"Guide for Concrete Floor and Slab Construction" ACI 360R-06. The current design codes discuss the effective compressive strengths of columns, which reflect a decrease in load transfer performance that can occur when columns and slabs have different concrete compressive strengths. Input length, width and depth of the area. The Total Grid Rebar Length calculator computes the total length of rebar needed for one or more mats of rebar in a concrete slab. ACI 318-14 Section 25. 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. Then add 10 percent to allow for spillage and slab depth variations to help determine the concrete cost per yard. OR, you can add reinforcing steel. You’ll consequently require 14 lengths of rebar. 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. 2. Concrete rebar calculator plan view diagram. Using the calculator, you would find that you need approximately 73339 pieces of rebar for the slab. The following factors have the biggest impact on cost. Labour Requirement for 1m 3 of RCC:Maximum area of longitudinal reinforcement The maximum area of tension and compression reinforcement in reinforced concrete beams is;. 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. Re-Bar Calculator for a Slab using Custom Cut Lengths. NOTE: this calculator was updated on 16 Feb 2022 to accommodate the inset of rebar placement from the edge of the slab. 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. 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. Added 54% extra mortar to convert wet volume into dry volume. The net result is a more accurate and less. The PT Calculator is ideal for owners, developers, contractors, architects, and engineers who need to quickly estimate quantities and concrete sizes. To truly reinforce concrete, the percentage has to. area = 625 sq ft. This study presents structural performance of large scale two-way concrete slabs reinforced with FRP rebars, and their performances were compared against conventional steel reinforced. I’d use #4 rebar at 12” on center each way in a 4” slab. 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. 5% of concrete volume, weight of steel required will be: =196. 2(3) . . This is usually taken to be 75% of the steel yield stress. (inches) Enter the required splice (overlap) of your bars. coverage = 5′ × 50′. Layout of Rebar for Concrete Slabs to Estimate the Quantity of Rebar in Slab. Steps to calculate weight of concrete slab in following:-. 4m mesh is required. The steel working stress must be great enough to. I'm casting a 4m long triangular-profile reinforced gravity retaining wall against soil movement due to a 1 metre jump in ground level. of Main bars = (3000)/150 + 1. 2 kg. Products. Now, calculating the quantity of steel = total volume of concrete x density of steel x 0. 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. of Main bars = (3000)/150 + 1. ( RL) Length of the pre-cut rebar sticks being used to. INSTRUCTIONS: Choose units and enter the following: (r) Radius of Circular Slab (e. These slabs are supported directly by the columns and have a completely flat soffit. Concrete slabs thinner than 4” typically don’t need rebar. area = 25′ × 25′. Self-consolidating concrete (SCC) often requires larger-sized rebar to enhance its strength, such as #11 or larger. For example, if the area is 10 feet long and 6 feet wide, the square footage is 60 feet. Now, calculating the quantity of steel = total volume of concrete x density of steel x 0. A: A rebar spacer is a piece of concrete block (usually 25 to 50mm cube or 50mm dia cylindrical) intended to provide spacing between the outer surface of the finished concrete and the reinforcement inside. The length of anchorage rebar depends primarily on the type of structure and the size of the rebar being used. This spreadsheet is very useful for making design of reinforced concrete sections. Hollow-core concrete slab**: 10 kg tendon. In the two-way slab, the same practice as mentioned above should be followed for both directions. Phone: 800-347-7141 | Fax: 510-490-7179. NOTE: This Calculator should be used as an estimating tool ONLY. 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. 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. 5 % of concrete volume. The maximum bending moment per meter width of slab, Where, w = total load intensity per square meter of the slab. 84 m; grid. SOLUTION. 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. R9. The PT Calculator can be used for the following building types: Podium slab with 3 levels of wood construction (4 levels of wood with roof) Podium slab with 4 levels of wood construction (5 levels. Rebar Calculation For Slab Step-1: Get The Slab Layout Plan. As per thumb Rule, the amount of steel quantity required for an RCC roof slab should be 1% of total volume of concrete slab. 395 kg/m. With this calculator, you’re trying to calculate the dimensions of your rebar grid (length and width). 075)kN m2 × 1m = 9. For example, if the percentage is 0. 0009fy - 24)d; [ For fy > 60,000 psi] The minimum lap length for compression bars must be 12inches. The experimental program was designed to evaluate how flexural performance at service and ultimate limit states are affected by a one-to-one replacement of Grade 60 with CRR bars, a reduction of concrete clear cover, and a reduction in rebarThe use of the rebar bar in construction extends up to the 15 century for masonry structures. Placement and bar diameter are important to the structural strength of the concrete. Chapter 11—Fiber-reinforced concrete slabs-on-ground, p. The main standard for fiberFor λ = 1. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. 2, see D. NOTE: this calculator was updated on 16 Feb 2022 to accommodate the inset of rebar placement from the edge of the slab. How do you calculate rebar spacing? Find the rebar-to-spacing multiplier with the formula M = 0. 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. This calculator is to be used as an estimating tool only. 1,IS 456 provided short span is <3. We first obtain the total factored bending moment to be carried out by the slab’s unitary width strip. Mass / Volume Conversion. 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. 4. By special permission of the publishers, Co n c re t eproject has two structures, both of them have removal of concrete, class B concrete, and new strip seal expansion devices. 5(alternate) and 5. d = 150 mm _ 26 mm. A rebar slab calculator is a tool used to determine the quantity and spacing of reinforcing bars (rebars) needed in a concrete slab. 87 (round up to 13) Add one rebar to your outcome: 13 + 1 = 14. Therefore, #2 rebar is ⅛” + ⅛” = ¼” in diameter. Concrete slab resting o n grade containing minimal distributed st eel, usually of weld ed wire fabric (WWF), for the purpose of limiti ng crack width due to shrinkage and tempera-ture change. that is 2. Now the 6% of the above value = (2/100)X12. The volume is simply the area (A = L*W) times the depth (D). (feet + inches) Enter the width. Length of bar = L or W–concrete cover for both. 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. 08 x 50 = 4 total cubic yards of concrete for 50 tubes. Fire design of cast-in place and post-installed anchors in concrete under fire is covered by EN 1992-4, Annex D, allowing steel- and concrete-related failure modes of anchors to be calculated. 0 % of concrete volume. There are also specific provisions addressing concrete slabs and shotcrete. Value of Ce = 20 mm + 12/2 = 26 mm. 6 rebar spaced 4 inches on center is P = 8. 01 = 235 Kgs. The slab. The changing point in the use of the rebar in construction is the 19th century with enhancing its strength by embedding it in the concrete. 33_6_0. 3. Building a concrete slab foundation costs $5 to $14 per square foot or $4,000 to $33,600 total on average. The Rebar Weight calculator computes the total weight(w) of rebar based on the length (l) and size (s) of rebar. To estimate costs for your project: 1. 65*6) = 1. Finds how many rebars you need to create a reinforcement in the slab. There are four types of two-way slabs. Step 4: Place all of the step-up rebar you’ll need at the step-ups in order. 125 - 0. 3 inches)(oC) on-center. It is generally accepted that rebar should have minimum 6″ clear cover from all edges, corners, and other forms of reinforcement. 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. That way you can use the forms themselves as a guide for the final base height. If an end-to-end distance between the lap is the least, then the lap should be provided in a staggered manner. Calculation of concrete cover for bond The minimum cover for bond c min,b is calculated in accordance with EN1992-1-1 §4. 5. 6 feet of rebar. Video Shortcuts:@0:45 Prep w. 2) Development of the bar does NOT ensure that a concrete breakout failure will not occur. 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. 4 wire mesh in a 4-inch slab, P = 8. For heavy-duty purposes. Substantial reduction in joints, i. 1100 at 12” on center, therefore, . How much rebar do you need? How to calculate the quantity and size of steel reinforcement in a concrete suspended slab the easy way! Work out loads, then ben. Noncontact lapping length generally shorter than contact lapping length. If your wall is over 40 feet long it will add 2x the amount of overlap required. One Way Slab Bar Bending Schedule Calculation. Choose Round Column (or Round Slab) on the calculator. Eliminate the need for thickened slabs at joints and e d g e s . 08 cubic yards for one concrete tube. 1 A Nco = projected concrete failure area of a single anchor, for calculation of strength in tension if not limited by edge distance or spacing, in. 5. 19 0. For example, if SL is 50 feet, RL = 50 feet – 0. ACI code 7. 12. Ft. Total rebar weight 53. 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. It’s a time-saving solution that eliminates the need. Estimation of steel reinforcement quantity is a necessary step in calculating cost of RCC structure along with other building materials as per. (inches). Similarly for other structural components, the quantity of steel can be worked out. It requires careful attention to detail and an understanding of the various factors that can affect the outcome. Step 3: Determine the thickness: Measure. "Specification for Tolerances for Concrete Construction and Materials" ACI 302. Provide the required spacing and diameter of the rebar. Our chairs provide a 3″ ground clearance and 5. 2. The appropriate rebar size depends on the project, with #3 and #4 being common choices. Slab footing Rebar may be easily determined with the help of the footing Rebar calculator. The rebar is built in a grid structure and costs $2 to $3 per square foot. If a slab contains stirrups, their spacing must not exceed 4 inches. Sounds easy, but the trick is to de-t e r mine the amount of beam cam-This calculator uses 35% of balanced rebar area as the steel area for design of slab. 2. Required thickness of concrete slabs. of Main bars = (Width of Slab/Spacing) + 1. How much concrete do you need for a slab? Calculate the amount of concrete you will need. Concrete slabs: Contractors often use the 1/8 rule for determining the size of steel for a slab. Concrete is sold in cubic yards (27 square feet), so you will need to multiply your square footage from Step 1 by the depth of. or ACI 318M-11 Equation 12-1. Step 3: Determine the thickness: Measure. Control the domains or regions to design under different reinforcement settings, to help minimize materials and design more. 00 per hundred pounds or $80 per ton more than for #4 bars. (b) A flat slab which is the same as a flat plate except the areas around the columns have increased thicknesses, called. (default is one). 65 and the thickness of the slab is 6 inches, M = 0. 35* (bw*s/fyt) Equation 5. Description. Foundation Cost. Multiply the length (10 ft. Footings are especially important in areas with troublesome soils. Columns that support flat plate slabs and columns that are supported by footings are the most common examples. 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. Reinforcement for shrinkage and temperature stresses normal to the principal reinforcement should be provided in a structural slab which the principal reinforcement extends in one direction only. Using the above equations, when lb la = 2 l b l a. . Choose the unit of all the dimension like, length, width, and thickness of slab in different unit like mm, cm, inch, meter, foot etc. 4. The process of calculating rebar spacing for a concrete slab is like solving a puzzle. This will mean that the horizontal rebar may be higher to account for the hoop stresses coming out of the page but this is much more efficient than using the. Multiply the measurements together to calculate the square footage of the area. Structural concrete. A base of gravel will help prevent erosion and keep the slab from settling. The minimum compression development length shall not be less than 200mm. Column: 100 kg of normal rebar steel. Inches. The calculation of concrete cover takes into account the requirements for structural performance, fire resistance, and durability. The Distribution bars will be 8 mm in diameter with 125 mm c/c spacing. Step 2: Calculate the area: Multiply the length by the width to find the area of the slab in square feet. Calculate the volume of cubic yards needed to fill in a square or rectangular slab pour for flooring, walls & similar structures. Set the forms at the proper height before bringing in the last lift. "Deign of Slabs-on-ground" ASCC Position. Inches. 3. pmax=CwCc [150+9000R/T] for walls with a rate of placement of. Feet. Like our other calculators, this reinforced concrete Beam Capacity Calculator is very easy to use. I’d use #4 rebar at 12” on center each way in a 4” slab. Concrete volume calculator plan view diagram. Post-tensioning is an active rather than passive form of reinforcing. For live loads of about 50 psf (2. 4. 85Vc > Vu. 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. For example, the length is 20 inches and the width is 15 inches, the area is. Standard Data used in this Calculator. 66 per square foot*. Step 1. No. For column = 2. 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. The article handles potential approaches to design and determination of total load capacity of foundation slabs and floors. 2. 01. The rebar within the concrete takes in some of the force applied to the concrete matrix. Wall, internal element (for instance 180 mm): 35 kg of normal rebar steel. 87 (round up to 13) Add one rebar to your result: 13 + 1 = 14. Convert your longitude measurement into inches: 15 feet x 12 inches per foot = 180 inches. The current design codes discuss the effective compressive strengths of columns, which reflect a decrease in load transfer performance that can occur when columns and slabs have different concrete compressive strengths. 72 percent. " There is also a Settings button so. 2: Repeat and continue to draw complete (closed) shape. These are known as rebar sticks. The Rebar Volume or Displacement calculator computes the total volume (V) displaced by rebar based on the length (L) and size (S) of rebar. 5 allows for sufficient clearance for fitting the rebar within the slab. Divide your result by the spacing measurement: 180 in / 14 in = 12. Width (feet) width x12. The research is focused on punching shear failure of reinforced ground supported slab. See full list on inchcalculator. yds. The finite element method is commonly used to design the reinforcement in concrete slabs. In this video I show from start to finish how to prep , form and pour a 6" thick concrete slab thats reinforced with 1/2" rebar. R – Radius of the slab. Introduction GeneralThese totals are shown in the TOTALS row. This reinforcing steel is called “temperature steel” and is not used for spanning soft spots, etc. For direct tension, Lap length = 2 x L x d or 30 x d (The greater value among the two values calculated is taken. 88782 kg. 5)* (bw*s/fyt) Equation 4. Every concrete slab should have a minimum. 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. A: A rebar spacer is a piece of concrete block (usually 25 to 50mm cube or 50mm dia cylindrical) intended to provide spacing between the outer surface of the finished concrete and the reinforcement inside. One way slab d= (L/22) to (L/28). ( para español, HAGA CLIC AQUÍ) . e. 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. Slab footing Rebar may be easily determined with the help of the footing Rebar calculator. Here’s what you’ll need to do before you pour any concrete: 1. Find a Spot and Make a Frame. 2) height of chair:- vertical distance of chair bar is known as height of chair, it is main part of calculation to find and how to calculate height of chair bar Height of chair = depth of footing _ (upper and lower clear cover of concrete + bottom. If the steel. 395 kg/m. The rebar securely snaps in and doesn’t move when the concrete hits it. Section 11. 3. · Enter the Thickness of the slab in mm only. =7. The Concrete Weight formula computes the weight of a volume (V) of concrete. Fill in the price and single rebar length that you will buy at your supplier: rebar price = €2/m single rebar length = 6 m. The Clear cover will be 25 mm (Top or Bottom) and the thickness of the slab will be 150 mm. Steel weight required for above slab = 3 x 7850 x 0. 1—Introduction 11. A s,max = 0. If you can get 20' long bars the total length of your slab can be 20'. This is a non-destructive probing method. Where; A c is the area of the cross-section Shear Reinforcements (links and stirrups) The minimum area of shear reinforcement in beams should be calculated from; A sw. In such a case, the straight lapping length of the reinforcement bars must be greater than 200mm or 15 x d. FIrst, find number of rods required for main reinforcement and distribution. This reinforcing steel is called “temperature steel” and is not used for spanning soft spots, etc. Rebar is typically calculated at a rate of 1 for every 8 inches of footing width. 01 x 7850 x 2. ls = (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. Values of α 1, α 2, α 3 and α 5 may be taken as for the calculation of anchorage length but for the calculation of α 3, ΣA st,min should be taken as 1. For heavy-duty purposes. 4. 1 ABefore calculating the steel rebar reinforcement, it is recommended to check the shear capacity of the slab, one for direct shear in the connection and the other for the punching shear capacity on the connection slab column. For each additional 20 foot increase of the wall. Maximum % steel as per Indian standard are: Beam – 4 % of cross-section area. 2: Repeat and continue to draw complete (closed) shape. Feet. Once this is complete, you will need to add the steel reinforcement bars (or similar) by clicking the "Add/Edit Steel Reinforcement. Determine the rebar gauge. The Weight of a Slab with Rebar calculator estimates the weight of a rectangular slab including rebar (if used). 2. 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. Slab concrete properties definition before design optimization. Relative strength of wire mesh vs rebar for reinforcing a concrete slab. 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. The national average cost of a concrete slab for a garage is $6. ;. ( para español, HAGA CLIC AQUÍ) . 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. Length (feet) length x12. epoxy-coated reinforcing steel was compared to deck slab specimens where Grade 60 is replaced with CRR bars. The effective compressive strength of a column increases as it is confined by the slab, and the. Slab volume is calculated by multiplying the length, breadth and depth of the slab as 6m x 4m x 0. 2m3 x 7850 kg/m3 x 0. 9_sqrt (0. 74 sq feet 5000/2. Calculate volume of concrete i. Slab using custom cut. Report Application Issues or Provide Customer Feedback. Rebar. However, no matter how basic or complex the floor is, the construction method is similar and includes; preparing the sub-grade and sub-base, placing the reinforcement and. Noncontact lapping length generally shorter than contact lapping length. Click the button to calculate the volume of concrete and man-hours (not including mixing) needed for this job. Step 1: – Calculate numbers of distribution rods. For multi sided slab, first draw the shape: 1: Hit Clear + Start and enter Side Length of first side to draw, then hit appropriate direction (Arrow) button to draw. = 565. In the following tutorial, we will explore how to model, analyse and design a concrete slab on grade using the SkyCiv software. 40X13. Total rebar length 60 m. (as in example diagram) Multiply the 2 different side lengths of each rectangle to find individual areas, then add them together to find Total Slab Area . All reinforced concrete references for slab design divide into one-way and two-way if the quotient of lb la l b l a is greater or less than a value of 2, respectively. Then, find the length of one bar. Calculate how much rebar you need to reinforce a concrete slab. Most concrete slabs are cast monolithically with supporting beams, with portions of the slab participating in flexural resistance of the beams. For flat slabs, grid spacing of 18 inches for driveways and 24 inches for patios is recommended. Figure 14 represents the plate’s local axes. 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. Suspended slab formwork and rebar in place, ready for concrete pour. It requires input values for the. 4m3 . We first obtain the total factored bending moment to be carried out by the slab’s unitary width strip. 0, 8 λ (ρ w) 1/3 becomes equal to the value 2 λ for a longitudinal reinforcement ratio ρ w = 1. As you. Otherwise, you can divide the slab area by 0. 3. If you can get 60' long bars the total length of your slab can be 60'. For compatibility with older ACI codes, Ψr is taken as 1. 6. xls" also included in this repository. In this section, we will calculate the required reinforced steel rebar using the reference of the Australian Standard. 1) Measure all dimensions (Length, width, and thickness) of concrete slab in feet, 2) Multiply length of slab by width and by thickness to determine cubic footage. Generally, the minimum amount of rebar recommended by the American Concrete Institute (ACI) is at least one vertical bar per cubic yard of concrete and two horizontal bars, either laid flat or tied together with wire. 72 percent. For RCC Roads, 0. Rebar Weights: The table below is based on a 10 % lap and works with any diameter rebar. 2. For one layer of 6x6 W1. The percentage of reinforcing refers to the cross-sectional area of the steel for a given width of slab divided by the cross-sectional area of the slab area considered. g. Closer spacing can also increase the amount of reinforcement and decrease the potential for changes in the concrete’s surface during curing. Most residential slabs use #3 which is 3/8” diameter (3/8in² cross-section) or #4 which is 1/2″ diameter (1/2in² cross-section). of bars = { (L or w – concrete cover for both sides) ÷ spacing} +1 Equation 8 where L or W: length or width of footing. Volume of the slab = Length of the slab X Width of the slab X Thickness of the slab. Next, divide the total square footage by the size of the rebar. First, enter the concrete slab sizes: length = 6 m, width = 4 m. Additionally, additional bars should be placed 12” apart along all. The formulas calculate materials needed. 10m= 3m3:- here we have slab of 6 meter length, 5 meters width and 100mm or 4″ thick, so volume of concrete of slab = 6m × 5m × 0. The only formula you need to remember for the entire calculation is . 3. For example, if the length is 10 feet and the width is 8 feet, the area would be 10 x 8 = 80 square feet. In this method, forces transfer from one bar to the other through concrete. Quantity Estimate for Reinforcement in Kg: Quantity Estimation of Reinforcement in Kg. 63ρb [ACI 318 Sec. In this section, we will calculate the required reinforced steel rebar using the reference of the Australian Standard. Now the maximum quantity of steel in slab is 2% of the volume. 9 of ACI 318-14 or Section 12. 5 feet. 1. of Main bars = 20 + 1 = 21 Nos. The net result is a more accurate and less. Strength. Pre-stressed concrete beam: 30 kg of tendon and 30 kg of normal rebar steel. Finally the calculated concrete and steel forces Fc, Fs, Fcs and their position from the section neutral axis a c, a s, a cs allow to calculate the design moment resistance from the following equation: M u = F c ∙ a c + F cs ∙ a cs + F s ∙ a s. for more FREE video tutorials covering Concrete Structural DesignThe objective of this video is to determine the area of bottom reinforc. Calculating bar spacing requires. Radiant heat tubing in a concrete slab needs to be closer to the top of the slab than its bottom, normally in the top 2-inches of concrete. Enter the length. 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. 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. The Main bars will be 12 mm in diameter with 100 mm c/c spacing. 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. Thumb Rules For Shuttering Work. 04A c —- (3).