slab should have a minimum. Anchor bolts are located a minimum of 15 anchor diameters from the edge of the concrete perpendicular to the length of the wood sill plate. 5. /18 in. _____ Bar Supports Bar supports are required in a number of locations on bridges. 2. Unique fastening system ensures accurate positioning of rebar, to code, during concrete placement. B3030. Once you input these values, you will have your grid length dimensions, it’s that easy. Position a rebar grid or 4. of Engineers (Army TM 5-809-12) that you can download for free from thier website. For driveways and patios, #4 (1/2 inch diameter) rebar is a common choice. If the slab is going to support extra weight, such as the weight of a vehicle or the weight of the soil for a retaining wall, then stronger rebar such as #5 (5/8-inch diameter) or #6 (3/4-inch diameter) might be. For garage slabs, two rows of #4 rebar are recommended around the perimeter, one above the other. 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. Re: rebar dowel size and spacing. Divide 27 cubic feet of concrete in a cubic yard by the volume of the concrete bag. of Main bars = 20 + 1 = 21 Nos. 78 kg/m 3) in accordance with the manufacturer’s recommendations. #4 is 4/8”, or 1/2”. Do You Need Rebar For A 4 Inch Driveway Slab? A 4 inch concrete driveway slab is too thin for rebar. 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. Why is rebar spacing crucial?11. When you build a 4-inch slab, you’ll need a higher grade of rebar. A 4-inch concrete slab with a 2-inch road base and #3 rebar at 16-inch spacing can provide a reasonably strong foundation for a patio structure such as a patio cover or gazebo. area = 25′ × 25′. To calculate Total Area of a multi sided slab, first divide the shape into rectangles or squares. 7 mm). 9. The proper way to use rebar reinforcement is to ensure that it is laid in the center or slightly above the center of the slab's thickness. Its rebar size in inches is 0. 2. e. Rebar Chair is a patented polypropylene support system ideal for concrete applications requiring a 6 in. 08 cubic yards for one concrete tube; Multiply 0. Add 5%-10% additional material for some waste or spills. The grade shall be as specified by the. 4/1. However, many engineers and. Put the mesh on wire supports, sold separately, so it sits roughly in the middle of the slab’s thickness. See Figures 3-6. 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. In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design. 0 inches use 4 inch Schedule 40 PVC duct and internal joining coupling for 4 inch I. It create a bending of the slab. 4/1. 1. anchor bolts and the 4 inches (102 mm) φ pipes. 3: Minimum 8mmdia rebar is required for slab construction. Spacing of bar supports depends upon the size of the reinforcing bar being supported. Sawcut Joints. My driveway is 4 inch thick concrete. The bar size in English units is roughly its diameter, in eights of an inch: a #8 bar has a one inch diameter. Minimum concrete cover over (and to the sides) of the reinforcing bars is 1 1/2-inches, whereas the minimum concrete cover under the rebar is 3-inches. The installation of the rebar is critical for the success of the overall project. The rebar needs to be correctly. 5x the maximum aggregate size. Build forms. 4 wire mesh in a 4-inch slab, P = 8. 2. Stocked in half inch increments between 6. Reading time: 4 minutes. 11-22-2006, 08:16 PM. If the slab is thicker, then re-bar should be used. As per the present market rates, the average cost of concrete for a 400-square foot slab, the typical size for a two-car garage, ranges between $583 and $637 or between $1. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. 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:. 33_2_0. They cannot hold a load factor. 10. Proper and even spacing is also important. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. 5 inches up to 12 inches. Tying should include bars near the ends of the bridge and bars near the curbs. I will drill with a hammer drill and a 3/8 bit through the expansion material and into the existing slab about 6 inches. The appropriate rebar size depends on the project, with #3 and #4 being common choices. Horizontal rebar is. View More. It has a procedure for using rebar to reduce slab thickness, and if I remember right for increasing joint spacing. _____ Bar Supports Bar supports are required in a number of locations on bridges. This space will be between the edge of the driveway concrete and the rebar. For example, a 4″ slab should have control joints placed a maximum of 12 feet apart. For a 400 square foot slab, the man hours required to finish a two-car concrete garage slab is about 13 hours. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required.