1: Calculate The Main bars. E. 113. If the slab is more than 24 inches thick, #5 (#5/8 inch diameter) rebar may be required. Ridges in the surface of the rebar allow the concrete to adhere to it and create one solid structure. Development length = 40d. A good GPR survey and interpretation should give you the rebar spacing and pattern. Foundation and floor slabs for buildings located on expansive soils shall be designed in accordance with Section 1808. 6 Pedestrian Circulation--Stairs and. For example, if you must splice between floors 2 and 3 of a building and you do so just above floor 2, then the construction will look like this: Pouring of column from floor 1 to 2 without the splicing rebar (but with protruding rebar awaiting the splice). 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. Select the unit of dimension like meter, feet inch, etc. Rebar in a concrete slab is crucial to any building. (I think someone touched on this) Your floor covers some span. 53 Compute moments At support: ( - ) M1 = 3. 00 m 14 over 6. 1R and 421. 8 mm) when subjected to 50 pounds (23 kg) applied over 1 inch square (645 mm) of material and are greater than 1/ 8 inch (3 mm) in thickness in the uncompressed state shall not extend beneath walls, partitions or columns, which are fastened to the floor. 74 equals 1824 lbs per sq feet. 1(a)(5) of ACI 318-19 states that the size limitations on aggregates are provided to facilitate placement of concrete around the reinforcement without. 2nd. This slab will have rolling fork lift loads. 1. Matthew Stuart, P. The architect's instructions on the plan are: “New conc slab with #3 transverse bars at 12” O. The height of the slab bolster is determined by the required concrete protective cover. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. We would like to show you a description here but the site won’t allow us. The minimum column size should not be less than 9 "x9". 00 m 7 cantilever reinforced concrete beams 18 mm for every 3. The result is a lightly reinforced slab designed to offset the effects of temperature and shrinkage of the concrete. 3 bars may be used, for constructability and handling reasons it is common practice to use no. com Ezekiel Enterprises, LLC 301 Mission Dr. Type and spacing of the control and construction joints. Specify the spacings: rebar-rebar spacing = 40 cm, edge-grid spacing = 8 cm. In this article, we will examine the importance of reinforcing concrete with rebar and the proper steps. /18 in. I was thinking of going with the same spacing. For areas where heavy vehicles or equipment may be placed, our independent third-party engineers will specify rebar reinforcement for concrete slabs on grade. our detail shows rebar from the top of footing to the second floor (extended above slab for as required for lap) and from 2nd to 3rd floor slab. Figure 1 shows an example of a floor plan with a composite slab including supple - mental reinforcing bars. 5 meters and the support beams are basically 18 x 18 inch reinforced concrete beams that are really strong. Pouring of floor 2's slabThe dead loads include the self-weight of the slab, floor finishes, walls, grills, etc. 2. get your rebar grid down, i would use 1/2" on 12" center. I maintain a concrete cover of 40 MM. 15. The thickness of concrete floor slabs supported directly on the ground shall not be less than 3 1 / 2 inches (89 mm). Grade 40 means that the yield strength is 40,000 psi and the code allowed strength is 20,000 psi. Minimum reinforcement is 0. 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. General Approach to the Design of Post-Tensioned. Generally speaking, a 4-inch slab should include some form of reinforcement such as rebar or wire mesh. The conditions are commonly related to reinforcement ratio, size of rebars, spacing of steel bars, size and spacing of lateral ties or spirals, thickness of concrete […]3. #4 rebar is commonly specified to reinforce the thickened edge. The rating your floor can withstand is also factored in. Narrow panels Fig. The term "composite steel deck floor slab" is applied to systems in which the steel deck has some mechanical means of providing positive interlocking between the deck and the concrete. Rebar is typically made of different types of steel. For slabs of septic tanks, you usually use #3 and #4 bars. Reduce evaporation over the slab by using a fog spray or slab cover. Minimum width and length of slab: See new slab table & figures below. Theoretically, so long as the horizontal spacing is sufficient, the number of layers shouldn't be much of a problem, but the more layers you have, the greater the odds that the vibrator will accidentally touch the rebar (which it shouldn't). g. 4. Modeling floor diaphragms. SLAB—Flat section of floor or roof either on the ground or supported by beams or walls. ICF Foundation and One ICF Story – The sequencing here is to build the foundation walls first, place concrete, and then build the above-grade walls second. For the trapezoidal, dovetail, and reentrant composite slabs, and RC slab, welded rebar meshes with Φ 8 ribbed bars were selected, and bar spacing was 200 mm in both directions. 42d. 5 The second-floor layout of an office facility is shown in Figure P2. The spacing of the main steel in a slab should not exceed the following:First, the American Concrete Institute (ACI) Residential Code Requirements for Structural Concrete (ACI 332-14) requires contraction joints and provides a table to determine joint spacing for plain and reinforced concrete containing up to 0. e. 00 m to 6. ACI 318-08. of main bars – One = [Lx ÷ bar. You can use the concrete Rebar calculations to find the amount of. rebar spacing o. 8. The depth of slab needs to be increased if slab panel size (b) increases, but rebar requirement remains the same for slab (refer to point 3). 8 ). 2-25. We’ll run through these ties now: Saddle ties:As per clause 11. If the pressure on the concrete is to come from the top of the slab, the reinforcement should be laid deep near the bottom of the slab. The imposed loads considered for various types of buildings can be. Concrete slabs-on-ground shall contain micro- or macro-synthetic fiber reinforcement. For footings that are poured before the slab, two #4 horizontal pieces of rebar are required – one 3” from the top and the other 3” from the bottom. So, pathway slabs go under heavy loads continuously. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. 84 m; grid. To define design strip rules, click the Slab Design Rules button on the Data Entry toolbar. The spacing of such shrinkage-temperature steel cannot exceed 18 in. For this case, the lift should not be. Generally, #4 rebar (1/2 inch in diameter) is the most common size used for slab on grade applications. 4th. If 1 span is 8,000mm, 4,000mm will be center part and add 40times (40d) + rebar thickness is the length of top rebar in center part & end. reqd identifying no. of the bars. Section 13. secondary containment floor slabs on grade. 4 bar at the top and the bottom of the footing or one No. Marine Plywood Requirement Area of each marine plywood = 2. 5 kPa), column spacing typicallyRepeat this process until you’ve laid all the necessary rebar. The second marker expresses the bar size and is demonstrated by a number. Pour 6" fiber reinforced concrete over it. This table is span based since the bottom reinforcement is designed span by span. S. Sixteen gauge wire is used to tie. Concrete slabs-on-ground containing 6 × 6 W1. 3. If two or more courts are constru c t e d , expansion joints should be prov i d e d midway between court s. 2-inch slab and 3-inch chairs for a 5-inch slab. 1. 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. Contraction joints (or control joints), when cracked, are really just straight shrinkage cracks. Steel shall be located within 2” of the top or the upper 1/3 of the slab. 4 bars in the middle third of the footing depth. I have reinforced composite slabs 3 ways: all mesh (my least favorite), all #3 bars, or mesh w/ rebar over the beams only for slab negative reinforcement. 3. One Way Slab Bar Bending Schedule Calculation. This new slab design does not account for second floor installations or installations in a ground floor with a basement beneath. mk . . With some limitations, reinforcement for slabs can be sized using the Subgrade Drag Theory in order to increase the spacing of control or construction joints. Typically, once the concrete in the foundation wall has set, install the floor system. 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, #3 (3/8 inch diameter) to #5 (5/8 inch diameter) rebar is typically used. vided in the slab under the net. a car weight about 5000lb. 2—Slabs-on-ground 5. These new concrete slabs do not account for second floor installations or installations in a ground floor with a basement beneath. In the Philippines, buildings face various environmental challenges such as strong typhoons, earthquakes, and floods. Concrete rebar calculator plan view diagram. 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. Minimum aging of new concrete slab: 28 days (cure time) Minimum width and length of slab: See new slab table & figures below MIN W L R S1 & S2 D I LIFT MODELS SLAB MIN. Common Rebar Sizes. To se-lect the appropriate steel area (As), use theFor example, if both slabs have rebar mats that are spaced at 18 inches and use No. Subject: Re: Rebar in shop floor? Kingston,Mi. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. You will be able to add radiant floor heat any time. Rebar is recommended on concrete measuring 5 – 6 inches thick. 2. 3. The numbers range from #3 (smallest) to #18 (largest). We had twisted square bars in our 1911 second floor slab. For example, a slab that is 6 inches thick might have rebar marked as size 6 or 3/4-inch. For corrosion protection, however, most specifications require a minimum depth of concrete cover that usually ranges from 1 inch to 2 inches. 3 Welded wire reinforcement (with wire size not greater than MW30 or MD30) used in slabs not exceeding 3 m in span shall be permitted to be curved from a point near the top of slab over the. Often, concrete contractors don’t have solid runs of rebar anyway. Use 3/8 min repair frame in the footing. 00 m 21 reinforced concrete slab 3 mm for every 3. Assessing General Pier Spacing Requirements In addition to the type of soil or backfill, structural loads , and weather conditions, pier spacing specifications will depend on a few other factors, such as the square footage of the home, floor plan, location of any openings, types of piers used, whether the home has one or two stories, and. However, for post-tensioned (PT) slabs, this can be mistakenly regarded as difficult, expensive, and. For this case, the lift should not be installed without written authorization from theSlab Reinforcement Two-way slabs are generally defined as suspended slabs whose ratio of long span to short span (bay length to width ratio) is less than two. What Size Rebar for Concrete Slab? This usually depends on the intended workload. 8 ). Methods used for finding slab thickness varies for different types of slabs. • Basement floor slabs with integral footings must provide for 5000 psi concrete in that portion of the slab acting as a footing. Tie the rebar together. Methods used for finding slab thickness varies for different types of slabs. 9mm deformed rebar for walls instead of 10mm. E. The roof of a concrete home can be used as a slab-on-grade floor for the wood frame on the second story. I have some question regarding the placement of the expansion joints. Care should be taken to locate any reinforcement bars away from any anchor positions of the specific lift. Since this is a patio, you could use 6x6 10/10 wire mesh instead of the rebar. These provisions are not meant to prohibit the use. x 20. 7. Figure 1. 15 mm) polyethylene vapor retarder with joints lapped not less than 6 inches (152 mm) shall be placed between the base course or subgrade and the concrete floor slab, or other approved equivalent methods or materials shall be used to retard vapor transmission through the floor slab. Shrinkage cracks are probably the most common type of cracks in concrete. I have 10 in. There's no generally-accepted rule of thumb as to how to space rebar in a concrete slab. #3 is most commonly used for patios and driveways, #4 for columns and walls, and #5 for foundations and footers. ( D) Depth of slab. However, this is the absolute minimum and applies only when there is no load on the concrete slab at all. If Steel grade 60 is to be used, the minimum slab thickness is taken as L/20 where L is the span of slab. 27. Fo r decades ACI 318 has re q u i r ed high-Concrete slab-on-ground floors shall be designed and constructed in accordance with the provisions of ACI 332 and this section. 6: 20mm clear cover in slab is sufficient. In either case, blocks should be used under the reinforcement to keep centered. 8. Slab re i n - f o r cement and joint details for this type of court are shown in Fi g u r e 3; a cross section and other typical tennis court details are shown in Fi g u re 4. • A beam-and-slab system, with a one-way slab, and beams cast compositely with the slab, is a highly efficient floor system. ACI 332, Section 10. The steel rods help reinforce the strength of the concrete slabs giving the structure a strong form. They are used to support the concrete, which would move and break if set against soil alone. Sand is filled at a height of 0. Fa b r ic may also be supported at the center of the slab, or it may be installed in two flat layers with the top layer (nega-t i v e steel) extending on either side of the support for one-quarter of the span (See Fi g u r e 1). Thus, the maximum center-to-center spacing, s, of the deformed longitudinal bars to limit crack widths is given by the following equation (see ACI Table 24. Rebar is recommended on concrete measuring 5 – 6 inches thick. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. make sure rebar is in the center of the slab, or close to it. LIFT MODELS. There are many variables that influence the decision of how much space to leave, including the maximum load the slab is likely to. 5 inches up to 12 inches. Floor Under Solids or Semi- solids and Single Axle load (15,000 lbs. 5-TM 5-809-1/AFM 88-3, Chap. In the farwestern states, the rebar supplier also ordinarily places the bars, In the New York City area,…. Jade Paul D. 1: Calculate The Main bars. SLAB ON GROUND—A type of foundation with a concrete floor which is placed directly on the soil. Rebar being #4 grade 60. of the most advantageous location for a floor opening depends on the type of two-way slab you’re designing or evaluating. The maximum size of reinforcement shall be No. When two slabs are moved together, the impact loading created by the slab is reduced. Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the slab. Figure 1b: Joint Spacing in Feet Contraction joints may be tooled into the concrete surface at the time of placement. 3. Also, a small hole in the concrete will be totally fine, given the fact that there is a rebar grid. Input the number of mesh in slab rebar. Maximum spacing: The maximum spacing of main bars is limited to 3d or 300 mm (whichever is less). The minimum spacing between two reinforcement bars should be at least equal to the maximum coarse aggregate dimension plus a margin of 5 mm. . 20mm clear cover is sufficient for intermediate floor slabs, and 30mm clear cover should be provided for roof slab exposed to rain (c). 2. This steel runs vertically and should lap the same size reinforcing steel out of the footing. If you are trying to put a new concrete slab on your small-scale domestic project; 6mm (#19), 8mm (#25), and 10mm (#32) rebars will do the job nicely. • The slab is designed as a continuous slab, using theory of continuous beams (slabs), or the simplified ‘coefficient’ method (where applicable i. Cracking can be the result of one or a combination of factors, such as drying shrinkage, thermal contraction, restraintRebar Development Length Calculator. g. For driveways and patios, #4 (1/2 inch diameter) rebar is a common. Wire mesh. 23 Total factored load = 6. a) Slab depth does not exceed 250mm when the steel grade is 250. Glass fiber reinforced polymer. 9 ”x9” columns are to be used for a single-story concrete grade M15 (1: 2: 4) structure (cement: sand: aggregate). 2: Repeat and continue to draw complete (closed) shape. We would like to show you a description here but the site won’t allow us. To calculate Total Area of a multi sided slab, first divide the shape into rectangles or squares. . Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. 6) Calculation of top rebar Please refer to the method in construction site as follows because it is very difficult to explain in theory. Determine the rebar gauge. The movements of these structural elements are likely different than those of a slab-on-grade due toWhen operated by our highly trained Project Managers, GPR’s typical accuracy is +/- ¼” to the center of the object in concrete we locate: conduit, post tension cables, and rebar. Basement slabs and interior slabs on grade, except garage floor slabs: 2,500: 2,500: 2,500 c: Basement walls, foundation walls, exterior walls and other vertical concrete work exposed to the weather: 2,500: 3,000 d:. That is the best way to have good concrete in such a place. Calculate how much rebar you need to reinforce a concrete slab. But if the slab is a patio or driveway, it will need rebar. These beams are not fixed together with a slab as are superstructure beams; consequently concrete has to be poured down the beam’s narrow top opening and reach the bottom of the beam. We would like to show you a description here but the site won’t allow us. 1. Joints shall be spaced at 24 to 30 times the slab thickness but this need to be confirmed by a structural engineer. If consolidation of plastic soils is determined to be a potential problem a suspended slab may be the only effective solution, in which. Clear span of the two way slab = 5000 mm. . I generally use a minimum of 4 bars, with 2 bars of 12 MM thickness in the bottom of the beam, and 2 bars of 10 MM at the top of the beam. Second level 6 inches thick 9 feet tall. Finally, take a look at the calculation results: grid length = 5. I'm in the process of designing a elevated composite concrete and metal deck floor slab for a warehouse. A 6-mil (0. e. 9 Factored loads Factored dead load = 3. This configuration directs load transfer predominantly in a single direction toward the columns. Locating conduits (plastic & metallic) and in-floor heating lines in concrete, or just below a slab-on-grade. 15. 600-2 DETERMINATION OF BUILDING WIDTH A. 2R for suspended floors. (as in example diagram) First, enter the concrete slab sizes: length = 6 m, width = 4 m. First step of the fixing of slab reinforcement was placed the bottom most R/F (B1) of the slab. Table 7-6. area elements and go to Assign > Shell/Area > Opening to create holes in the slab. Most homeowners can expect to pay between $4. Tying is required at every second or third intersection, depending upon the size and spacing of bars, but with not less than three ties to any one bar, and, in any case, not more. In the case of the RCC slab, the maximum spacing between two secondary parallel wires should be 5D or 450 mm or whatever. 7. FIrst, find number of rods required for main reinforcement and distribution. For example, at Column I-4 between the basement and first floor, building plans required four pieces of horizontal rebar through the column in both directions to connect it to the slab. Functions of Distribution Bars In A SLAB: Distribution bar is to provide at the long span of the slab. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. 2. 2. , and unfactored live load = 100 psf. It may be desirable to tie and reinforce the new slab to the pre‐existing surrounding floor. 1 Flexural Cracking in Reinforced-Concrete SlabsFor mid-depth rebar, the program will use the bottom bar size and spacing options. Penetrations in PT slabs are possible when observing proper methods. Grads Slab/ Slab on grade: The slab which is cast on the surface of the earth is called a Ground slab. Use VERIA's free construction material quantity calculator to aide you in estimating for the materials and labor man-hours of all your construction projects. The typical depth for rebar placement for slabs is 2-4 inches. 1. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. After pouring concrete walls, they are anywhere from 8 to 10 inches thick. #construction #Philippines #staircase #stair #stairs #stairsPhilippines#steelbar #rebar #stairrebarRebar details for stairs and slab ThicknessAmerican Concrete Institute—there's not much available free from ACI, but if you want the best information on concrete and concrete parking lots, ACI has it. Also note while no. spacing requirements and to repeat bar size and spacing as often as possible. 6 of the International Building Code. 00 m 21 reinforced concrete slab 3 mm for every 3. 1d is for every 45° bend. For distribution bars the maximum spacing is specified as 5 times the effective depth or 450 mm whichever is less. In inches the diameter of a #5 rebar is 5/8″ and that of a #4 rebar is 1/2″. In this video, you will learn the Spacing between the Main and Distribution steel bar. The spacing of the rebar is also determined by the weight and size of the slab. I'd use: 8" thick concrete wall with #6 rebar at 12" oc EACH WAY with the VERTICAL rebar placed 3/4" clear from the face of the INTERIOR BASEMENT ROOM. Why? While concrete is very strong in some ways, it also has a few. 4. That is, there are breaks in the rebar along the runs. Where, d is the diameter of the bar. 46 and $1. When concrete is first mixed and poured, it has excess water in it and in the hardening process, the concrete loses its excess water which causes shrinkage cracks. Map rebar and rebar patterns. With this calculator, you’re trying to calculate the dimensions of your rebar grid (length and width). 00 m 14 over 6. 59 per square foot. In some cases, concrete needs reinforcement with steel mesh. First, Get The Number Of Required Bars. Corner angle. 53 m). Step-4: Rebar Calculation Process Of The Slab Panel-A 4. Fiber length shall be 1 / 2 inch to 2. 42), the overhanging flanges of. Floor slab of bottom-most SS or NS and floor slab of NS located above an SS: (i) Slab reinforcements at both external face and internal face shall be H13-. There are many variables that influence the decision of how much space to leave, including the maximum load the slab is likely to have to support, the bearing capacity of the soil, the diameter of the reinforcing rebar, the likelihood of frost heaving the. 6. , interior beam dimensions = 14 in. An example is shown in Fig. Labor Costs. 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. 5. If shear reinforcement is required for in-plane strength, spacing of longitudinal reinforcement shall not exceed l w /5. 3rd. Sudip Shrestha. 40 (default) and 60 are common. Basement slabs and interior slabs on grade, except garage floor slabs 2,500 2,500 2,500a Basement wallsc, foundation walls, exterior walls and other vertical concrete surfaces exposed to the weather 2,500 3,000b 3,000b Driveways, curbs, walks, patios, porches, carport slabs, steps and other flatwork exposed to the weather, and garage floor slabsThe Rebar Calculator is now available in Spanish. And a cross-sectional area of 0. : Theoretically there is no difference because the restraint to movement is the same in all cases. 5, which correspond to diameters of 3/8-inch, 1/2-inch, and 5/8-inch, respectively. This is illustrated in Figure 1, where #5 bars are used in both the top (T) and bottom (B) layers in T wo-way slabs are generally defined as suspended slabs where the ratio of the long to the short side of a slab panel is 2 or less. 3. 4 rebar in the lower part of the foundation. Consider. The slab is constructed on well compacted granular fill, crushed stone or marl. Annex. Typically, once the concrete in the foundation wall has set, install the floor system. It says that floor slabs were patent designs back in the 1920's. For example, The #3 bar size is 3/8″ diameter of the solid section, the #4 bar size is 4/8″ diameter of the solid section, and the #5 bar size is 5/8″ diameter of the solid section. NOTE: Section 1907. Important Points. Learn the steps to pour a concrete floor inside an existing garage, house or shed. The simplest type of two-way slab to construct is known as a flat plate. The national average cost of a concrete slab is $6. However, the boilers I have been recommended is the Electro boiler (30,000. Learn More. The second table describes the negative (mid-span) moment demand and the bottom reinforcement. 2 consists of a 3-inch-thick reinforced concrete slab supported by steel beams. I was thinking of going with the same spacing. 3. t + d Lsy. Generally, rebar has an immense impact on concrete. The openings are square in shape and range in size from 2 ft to 5 ft. 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. 00 m to 6. Purpose. 2: Repeat and continue to draw complete (closed) shape. Exposed rebar will rust, compromising the concrete's strength. Once you have determined that the foundation of the house is strong enough to sustain a concrete floor, lay down wood sheeting. Make sure it is in the very center of the slab as if it is too close to the top or bottom it is also useless. 125mm. The number ranges from 10-to. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. 5 kPa), column spacing typically ranges from 15 to 25 ft (4. Contact*: Severity*: Description*:Problem #3 – Shrinkage cracks that allow moisture to reach the rebar. The main reinforcement of the slab panel “A” is marked as (1). 00 m span 3. Contractors sometimes use the “1/8 Rule,” meaning the size of the rebar is 1/8 the thickness of the slab. ”In particular, for slabs containing less than minimum quantities of conventional tensile reinforcement (i. However, in some cases, 10mm dia bars are taken for the floor slab, when there is no extra external load other than reinforcement mesh load. A 4" slab should have joints 8-12 feet apart. If the maximum diameter for slab thickness is 75 mm, so the diameter of reinforcing bars should be 8 mm. In that case, a layer of rebar near the bottom or at. the calculator will give you the default spacing values (for rebar – rebar it’s 40cm, and for edge – grid it’s 8cm). , 12, 24,. A. 1. Much of your need for reinforcement will be dictated by how well your site was prepared. 30% carbon cont ent and only. ACI 302. For a 12 inch (30. 74 sq feet 5000/2. Slab may be supported on walls or beams or columns. 8 of the Florida Building Code,. C. 5% reinforcement (reproduced here as Table 1). 1 the spacing of links along the FULL HEIGHT shall not exceed 6 times diameter of smallest longitudinal bar or 150mm. 34 inch (8. Once you input these values, you. 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. Reinforcing steel should be properly tied with wire to rigidly support it in its proper. 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. Two layers of steel bar reinforcement are needed for secondary containment floors because tank loads induce both positive and negative bending moments in the floor.