63 D. if you are pouring a concrete slab that is more than 5 inches in depth, you should install rebar or welded wire fabric to. In slabs with an average thickness of less than 6 inches, the spacing should be. 75)(8)sqrt(f [c)( slab thickness. 16000 lbs divided by 144 is 111 pounds per square inch. 5, 5. yds. 59 per square foot. The evaluation of rebar spacing results shows that the maximum standard deviation for rebar spacing is 0. Total Cut Length = 3,120" or 260'. (inches) Enter a waste factor, if required. Rebar reinforcing requirements are influenced by the concrete’s composition and planned application. 11 in. (inches) Enter the required splice (overlap) of your bars. Input all the dimensions in the input section of the above calculator. It has stood up to some really heavy equipment for 25 years. Do you need rebar for 4 inch slab? No, you do not need rebar for a 4 – inch slab of concrete on grade. and 5. Reinforcing Steel Check List Abutment Footingand not less than 5. 3, No. runs of rebar 2 feet apart and rebar size 1/2 inch or 5/8 inch. This is so the edges can be formed by using a 2×4 and the area to be prepared can be graded off the same. 4@24" - the first number ‘4’ is the rebar size, the second number ‘24’ is the on center spacing of the bar placement in inches. Unless. 415-5. My understanding of slabs based on limited experience and a heck of a lot of reading here is:1. Cover the fill with a layer of 6-mm plastic sheeting. The minimum spacing of rebar in slabs varies depending on the application, with typical spacing distances between 5 and 6 inches on center. 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. You’ll find that #3, #4, and #5 size rebar is most commonly found in home reno stores and used in footings for homes and other domestic structures. Imposed loads varies from approximately 1. arrow_right. reinforcing parallel to load per inch of slab width perpendicular to load / slab thickness) (steel yield stress)) f c LE 100psi ; V n limited to (0. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. Adding fiberglass to the concrete is even better and is almost standard practice now. Every concrete slab should have a minimum. 17 inches (18" controls) #3 bar = 10. with a maximum rebar spacing of say 12" to 16" to keep the crack widths small. CHAPTER 23 WOOD. See Figure R611. Size and spacing – for example #3s @ 6” O. The string will act as a guide to keep the form boards straight. The coefficient β 1 ranges from 0. There are three different sizes of rebar typically used for home construction projects. Rebar Placement in Walls. , or 4 in. For masonry or concrete construction, the minimum foundation wall will be 6 inches. 64 mm) between longitudinal rebar 2 and 3, which is the same as the rebar construction and traditional tape measurement results. thick slab, the maximum joint spacing should be. SECTION 1908 SHOTCRETE. 6 to 58. Reinforcing bar size to be not less than #4. The concrete’s tensile strength can be reduced by 20 percent even if there is an inch extra in spacing. Grade of steel;Size and spacing of the steel reinforcing; and. immediately behind the wall. 00 H x 0. Select the unit of dimension like meter, feet inch, etc. arrow_right. for 10 000 lb axle load on a 6” slab with dowel spacing at 24” on center). SECTION 1907 MINIMUM SLAB PROVISIONS. ) Elevated slabs on metal deck. 75 inch is typical for slabs, and for concrete cast against soil, 3 inch minimum is required. For 0. INSTRUCTIONS: Choose units and enter the following:. Reise 082018. If the slab in question is just for a patio or a similar purpose, #3 rebar with a diameter of 3/8-inch will do just fine. 20 per square foot on average. For slabs up to four inches thick, rebar should be spaced between 12 and 18 inches apart. Stretch a string between two screws installed at the edge of both ends of the form boards. Alternative to Welded wire Mesh. 2The most common steel reinforcement or rebar sizes in residential construction are No. Labor Costs. Dia of Bar to be provided 'd' = 16 mm (round bar) Area of cross-section of 1 bar = 0. Minimum reinforcement is 0. Select Rebar Size: Enter WWR Yield Strength: Bar Spacing (in) Bar A, per linear foot Rebar Weight per 100 SF (lbs) WWR as per linear foot WWR weight per 100 SF (lbs) Required Wire Size Corresponding to Spacing (in inches) Noted. 65 for fc ' ≥ 8000 psi (Figure 5. This occurs most often when the required cover is over 2. 5" with the minimum being 7. If you need to cut concrete to specific. 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. Properly compacted sub-grades can reduce needs for reinforcement – as well. If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. 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. 40 to $6. For slabs. For example, control joints should be 15 feet apart on an 8-inch slab, but only 10 to 12 feet apart on a 5-inch slab. Rebar needs to be kept at least 2 to 3 inches from the slabs surface on the top, bottom and all sides. Still, many. New concrete slabs must conform to the above stated properties before. Check for level on all sides. Click on Calculate button to get the total weight of the steel rod in the slab. A good compacted base below the concrete is equally important. 5 inches. In such applications, using size 3 and 4 rebar is common. Therefore, it must be placed properly and evenly. Minimum bar spacings are specified to allow proper consolidation of concrete around the reinforcement. Thickening the structure along the perimeter by another will serve as an integral footing, adding strength where the loads are. What size rebar should be used on a 4 slab? If you want to make a driveway or patio, you should use a #3 rebar which is 3/8 inch in diameter. Splices 25. Proper control of joint spacing and sealing is important. SECTION R403 FOOTINGS. And rebar is sized by eights of an inch. ' = 1536 sq mm. The versatile Mesh-Up is available in four sizes:*. I use a 5 inch rebar for building footings. (#5 bars) may be required, or the spacing between the bars should be reduced. Following the process, you can easily calculate the quantity of steel required for any type of slab. 500 kg/m2 is. The ideal rebar spacing for a concrete slab should be around a foot and a half in length. As the number of the rebar. Answer: Depends on your usage. 4mm (6-1/4 inch) slab provides a 3-hour fire rating. 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. 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. Joint types and usage. For concrete cast against and permanently exposed to earth (such as footings) - 3 inches; For concrete exposed to weather or earth (such as basement walls) #6 bars and larger - 2 inches #5 bars or smaller - 1½ inches; For concrete not exposed to weather or in contact with the ground: slabs, walls, and joists - #14 and #18 bars - ½ inchThe concrete slab should be four inches thick at least; it needs to be thicker if heavy equipment will rest on it. #4 bar = 18. FIrst, find number of rods required for main reinforcement and distribution. 5. For a 121. 5 times the slab thickness in inches. The spacing is highly dependent on the concrete mix's shrinkage potential. 75-in x 10-in x 5. 5 cm) centers the other. 5 in ACI 330 • Note that spacing never exceeds 15 feet Pavement Thickness, in. When spacing the rebar, it is important to ensure it is evenly distributed and in accordance with the local building codes. But if the slab is for patio or bridge, you can use the #3 rebar. 8 mm) Sustainability 2021, 13, x FOR PEER REVIEW 3 of 17 . 2)(12 in. ( LF) Lapping Factor. Though Mesh-Ups can accommodate a variety of different types of remesh, cables and wires, the plastic. Number 3 rebar is meant for driveways and patios, number four is for walls and columns, while number 5 is meant for footers and foundations. (ii) The maximum spacing between two secondary parallel bars shall be 5dor. #5 bars or smaller: 1½ inches. #4 Rebar ; The #4 rebar is often used in residential and commercial projects to add strength in slabs and columns. Reinforcing bars are placed in a concrete member with a minimum concrete cover to protect it from weather, fire, and other effects. 7 m) with rebars at 8 inch (20. Two way-slab ThicknessA single rebar mat is only going to hold the slab together when it cracks. 4,5 or 6, second number, in inches, is vertical on center spacing 2. Dynamic and/or oscillatory. When a = 3. The Total Grid Rebar Length calculator computes the total length of rebar needed for one or more mats of rebar in a concrete slab. 1907. See more. 2. (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. Using the search function should turn up a lot of info. The Weight of Rebar in a Slab calculator computes the total weight Concrete Slab with one Rebar Grid mat of reinforcement bars (rebar) needed for a concrete slab based on the dimensions of the slab and the spacing and size of the rebar. arrow_right. A 4-inch-thick slab cast on the ground and in permanent contact with it will float and rebar is not required . it is mandatory for rebars to be surrounded by concrete. 7 mm). Keep in mind that if fiber is only used, the subgrade must be properly compacted and prepared in accordance with the geotechnical engineer’s recommendations. For instance, the ACI 318-19 specifies minimum slab thickness that satisfies deflection. 668 lbs/ft with a cross-sectional area of 0. coverage = 250 sq ft. Step 2Table 5-5: Minimum Clear Cover for Drilled Shafts on Bridges Drilled Shaft Diameter, D (ft. The diameter of bar generally used in slabs are: 6 mm, 8 mm, 10 mm, 12mm and 16mm. I will drill with a hammer drill and a 3/8 bit through the expansion material and into the existing slab about 6 inches. 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. 4(1). ¹Owens Corning PINKBAR®+ Fiberglas™ Rebar currently holds ICC-ES approval as an ASTM D7957 compliant material. 6. 12. 5, which correspond to diameters of 3/8-inch, 1/2-inch, and 5/8-inch, respectively. 1 Supports: 1. Vib ratory loads. Around here we typically do 4 -5 inch slabs for driveways with rebar at least every 2 feet on center and some go more or use wire mesh. Place rebar in a grid pattern with a spacing between bars of approximately 12 inches . By Concrete Construction Staff. For wheel (or post) spacings of 5' to 15', the increase in stress isThe rebar used for swimming pool construction is grade 40 deformed bars conforming to the standard of ASTM A615. 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. Joint spacing that is greater than 15 feet require the use of load transfer devices (dowels or diamond plates). the maximum size coarse aggregate should not be less than 3 inches c. 7 m) by 12 feet (3. New concrete slabs must conform to the above. 3) Steel required for 1 sq ft slab 6 inch :- area of RCC slab is equal to 1 square feet and thickness of RCC slab 6 inch,then volume of concrete it is calculated by multiplying area and thickness of slab. Divide your result by the spacing measurement: 180 / 14 = 12. 6. ) Structural slabs-on-grade (mats) 4. ½ inch Diameter Anchor Bolth Spacing (inches) a; 8'0" 7'4" GW,GP,SW,SP GM,GC,SM-CS,ML SC,MH,ML-CL,ICL: 30: 245: 72: 45: 370: 72: 60: 490: 48: 9'0". ) Elevated cast-in-place slabs. Divide your result by the spacing measurement: 180 / 14 = 12. 1 for details. I've only ever called out a single layer in a 8" s-o-g. Spacing is critical, because grids that are off by just one inch can reduce the overall strength of the concrete by 20 percent. 3. The minimum reinforced concrete footing thickness will be 6 inches or 1-1/2 times the length of the footing projection from the foundation wall, whichever is greater. Great for use when pouring concrete slabs. Do You Need Rebar For A 4 Inch Driveway Slab? A 4 inch concrete driveway slab is too thin for rebar. 9. Vertical placement tolerance for reinforcement in slabs-on-ground is ± 3/4 inch from the specified location. 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. 70456 2-3/4" X 5' 0. For 6" to 10" thick slabs on grade with 'k' values between 100 pci and 200 pci, the increase in stress, 'i', due to a 2nd wheel (or post) load as a percentage of stress for a single wheel (or post) load is approximately 15% to 20% for a wheel (or post) spacing of 3' to 4'. 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. Concrete StrengthThe Rebar in a Circular Shaped Slab calculator estimates the total length and weight of reinforcement bars (rebar) needed for a circular shaped concrete slab. B3030. β = Ratio of clear span in long direct ion to clear span in short direction αm = Average value of α for all beams on edges of panel. arrow_right. 2. arrow_right. Click HERE for spec sheet. Grade. Guidance for joint spacing to minimize out-of-joint. 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. (as in example diagram)There's no generally-accepted rule of thumb as to how to space rebar in a concrete slab. 75-in 40-Pack Polypropylene Rebar Chair. Wire mesh or thick reinforcement bars ("rebar") has long been a component of concrete slabs. The appropriate rebar spacing for most of the slabbing is 12-inches. the maximum size coarse aggregate should be more than 6 inches. Tips for pouring stronger, crack-free concrete slabs. 5” to 12”. For example, if the percentage is 0. Why Rebar Spacing is Crucial. ) (12 in. 4(1) Page 3 of 4 Figure 4: Wall/Footing connection TECHNICAL BULLETIN No. As well as that, the calculator will also tell you. #5 or 5/8” diameter slabs may be used for residential slabs that bear heavy weights. 5 pounds per square foot, the maximum allowable weight. REBAR SPACING: GP‐7 SERIES MODELS: 4‐1/​4" 3000 PSI / 28 Day Aging #6 Rebar: 12 in:. For Greece, the maximum aggregate grains dimension for usual concrete, is 32 mm and for self. arrow_right. . Area of Steel 'Ast req. 5-0. . 4. One common problem is chairs getting tipped over during the pour. 33. Stocked in half inch increments between 6. New concrete slabs must conform to the above stated properties before installation of. R611. For example, an expansion joint in a sidewalk may only. In bonded system, the topping is adhered to the underlying concrete slab. 042 square inches per foot of slab width, required each way. (ii) one-third the depth of slabs. Rule #5: For better crack control keep the maximum distance between joints in feet at 2 to 2. for bothFor indoor exposure, 1. 5" Rebar Chair (911) 3" Rebar Chair (912) 2-Bar Footer Stand (928) 3-Bar Footer Stand (924) 2" Steel Mesh Chair (944) EstimatorShake out the rebar. The maximum diameter of bar used in slab should not exceed 1/8 of the total thickness of slab. 24). rebar size, rebar spacing, rebar grade and concrete strength. If the concrete slab in question is meant to be the footing of a house, then #5 rebar with a. 0 inches. Input the number of mesh in slab rebar. Instead of “placing” or inserting the rebar during a concrete pour, the rebar is prepared at the proper location and height, then the concrete is poured under, around, and over the rebar to embed it in the slab. 5, shotcrete shall conform to coarse aggregate grading No. 87 d Spacing of bar = Design of Continuous Slab Suppose a slab is supported at the ends and also at intermediate points on. 1907. This type of. . Generally, rebar spacing in slab footings ranges from 12 to 24 inches, both for horizontal and vertical bars. Use 2” rebar chairs to support the rebar in the center strata of the pad. Slabs, walls/dividers, and joists – 11 bars and littler – ¾ inch. Minimum Foundation Wall and Wall Footing Thickness. 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. 5; 12. Coarse aggregate, if used, shall not exceed 3 / 4 inch (19. It assumed in this calculator that they are the same. ) NOTE: Also available in metric sizes. To be continued >. Grade 40 means that the yield strength is 40,000 psi and the code allowed strength is 20,000 psi. Maximum spacing 12 inches on center. Unique fastening system ensures accurate positioning of rebar, to code, during concrete placement. The rebar should form a neat grid. For the short side, 240 inches divided by 14 inches gives you 17 lengths of 20-foot rebar plus a bit left over. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. SECTION R406 FOUNDATION WATERPROOFING AND DAMPPROOFING. 1. 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. Much of your need for reinforcement will be dictated by how well your site was prepared. 5. the slab beyond the critical section for a required length. Bonded Topping Slab. Available Heights: 3” to 12-1/4” in 1/4” increments. If rebar spacing is 12" or less, place chair at every other rebar crossing. (i) The maximum spacing between two parallel main reinforcing bars shall be 3dor 300mm or whichever is less, and. But a 4″ thick slab really shouldn’t have rebar in it, too thin. 5-1. Please call (888) 488-9276 for more information. The rebar should form a neat grid. Calculate the amount of rebar reinforcement needed for slabs and drive ways. and serve as guides for reinforcing bar spacing n Available in plain, epoxy or galvanize coatings. 375 inches, the spacing should be at least 1. Load capacity of simply supported concrete slabs. However, it is better if 10mm or 12mm diarebar can be used with spacing of 100-125mm (4-5’’) between rebar. 5" Rebar Chair (911) 3" Rebar Chair (912) 2-Bar Footer Stand (928) 3-Bar Footer Stand (924) 2" Steel Mesh Chair (944) EstimatorIt is better to use #5 rebar size for footers and foundations. A four-inch slab, for example, can cost anything from $0. For optimum performance, rebar should be inserted in the middle or slightly above the center of the concrete slab. The minimum concrete strength is 3,500-pounds-per-square-inch. 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. Rebar Spacing; D2-8F: 4. 375/2 = 21. (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. Space joints (in feet) no more than 2-3 times the slab thickness (in inches). And a cross-sectional area of 0. F ree Design Assistance ProgramAdd rebar for reinforcement, Ralston places rebar every 16” on center. This translates to roughly 5/8 inch rebar and must be spaced equally along the slab to create a proper grid. 3 cm) centers in one direction, and 12 inch (30. Hence, in the above given example spacing for 16 mm dia bar has been calculated, thus. 403. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. We would like to show you a description here but the site won’t allow us. 25" 3,000 PSI / 28 Day Aging #6 Rebar:. We would like to show you a description here but the site won’t allow us. You can multiply the bar size by 1/8 to get the nominal diameter in inches. PINKBAR® Fiberglas™ #3 Rebar is 3/8-inch diameter x 20 feet long. Additionally, rebar needs to be inspected to ensure the placement is in the middle of the thickness, and steel diameter is correct prior to the pour. 5-7 Floor slab geometry. Product Details. 5 inches. 785 x 16^2 = 200. 15% for mild steel bars. Rebar Chair is a patented polypropylene support system ideal for concrete applications requiring a 6 in. Rebar or Reinforcing bar is a ribbed steel bar that is used in concrete slabs or in structures to strengthen a building. 030 Allowable deflection for lift truck traffic per ACI 360R-10 0. According to 26. We've seen metal key forming systems with knockouts for dowels advertised for 3- and 4-inch slabs, but we. 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%. Raise the form sides 1/2-inch to create a slab that is a full 4 inches thick. For example, let’s find the number of 5′ x 50′ rolls of mesh required to reinforce a slab that is 25′ by 25′. Spacing required = Area of 1 bar x 1000 / (Ast req. Goo. (as in example diagram) Multiply the 2. In order to calculate this, you need to input the length and width of your slab. #3 rebar @ 24" o/c for a 4" residential slab and #4 rebar @ 24" o/c for a 5" or 6. 2018 Fo Blocs. 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. For an unreinforced slab, control joints should be spaced in feet 2 to 3 times the slab thickness in inches. 376 lbs/ft or 0. Originally Answered: Do you need rebar for 4 inch slab? Reinforcement can be either wire mesh or ½- inch (#4) steel rebar. When using #4 rebar for a 6-inch slab, standard practice is to have 1 piece. Blocks should be utilized beneath the reinforcement in either situation to keep it centered in the concrete. When spacing is closer together, the amount of concrete cover over the bars should also be taken into consideration. 2. 23a. Leave the steel out and make the slabs an inch thicker. Then add 10 percent to allow for spillage and slab depth variations to help determine the concrete cost per yard. (Designed to receive 6, 8 or 10 gauge wire. The minimum spacing is the maximum of 1 in, a bar diameter, or 1. A-9 Figure A. ) * (Additional chair can accommodate 4 and 0 gauge wire. 0 mm) Packaging Requirements: Slab bolsters and other continuous rebar supports may be specified, quoted, and purchased by the linear foot or by the unit (each). Using the rebar tying tool, twist wires around the intersections of the bars. One Way Slab Bar Bending Schedule Calculation. Reply. 33 ft² @ 8" thick. In other words, for a 4-inch slab, space the joints 8 to 12 feet apart. Concrete Thickness. 2 in accordance with Table 1. For example, for a # 3 bar, which has a diameter of 0. Place the holes at the 2. The ACI 318-19 provides a number of requirements regarding slab thickness, concrete cover, and reinforcement ratio which facilitate the design process. Weepholes should have a minimum diameter so as to permit free drainage. Clearance from steel to earth, usually 3” for concrete or shotcrete cast directly against earth. 5 48-foot joint spacing. For best results, rebar is generally located at the center or slightly above the center of a concrete slab. . 2-inch chairs at the sup-p o r ts for a 31⁄ 2-inch slab; 2-inch chairs for a 4-inch slab; 21⁄ 2- i n c h chairs for a 41⁄ 2-inch slab and 3-inch chairs for a 5-inch slab. A 4" slab should have joints 8-12 feet apart. How critical would this difference in elevation be with respect to the spacing between rebars? A. 2. When putting rebar into walls and columns, the bars should typically be spaced at least 6 inches apart to provide adequate reinforcement. Swimming Pool: The minimum rebar sized to be used for a residential swimming. 7: Garage footers must be 24 inches deep, size of framing for footer is 6 inches deep X 16 inches wide, with 2 runs of rebar size 1/2 inch or 5/8 inch. Shared Use Path Panel Size5/8" x 20' Rebar Grade 60 (#5) Model Number: 1831139. No, you do not need rebar for a 4-inch slab of concrete on grade. 8 200,000 36 9 y n f l h β ⎛⎞ ⎜⎟+ = ⎝⎠ + Eq. Concrete cutting calculator block dimensions plan view diagram. The typical depth for rebar placement for slabs is 2-4 inches. 2 shows, the slab with only 2 inches of concrete cover between dowel and surface performed as well as the slab with 3 inches of cover for up to 10 million load cycles (Odden et al. PSD12/#5TX 3/4“ Smooth or #5 Rebar X 24“ 12“. The spacing of the weld wire mat may vary from 6 inches to 18 inches. No sawcut contraction joints are used longitudinally. The ends of the bars should be two or three inches from the sides of the form to protect the rebar from the elements. 12% for HYSD bars and 0. 503-2. #4 rebar is perfect for adding strength to highways and can give columns and slabs added strength. Lastly, slab thicknesses are usually rounded off to the nearest 10mm. Generally, rebar has an immense impact on concrete. While this is most likely a private application, most bridge deck slabs are 8. 4, 4. CHAPTER 25 GYPSUM BOARD, GYPSUM. Maximum Spacing,ft. First, find the area of the slab. : In ACI 302. If rebar spacing is 12" or less, place chair at every other rebar crossing. The spacing of the rebar is also determined by the weight and size of the slab. If you are constructing walls, piers or columns, I recommend the use of a small piece of reinforcement. The length = 8′-5″ or 8. 3 Tying: Tie all intersecting bars with a double-strand single tie. See Figure 5. PSI means per square inch. 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. 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. 5000 PSI concrete can safely support 5000 pounds per square inch (PSI) minimum before its compressive strength is overcome. 5*(spacing between bars). coverage = 5′ × 50′. The maximum limit on. I was going to provide a 10" by 10" thickened edge around the perimeter of the slab, with the bottom of the thickened edge tapering into the 5" typical slab. 0, the thickness shall not be less than 0. Loop the tubing in any convenient pattern, maintaining the proper spacing. Assuming suitable bearings (not less than 10cm), find the span of the slab between the centers of bearings. Calculate the volume you need in cubic yards. The chairs may be made of metal or plastic or other non-corrosive material. 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. If the reinforcing bars do not extend beyond the critical section sufficiently, they will be pulled out and the structure will fail.