Calculating rebar for concrete slab. The amount of rebar needed for a slab will depend on the size of the slab and the particular requirements of the project. Calculating rebar for concrete slab

 
The amount of rebar needed for a slab will depend on the size of the slab and the particular requirements of the projectCalculating rebar for concrete slab <b>bals eht fo egde eht morf yawa dna bals eht nihtiw tis ot sdeen raber ehT </b>

area = 625 sq ft. . Stretch a string between two screws installed at the edge of both ends of the form boards. I am looking for information to calculate what is my required dowel rebar size and embedment length to dowel into a reinforced concrete slab? I know ACI has provisions for doweling a concrete column/pedestal into a footing, but I am trying to find something regarding doweling CMU rebar into a concrete slab. The user must enter the strengths of the concrete and the reinforcement, the unit weight of concrete, strength reduction factor for lightweight concrete, beam dimensions and slab. 5. Enter your length, width, and thickness then hit calculate and you'll see how many cubic yards you need. Quantity Estimate for Reinforcement in Kg: Quantity Estimation of Reinforcement in Kg. The calculation of concrete cover takes into account the requirements for structural performance, fire resistance, and durability. First, grab a few 2 x 4’s and use the lumber to measure out and frame the area to your desired slab size (whatever best fits your space and needs). Enhancement of the strength of the. To calculate Total Area of a multi sided slab, first divide the shape into rectangles or squares. Multiply the length (10 ft. 004, the strength reduction factor of ACI 318 Sec. To figure out how much concrete you need to buy, you simply need to multiply the volume required by the density of the concrete mixture. 3269 kg. 2 kg. ( i) Inset distance from the side of the slab to the rebar grid (default of 3″). Where you are pouring the concrete will be your slab. The steel working stress must be great enough to. Where ‘D’ and ‘L’ are the diameter and the length of the rebar respectively. Rebar - Slab, Driveway or Patio. Convert your longitude estimation into inches: 15 x 12 = 180. Click the button to calculate the volume of concrete and man-hours (not including mixing) needed for this job. Determine the Pad's Area. 0009fy - 24)d; [ For fy > 60,000 psi] The minimum lap length for compression bars must be 12inches. or ACI 318M-11 Equation 12-1. 062*fc'(0. Calculation of concrete cover for bond The minimum cover for bond c min,b is calculated in accordance with EN1992-1-1 §4. 3. 075kN m. g. Overlap joint for rebar connections of slabs and beams and overlap joint at a . Total rebar weight 53. splices) or global compression struts to avoid brittle. 33_6_0. compensating concrete demands the use of reinforcing steel so the concrete can expand and con-tract as planned. Concrete slabs that will hold a heavy load or be built on soil in poor condition could require steel rebar reinforcements. In simple, it is a concrete block provided to create the cover between the reinforcement bar and the concrete surface. Cost of Rebar: Provides the cost of rebar on a project. Plain and untreated steel rebar costs $0. Therefore, #2 rebar is ⅛” + ⅛” = ¼” in diameter. 1 provides expressions for determining. 3. After finding the overall thickness of the slab, compute the volume to determine how many bags of concrete you need for a given slab. For example, if you are using ½ inch rebar, divide 60 feet by 0. The Rebar in a Circular Shaped Slab calculator estimates the total length and weight of reinforcement bars (rebar) needed for a circular shaped concrete slab. ( D) Depth of slab. Number of cubic yards = 64 cubic feet ÷ 27. Click the button to calculate the volume of concrete and man-hours (not including mixing) needed for this job. 12. The Rebar Calculator contains equations and data used in working with reinforcement bars (rebar) in concrete slabs. 2. D. It is used mostly in a combination of these two in concrete slabs. Weight (lbs/ft) = (Diameter^2 / 162. 5 CY for Site A and 21. According to this method, you will need two rebars for a footing width of 16 inches, four rebars for a footing width of 24 inches, and so on. = 565. This calculator finds rebar sizes and spacing for beams, girders, and 1-way slabs for a particular type of reinforced concrete floor system consisting of a regular grid of columns supporting a hierarchical. This resulting number is the area ("A") in square feet of the concrete pad: A = L1*L2. g. justcalc. The net result is a more accurate and less. For compatibility with older ACI codes, Ψr is taken as 1. In. This will allow you to calculate the square footage of the slab. So you will want to take note of the slab length and width. Specify the spacings: rebar-rebar spacing = 40 cm, edge-grid spacing = 8 cm. A rebar slab calculator is a tool used to determine the quantity and spacing of reinforcing bars (rebars) needed in a concrete slab. 25L 2, whichever is less. that is 2. Re-do Example 1 Re-do Example 2 Calculating the Weight of complicated Objects – Using Weight per Foot Method There is a very simple way to calculate. The exact distance from the reinforced concrete slab’s edge to the rebar should depend on the specific application, size, and thickness of the slab. Some regulations specify how much rebar is required to be poured into concrete. Multiply the measurements together to calculate the square footage of the area. GEGCalculators. Input length, width and depth of the area. Once this is complete, you will need to add the steel reinforcement bars (or similar) by clicking the "Add/Edit Steel Reinforcement. Rebar and Slab Calculators: Find how much concrete weighs by entering the. It is generally accepted that rebar should have minimum 6″ clear cover from all edges, corners, and other forms of reinforcement. No. 3 cubic feet of concrete for this slab. 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. 2. Like our other calculators, this reinforced concrete Beam Capacity Calculator is very easy to use. Mass / Volume Conversion. Building a concrete slab foundation costs $5 to $14 per square foot or $4,000 to $33,600 total on average. Concrete is ordered by volume in cubic yards. The pavement slab directldesign method consists of determining thy e opposite the mismatched joint should be reinforced percentage of steel required, the thickness of the with a minimum of 0. How to calculate Reinforcement Ratio in Concrete || Percentage of Steel in Structural Member by CE&TSubscribe this channel for latest and update videosPlzHel. A s,max = 0. 3 of ACI 318. ACI 318-05, Section 11. Equate the balanced moment of resistance to the maximum bending moment; Find the effective depth ‘d’. 05 percent of steel ireinforced concrete pavement, and the minimun m directions normal to each other for a distance of 3 allowable length of the slabs. 19 c rc c c ' c '. Next, find the coverage of the roll. U. 28084 feet Rebar calculator for slab helps you find the total weight of steel rod required to construct the. A base of gravel will help prevent erosion and keep the slab from settling. Slab concrete properties definition before design optimization. 87 d Spacing of bar = In this article, a method is proposed for calculating the reinforcement of concrete ceiling slabs with carbon composite materials based on the finite element model in the computer program SCAD. ( RL) Length of the pre-cut rebar sticks being used to. of bars = { (L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8 where L or W: length or width of footing. The PT Calculator is ideal for owners, developers, contractors, architects, and engineers who need to quickly estimate quantities and concrete sizes. Rebar Weights: The table below is based on a 10 % lap and works with any diameter rebar. Our calculator will instantly calculate the quantity of rebar required. are needed for a slab or concrete cores, and a quick and easy connection to get a quote on rebar, mesh, or other concrete supplies. Rebar is a key part of reinforcing concrete and ensuring a strong and durable structure. On average are required, for 100 square feet with 5 inches thick slab, 19 strips of 3/8” rods (30 ft each one), are 570 ft. Rebar Lapping Length: Computes the length overlap needed at rebar joints based on the size of the rebar. 5 = 158. 56% and Equation b) for λ= 1 and ρ w > 1. Column strip includes beams if any. 40X13. They seem to have that. The effective compressive strength of a column increases as it is confined by the slab, and the. e. e ve r y type of concrete construction that will be encoun-t e r ed on residential, commercial and industrial build-ing including form s , re i n f o r cing steel, and concre t e placement. This is achieved through techniques such as spraying concrete slabs with compounds that create a film over the concrete that retains water, as well as ponding, where concrete is submerged in water and wrapped in plastic. 84 m; grid. For slabs of septic tanks, you usually use #3 and #4 bars. For example, if the length is 10 feet and the width is 8 feet, the area would be 10 x 8 = 80 square feet. Rebar is. Rebar one rod weight is 5. Based on this average cost, a 10x10 concrete slab will cost $821, a 20x20 concrete slab will cost $3,284, and a 30x30 concrete slab. The finite element method is commonly used to design the reinforcement in concrete slabs. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. Enjoy the Rebar Calculator for Slab. Rebar, or reinforcing bar, is used in many masonry and concrete projects to reinforce slabs and structures. 2 CY for Site B when taken to the tenth of a cubic yard (0. The weight of rebar can be easily calculated by using this standard formula mentioned below: W= (D2/162. The following factors have the biggest impact on cost. 4. 4. 1. For example, if the percentage is 0. Note that this calculation is the volume of your tubes only and does not account for any overflow. Take the value of diameter in terms of millimeter and length in terms of meters. 25L 1 or 0. Hand calculation according to AS3600 Standard. The use of this calculator depends on the maximum length you can get your bars. (feet + inches) Enter the grid spacing. As such, I would do one of two things: 1) Effectively lap the rebar with the rebar in the elements above and below. 12. utilizing FRC include ground supported slabs, composite metal deck, pile supported slabs, mat slabs, pavements, bridge decks, tunnel segments, shotcrete, and various precast applications. Minimum dimensions and axis distances for reinforced concrete slabs. 5" Rebar Chair (911) 3" Rebar Chair (912) 2-Bar Footer Stand (928) 3-Bar Footer Stand (924) 2" Steel Mesh Chair (944) Find It Quick. For the design of slabs-on-ground with fiber reinforcement, Chapter 11 in the American Concrete Institute’s (ACI) 360R guide provides detailed information and calculations. First, find the area of the slab. 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. 5(alternate) and 5. The latest round of changes concentrates heavily on responding to developments in materials, structural systems and seismic design. Retaining Walls: The most commonly used rebars in retaining walls are #3, #4 and #5. The registered design professional shall assign nonstructural concrete a freeze-thaw exposure class, as defined in ACI 318, based on the anticipated exposure of nonstructural concrete. 45 cubic feet. g. . In this section, we will calculate the required reinforced steel rebar using the reference of the Australian Standard. The most common lengths of pre-cut rebar in the United States are 20`, 40' and 60'. The effective depth d of two way slabs can also be assumed using cl. If you’re wondering how many bar chairs you need per m2 for a sheet of mesh, generally, a minimum of 22 bar chairs per sheet of 6m x 2. The net result is a more accurate and less conservative estimate. Area. How much rebar is needed for concrete slab? Generally, one stick of rebar. Calculate the effective depth of the slab and calculate the concrete shear strength of the concrete slab. It ensures that you. Tying rebar at joints and positioning it in the middle of the slab is essential for proper reinforcement. Quick tip; Bar chairs are commonly sold in bags of 100, therefore, ensure you round up to the nearest hundred. Conversion. Most concrete slabs are cast monolithically with supporting beams, with portions of the slab participating in flexural resistance of the beams. 4 wire mesh in a 4-inch slab, P = 8. First, add up the total length of rebar you need. Maximum area of longitudinal reinforcement The maximum area of tension and compression reinforcement in reinforced concrete beams is;. From the above diagram, We can calculate the value of L. The type of and intended use of concrete impacts the need for rebar reinforcement. 5% of concrete volume, weight of steel required will be: =196. To find the Bar Bending Schedule for Slab we use the following formula, No. 5. 10m= 3m3. The Hercules Rebar Chair will help contractors increase profits by cutting cutting rebar placement time in half over wire typing. Reinforcing steel gives slabs on grade adequate strength at the joints. Calculate the steel quantity required in slab as 1% of volume of concrete 0. 01. 65*6) = 1. INSTRUCTIONS: Choose units and enter the following: Rebar Grid - One Mat (L) Length of Slab (W) Width of Slab (D) Depth of Slab (rS) Size of Rebar (none, 2-11,14,18) (i) Rebar Inset from the edge of the slab. Every concrete slab should have a minimum. In June 2023 the cost to Install Rebar Reinforcement starts at $1. ACI 318M-14 Equation 25. According to this method, you will need two rebars for a footing width of 16 inches, four rebars for a footing width of 24 inches, and so on. of Main bars = 20 + 1 = 21 Nos. 2—Design considerations Chapter 13—Design of slabs for refrigerated facilities. Post-Installed Reinforcing Bar Guide. Enter the slab dimensions, desired rebar spacing and the spacing from the edge to quickly find how to lay out the rebar grid. (Rebar Calculation Formula) No. In order to provide proper reinforcement that covers the slab evenly, rebar should be placed near the edges of the slab. area = 25′ × 25′. Next convert the 6" into a foot value by dividing this amount by 12. Besides the cost of concrete and materials, there are also labor costs. The user must enter the strengths of the concrete and the reinforcement, the unit weight of concrete, strength reduction factor for lightweight concrete, beam dimensions and slab. 2], even though the code permits. 2. The net result is a more accurate and less. When calculating V c, Equation a) for λ= 1 and a longitudinal reinforcement ratio ρ w < 1. 6 kg/m³. The Rebar Calculator contains equations and data used in working with reinforcement bars (rebar) in concrete slabs. The plate is 24 cm thick and is supported by 45/45/300 cm columns at distances of 6. For slabs = 1. To paraphrase the code: A Column strip is a design strip with a width on each side of a column centerline equal to 0. Pre-stressed concrete beam: 30 kg of tendon and 30 kg of normal rebar steel. Step 2: Calculate the area: Multiply the length by the width to find the area of the slab in square feet. Average: Rebar in Concrete Slab Estimator. ( D) Depth of slab. Access a comprehensive rebar weight chart. Click on Calculate button to get the total weight of the steel rod in the slab. When you swing on a rope swing and jump into a swimming hole, you exert tensile stress on the rope. 4 Shear strength of two-way slabs Loads applied to a relatively small area of slabs create shear stress perpendicular to the edge(s) of the area of load application. Find the number of concrete bags in the most popular sizes in the chart below: Bag Size. =7. 2. The Length and Weight of Rebar in Concrete Slab calculator computes the total length and weight of rebar needed for one or more mats of rebar in a concrete slab. For driveways and patios, #4 (1/2 inch diameter) rebar is a common. We typically ask our structural engineer for the weight of rebar is per sf (slabs) or volume of concrete for each mix/use. Building Supply Stores; Online Retailers; Wholesale Distributors. All of these. Estimation of steel reinforcement quantity is a necessary step in calculating cost of RCC structure along with other building materials as per. This calculator assumes that you are using 20 foot long lengths of Rebar. Divide the area number calculated in Step 3 by 5, as wire mesh in most commonly. There is two spacing between 3 reinforcement and 50 mm length both side of 1st and 3rd reinforcement used in footing. ls = (0. How could I calculate the reinforcement in these units given I know how much steel is in the slab in the other conventions I listed earlier?. 2. Calculate Rebar Quantity From Total Slab Area and Perimeter. the Android app here: the iPhone app here: calculator offers you a choice between five different types of concrete. 25 * 12. Measure the side that is the directly next to and perpendicular to the side measured in Step 1. If the load is greater, rebar spacing may need to be closer. The rebar is built in a grid structure and costs $2 to $3 per square foot. Step 3: Determine the thickness: Measure. When the dimensions of a slab, wall or other form exceed the length of a single stick of rebar, it is required to overlap and tie rebar pieces to create the added length. k. Sponsored LinksThe calculator estimates the number of rebar pieces needed for the slab. Effective depth d= Span / ( (L/d) Basic x modification factor) For obtaining modification factor, the percentage of steel for slab can be assumed from 0. The formula for the weight of a slab used in this calculator is: Wt = L•W•D•mD. 5^2 / 162. 005, which is equivalent to a maximum reinforcement ratio of 0. ( W) Width of the slab. xls", so called to reflect the use of the ACI 318-05 Code. CRSI’s Reinforced Concrete Concept is an online tool for preliminary slab design that provides design and construction teams with comparative evaluations and estimates for the most. 037 to get cubic yards of concrete. Calculate the main reinforcement per metre width; For M15 concrete, lever arm = 0. Common rebar sizes range from #3 to #6 for slab footings, with #4 being the most commonly used. 4. If you want to combine rods of two diameters, there would. Concrete and rebar must be used for every four feet of the foundation wall. 3—Steel fiber reinforcement Chapter 12—Structural slabs-on-ground supporting building code loads, p. When reinforcement bars of different sizes are bundled as compression bars, the lap length chosen must be larger of the following cases: Compression splice length of the least diameter bar or. Av,min=0. Maximum % steel as per Indian standard are: Beam – 4 % of cross-section area. Now, calculating the quantity of steel = total volume of concrete x density of steel x 0. First, you must determine the width and length of the slab. The length of anchorage rebar depends primarily on the type of structure and the size of the rebar being used. It requires careful attention to detail and an understanding of the various. 12 ft). A slab layout plan is a drawing that you’ll get in the structural drawing book. 5 units. 1 m)Rebar Grid Calculator. 2. Our rebar weight calculator is a handy tool that allows you to efficiently calculate the weight of rebar for your projects. 3 of ACI 318. 0 + 6. One Way Slab Bar Bending Schedule Calculation. Number of Required Bars Formula = (Length of slab / spacing) + 1. NOTE: this calculator was updated on 16 Feb 2022 to accommodate the inset of rebar placement from the edge of the slab. Convert Cubic Feet to Cubic Yards and Metres. Calculating The Rebar Spacing For A Concrete Slab. Weight of one m of rebar is 0. NOTE: this calculator was updated on 16 Feb 2022 to accommodate the inset of rebar placement from the edge of the slab. Table 5. As you. Calculating bar spacing requires. The volume is simply the area (A = L*W) times the depth (D). 6m × 5m × 0. 5 feet. 0. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. Conversion. 5)* (bw*s/fyt) Equation 4. or ACI 318M-11 Equation 12-1. For example, let’s find the number of 5′ x 50′ rolls of mesh required to reinforce a slab that is 25′ by 25′. A 30-by-30-foot slab of concrete for a driveway, garage floor, or large patio costs $3,600–$7,200 on average. For a typical 4” thick slab, you should use at least 6” x 6” spacers on each side of the vertical bars, placed at a. For example, if the area is 10 feet long and 6 feet wide, the square footage is 60 feet. The standard allows the application of. 87 (round up to 13) Add one rebar to your outcome: 13 + 1 = 14. Using the Plate Design. Once in position, you can ensure the rebar is firmly in place by hitting it into the concrete with a mallet. And effective cover = nominal cover + 1/2 dia of Tension reinforcement. Concrete - Water to Cement Ratios. . On average, a 60-pound bag of concrete covers about 0. 6 rebar spaced 4 inches on center is P = 8. Choose Round Column (or Round Slab) on the calculator. . Added 54% extra mortar to convert wet volume into dry volume. Calculate rebar length for the slab — RL — using the formula: RL = SL – 0. 2m3 x 7850 kg/m3 x 0. 72 percent. Click the button to calculate the volume of concrete and man-hours (not including mixing) needed for this. Concrete calculators that estimate the amount of concrete and rebar you need for footings, concrete walls, concrete stairs, slabs, patios and driveways. 01942 pounds per linear foot. For a typical 4” thick slab, you should use at least 6” x 6” spacers on each side of the vertical bars, placed at a. If normal reinforced concrete weighs 150 pcf, then a 12” slab will weigh 150 psf. 1. (D) Depth of Slab (e. So you have to divide 320 by 4, which equals 80. Therefore, #2 rebar is ⅛” + ⅛” = ¼” in diameter. Substituting the diameter of 0. The weight of a concrete slab can be estimated by computing the volume of the slab and multiplying the volume (V) by the density of the concrete. Divide your result by the spacing measurement: 180 in / 14 in = 12. 05 percent of steel ireinforced concrete pavement, and the minimun m directions normal to each other for a distance of 3 allowable length of the slabs. Required thickness of concrete slabs. On average are required, for 100 square feet with 5 inches thick slab, 19 strips of 3/8” rods (30 ft each one), are 570 ft. A typical 1,200-square-foot house foundation costs $6,900 to $16,200 for a concrete slab, or about $40,000 for a full unfinished basement. Then determine the space needed between the rebar and slab edge. 2655 = 0. Our calculator will instantly calculate the quantity of rebar required. The Rebar for an Irregular Shaped Slab calculator estimates the total length and weight of reinforcement bars (rebar) needed for an irregular shaped concrete slab. 26897 kg. 260X0. Rebar - Footings and Foundation Wall. The rebar needs to sit within the slab and away from the edge of the slab. of Main bars = (3000)/150 + 1. You will get the results in kilograms (Kg). 37 cubic yards of concrete for a 4×4 slab that is 4 inches thick. For example, if you are using ½ inch rebar, divide 60 feet by 0. The Rebar in a Circular Shaped Slab calculator estimates the total length and weight of reinforcement bars (rebar) needed for a circular shaped concrete slab. Using the above equations, when lb la = 2 l b l a. Concrete volume calculator plan view diagram. You'll see both cubic yards and cubic meters in the answer area. In order to simplify the analysis and to be able to use the superposition principle for evaluating the effect of load combinations, linear analysis is generally adopted even though concrete slabs normally have a pronounced non-linear response. All this procedure is totally automated in SkyCiv Reinforced. 6 feet of rebar. It requires careful attention to detail and an understanding of the various factors that can affect the outcome. The Weight of a Slab with Rebar Calculator computes the weight of rebar in the rectangular slab, and removes the weight of the displaced concrete to provide the best estimate. For example, if SL is 50 feet, RL = 50 feet – 0. The Main bars will be 12 mm in diameter with 100 mm c/c spacing. So, Mass = Density X Volume. Calculate and the answer is 0. Step-2: Get The Slab Reinforcement Details. If your wall is over 20 feet long it will add the amount of overlap required. Closer spacing can also increase the amount of reinforcement and decrease the potential for changes in the concrete’s surface during curing. There are four types of two-way slabs. 9. For example, if you have a slab with a single mat. The deduction from the width will allow a standard 6-inch gap on each side between the ends of the rebar and the edge of the driveway concrete. Assuming that you are referring to the number of steel bars needed for reinforcing a concrete slab, the calculation depends on several factors, such as the steel type, grade, size, spacing, and the dimensions of the slab. INSTRUCTIONS: Choose units and enter the following: Rebar Grid - One Mat (L) Length of Slab (W) Width of Slab (D) Depth of Slab (rS) Size of Rebar (none, 2-11,14,18) (i) Rebar Inset from the edge of the slab. The research is focused on punching shear failure of reinforced ground supported slab. Add 1,000 psi for every layer of rebar installed. Then add 10 percent to allow for spillage and slab depth variations to help determine the concrete cost per yard. For example, the percentage of reinforcement of a 30-inch slab with two layers of No. Post-Installed Reinforcing Bar Guide ). 2. 4 Shear strength of two-way slabs Loads applied to a relatively small area of slabs create shear stress perpendicular to the edge(s) of the area of load application. Placement and bar diameter are important to the structural strength of the concrete. of Wall = the # of concrete blockThe appropriate rebar size depends on the project, with #3 and #4 being common choices. the Android app here: the iPhone app here: The maximum bending moment per meter width of slab, Where, w = total load intensity per square meter of the slab. The formula for the weight of a slab used in this calculator is: Wt = L•W•D•mD. The minimum concrete cover for rebar typically ranges from 25 mm (1 inch). Check it against the factored shear load on the slab, 0. Enter Height 4 ft (or 48 in) Enter Diameter 10 in. Initially, they mostly used in masonry structures to enhance their capacity. Step 4: Place all of the step-up rebar you’ll need at the step-ups in order. 5 % of concrete volume. To. OR, you can add reinforcing steel. 4. Hello everyoneThis is just an overview on how to use the excel calculator to compute for the number of pieces of steel bars (rebar) needed for your slabs vs. 4m3 . of bars = { (L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8 where L or W: length or width of footing. 6m × 5m × 0. To find the Bar Bending Schedule for Slab we use the following formula, No. reduced slab thickness. Equate the balanced moment of resistance to the maximum bending moment; Find the effective depth ‘d’ from the above equation. For the day to day calculations of engineers, fischer offers an efficient way to design post. To calculate concrete for slabs, add ¼ of an inch to the slab thickness, assuming that the job is evenly graded to the proper depth. In other words, post-tensioning pre-compresses the concrete to help prevent cracking from occurring rather thanA minimum area of shear reinforcement should be provided in all regions of a beam where applied shear is greater than half the designed shear strength of concrete. " Multiply the measurements from Step 1 and Step 2 together. 1 For longerHow do you calculate percentage of steel in concrete? Calculate the percentage of reinforcement with the formula P = 8.