Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. 2)(12 in. The support for reinforcing steel in floor slabs is shown in figure 7-24. GPR can help with: Pinpointing structural elements in concrete such as. 34 and $7. The minimum size and grade of rebar for slabs depends on a variety of factors, such as the thickness of the slab, the loads it supports, seismic requirements and other factors. Rebar is typically used to provide additional strength and rigidity to concrete slabs, so if the slab is intended. Often, concrete contractors don’t have solid runs of rebar anyway. or slab change soffit typical detail for beam 400 dowel 250 300 (typ. I am pouring a slab for radiant heat next week and I have been given a variety of advice on whether or not to use rebar. Jade Paul D. Reading time: 4 minutes. 5 inches of spacing (18" + 1/2" diameter of the rebar). 60 per square foot. 5 kPa), column spacing typically ranges from 15 to 25 ft (4. 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. extension of existing reinforced concrete (R/C) structural elements such as slabs, walls, and columns (Figure 3), either to facilitate expansion of floor space or to address other functional changes in the use of the structure. 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. Figure 1a: Joint Spacing in Meters. Main bars in the slabs should not be less than 8 mm if you are using the H. For example, one-way slab thickness. Glass fiber reinforced polymer. Number of Distribution Bars = Lx / spacing + 1 = 3000/150 + 1 = 21 nos. 006 inch; 0. . In the process, install bar chairs (various types are available) in cores where vertical rebar must be installed. Reduce evaporation over the slab by using a fog spray or slab cover. 5 kPa), column spacing typicallyRepeat this process until you’ve laid all the necessary rebar. Concrete volume calculator plan view diagram. In t e r p r etations of the ACI 318 code re q u i r ements (Ref. I’m on the second floor and the floor is 6 inch concrete slab with I think at least 1 inch steel rebar as reinforcement. 5 The second-floor layout of an office facility is shown in Figure P2. A typical installation uses 6-inch by 6-inch woven wire mesh, which is supported on rebar chairs so it is positioned near the center of the finished slab. 1) for con-c r ete cover over re i n f o rc e m e n t h a v e not been consistent. Our engineers wanted to make sure that big yellow boots fit between the rods so the workers did not stand on the rod and bend or. E discuss natin dito ang Lapping Zone, Lapping length, Stag. opening is framed by beam bars up to beam support in two way slab extend 400This video demonstrates how to theoretically calculate the sizes and spacing of steel bars of suspended slab and concrete stairs. 00 m 14 over 6. 14 and No. In two-way construction,According to Clauses 8. That has held up great over the last 8 years, no cracks at all. 7 For temperature steel. 3. Sub-slab details (i. The installation of the rebar is critical for the success of the overall project. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. Minimum spacing between reinforcement bars in foundation tie-beams Concrete casting in foundation tie-beams is not an easy procedure. For slabs (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. The maximum spacing of temperature steel is the smaller of 5 times the slab thickness or 18 in. 00 m span 3. Pour 6" fiber reinforced concrete over it. ( D) Depth of slab. 3. These new concrete slabs do not account for second floor installations or installations in a ground floor with a basement beneath. There are many variables that influence the decision of how much space to leave, including the maximum load the slab is likely to. The simplest type of two-way slab to construct is known as a flat plate. 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. 00 m 7 cantilever reinforced concrete beams 18 mm for every 3. 🕑 Reading time: 1 minute The design of reinforced concrete (RC) column is carried out by following certain procedures. The design of slabs for imposed loads and live loads is based on the type of the building. 525 mm. It also provides worked examples,. The imposed loads considered for various types of buildings can be. Grade 40 means that the yield strength is 40,000 psi and the code allowed strength is 20,000 psi. One reason is simple ease of construction. Garage floors that are at least six inches thick should have rebar because it provides the best support, but garage slabs thinner than that do not need rebar. That is the best way to have good concrete in such a place. Insert plate. c. To define design strip rules, click the Slab Design Rules button on the Data Entry toolbar. x 27 in. )(100)/(6 in. The top surface needs to remain wet while the curing process takes place. Watch on. Concrete Slab Rebar Spacing Guideline Report an Issue. 8. SLAB REINFORCEMENT SIZE REINFORCEMENT SPACING ANCHOR ANCHOR Cutting that rebar ain’t going to do shit, despite all the “engineers” comments to the contrary. Column spacings are 48 feet center to center. PSI means per square inch. A 6-mil (0. Build the wall full height, place concrete continuously in 4-foot lifts, and consolidate each lift. 34 inch (8. Rebar Spacing. Place rebar in a grid pattern with a spacing between bars of approximately 12 inches. unless otherwise noted, all slabs on grade are to be reinforced with 10mm bars at 400mm o. You can use regular fencing material with 2' x 4' or 2' x 6' mesh. Input the number of mesh in slab rebar. Floor Under Solids or Semi- solids and Single Axle load (15,000 lbs. 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. Types of Slab Construction ACI 360. Local code authorities often specify the type and placement of the reinforcement in a monolithic slab. Detail B: “Wrap and Snap Tie” (diagram upper right) is normally used when tying vertical wall reinforcement to hold the bars securely into. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. The main reinforcement of the slab panel “A” is marked as (1). 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. Second, the slab is allowed to elongate freely in the whole length of DFR, thus reducing its strain to the value. If too much water was. The specified compressive strength of concrete shall be as set forth in Section R402. normal rebar sizes (e. 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-. Essentially a early age concrete shrinkage problem (cement paste not reaching full strength/bond with aggregate and restraint on the concrete member due to rebar. Rebar size and spacing is dependent on the strength required. Larger areas, lower loads, and higher seismic zones. 3. In low- to. The more layers of rebar you have, the harder it becomes to properly vibrate the concrete. The openings are square in shape and range in size from 2 ft to 5 ft. Suresh, Professor, Civil Engineering Department, NIE, Mysore (Ph:9342188467, email: gss_nie@ yahoo. It may be desirable to tie and reinforce the new slab to the pre‐existing surrounding floor. 15. About Press Copyright Contact us Creators Advertise Developers Terms Privacy Policy & Safety How YouTube works Test new features NFL Sunday Ticket Press Copyright. In either case, blocks should be used under the. Unfortunately, rebar can cause extensive damage to construction tools if you are performing coring or concrete cutting work. Rebar in a concrete slab is crucial to any building. A slab with this joint spacing may be reinforced with bars (ASTM A 615, A 616, A 617, or A 706) or WWF (ASTM A 185 or A 497). Properly compacted sub-grades can reduce needs for reinforcement – as well. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. 3 Slabs-on-ground with turned-down footings. 1 in2. Horizontal rebar starting at 12 inches and at 18 inch intervals after to the top. 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. Number of Main Bars = Ly / spacing + 1 = (4000/150) + 1 = 27 nos. 25 inches (13 to 56 mm) in length. ( rS) Rebar Size (2,3,4,5,6,7,8,9,10,11,12,14,16,18,20) Use Size "0" for. 00 m to 6. 5 try 100 mm Dead load Slab weight = 2. 4. Content intended for mature audiences. Cracking can be the result of one or a combination of factors, such as drying shrinkage, thermal contraction, restraintRebar Development Length Calculator. In this article, we will examine the importance of reinforcing concrete with rebar and the proper steps. With our rebar calculator, you can eliminate. 50 m span joist, beams, & girder soffit under 3. In this video, you will learn the Spacing between the Main and Distribution steel bar. Free Reinforcement Calculator. 4m x. ACI 318-08. The procedure: Lay up the first 4-foot height of wall. 🕑 Reading time: 1 minuteEstimation of steel reinforcement quantity for concrete slab, footing and column, beams etc. Thank ForSubscribeLikesShare. Maximum spacing of bars for slabs • Main bars: 3h ≤ 400mm (in areas of concentrated loads 2h ≤ 250mm) • Secondary bars: 3. CONTROL JOINT SPACING. g. For slabs. 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. These provisions are not meant to prohibit the use. So, if we have used 12mm dia rebar in column maximum permissible spacing is 72mm and for 16mm dia longitudinal rebar the spacing is 96mm and so on. For slabs reinforced with rebar or wire mesh, this is considered fairly routine. The tendency is to lay rebar the way one’s. 5 m. 3rd. Minimum RCC beam size should not be less than 9″x 9″ (225MM X 225MM), with an additional slab thickness of 125 MM. and 6000 btu/hr heat loss in the second. dustrial floor slab. roof and floor inertia forces only. 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. In either case, blocks should be used under the reinforcement to keep centered within the concrete. The elevation to the top of the decking (bottom of the concrete waffle slab) for forming of the second floor above-grade slab is ___. 2 Spacing s of transverse barsUse min 3/8 inch 24 inch on center rebar (wired together) not mesh. This new slab design does not account for second floor installations or installations in a ground floor with a basement beneath. Consider. Two-story buildings require a minimum of 15-inch wide footings for 1,500 LBV soil. 18 bar 11/2″. Generally, rebar has an immense impact on concrete. 4 rebar in the lower part of the foundation. (as in example diagram) First, enter the concrete slab sizes: length = 6 m, width = 4 m. HollowCore floor slab systems provide construction flexibility, fire separation, vibration isolation, and the structural support required to span almost any challenge that large or small multi-deck buildings require. Purpose. com Round Measurements To 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. S. First year, cracked! The slab out the back door is 16 X 30, 4". #3 is most commonly used for patios and driveways, #4 for columns and walls, and #5 for foundations and footers. Learn the steps to pour a concrete floor inside an existing garage, house or shed. 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. Unless you are going to park a very large truck on the slab the 2'x2' oc #4 rebar is over kill IMHO. 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. 15% of the slab’s cross-sectional area), the spacing of tendons in at least one direction shall not exceed the smaller of eight times the slab thickness and 1. I have 10 in. Looking at the layout of the walls i think that the slab is 1 way spanning, but i would like to know what methods are available to check this. Lower composite deck-slab weight than 3WxH-36 for the specified concrete thickness 8 inch on center low flute spacing to allow for bearing wall studs to be at 16 inches on center Non-composite deck 7⁄ 8 inch depth, 32 inch coverage 2 foot to 7 foot Span Range No Acustadek® Options Good for short span conditions1. The maximum anchor bolt spacing shall be 4 feet (1219 mm) for buildings over two stories in height. 2L at the intermediate support. 8 ). This slab will have rolling fork lift loads. According to Indian standard rcc concrete roof slab thickness in residential building construction is 4 inches (100mm). A basic rule to follow when judging how deep a control joint should be is that it should be roughly 1/4 the depth of the concrete. Methods used for finding slab thickness varies for different types of slabs. Contact*: Severity*: Description*:Problem #3 – Shrinkage cracks that allow moisture to reach the rebar. ) slabs are plate elements used to form the floors of buildings. The current British Standard or guideline for tying reinforcement can be found in the document BS 7973-2:2001 (Spacers and chairs for steel reinforcement and their specification — Part 2: Fixing and application of spacers and chairs and tying of reinforcement). 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. If the floor is designed as a reinforced-concrete slab requiring rebar in the tension zone, the designer should specify the correct rebar position. on center, but this will depend on the structural design. Similar “uncontrolled” or “random. Rebar in a concrete slab reinforces it against weather and other external loads. I was thinking of the following: basement wall 8 inches thick 10 feet high backfilled up to 7 to 8 feet. For a 400 square foot slab, the man hours required to finish a two-car concrete garage slab is about 13 hours. 9 m in buildings with light wood-frame walls, floors and roofs, footing widths shall be determined according to. Unit 571 New Smyrna Beach, FL 32128 386-882-EZCE(3923). One Way Slab Bar Bending Schedule Calculation. Joint spacing that is greater than 15 feet require the use of load transfer devices (dowels or diamond plates). . square columns and concrete block wall supporting 10in beams @ 12ft on centers front to back. 1. in concrete slabs. In summary the design procedures for beams and floor slabs are similar with the following differences: (a) Minimum steel. 2 (ACI 318-11 Section 13. This is one of the types of concrete slabs. This is essential to know how much Rebar for the concrete slab is required. 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. The practice in which steel decks are used is known as composite floor decks. Often, concrete contractors don’t have solid runs of rebar anyway. Since this is a patio, you could use 6x6 10/10 wire mesh instead of the rebar. 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. For example, if a 6-inch-thick slab is used with #3 rebar at 18 inches on center, the percentage of steel for a 12-inch width would be: (0. Sand is filled at a height of 0. Rebar is tied together, using wire, to hold it in place. , interior beam dimensions = 14 in. SLAB MIN. ACI 360, "Design of Slabs-on-Grade", refers to this as a Type B slab. Concrete volume calculator plan view diagram. If two or more courts are constru c t e d , expansion joints should be prov i d e d midway between court s. Its primary purpose is to increase the tensile strength of the concrete, helping it resist cracking and breaking. Smaller projects like this usually have to sustain minimal loads and a lower tensile strength is more than enough. 25" 3,000 PSI / 28 Day Aging #6 Rebar: 12 in: D2-12C: 6. , the minimum footing width or area shall comply with Table 9. First, enter the concrete slab sizes: length = 6 m, width = 4 m. L. Ilang Araw Ang Pagbuhos Ng Simento? In this video, I'm sharing you the process of concrete pouring and sizes/spacing of rebars for the beams and slab concrete for the. The second table describes the negative (mid-span) moment demand and the bottom reinforcement. Modeling floor diaphragms. Inclined length = 0. And the rebar details of (1) is 10mmØ @ 8″ c/c. south d c rebar i 306" i #7,7/8" dia ---j r--rebar j. reqd identifying no. 1 -The no. This is for a building with 1st floor SOG, 2nd floor slab, 3rd floor transfer slab and wood framing above. #TwoWaySlab #Basic #ConstructionWatch Basic Concept with its Practical Application by Construction AnimationJoin as member to support the channel. Now, divide each measurement by the 14-inch spacing. 02 To control deflection, r. There are two types of Grade slabs: Usually after casting Plinth beams. * BEAMS SHEAR CONNECTORS (IF PRESENT) For M15 concrete, lever arm = 0. Sixteen gauge wire is used to tie. 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. In the case of the RCC slab, the maximum spacing between two secondary parallel wires should be 5D or 450 mm or whatever. Then use USDA NRCS. 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. 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. 00 m to 6. Multiple layers of c r ossing bars cause these pro b - l e m s . x 27 in. Two-Way Concrete Floor Slab with Beams Design and Detailing. 1. The typical depth for rebar placement for slabs is 2-4 inches. 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. 21 m 2. 8 inches. Subject: Re: Rebar in shop floor? Kingston,Mi. 1) provides the code basis. Consequently, building such slabs requires rebar spacing knowledge. 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. 20mm clear cover is sufficient for intermediate floor slabs, and 30mm clear cover should be provided for roof slab exposed to rain (c). First, it avoids that the column transmits to the slab a concentrated force, which would cause large stresses in the concrete slab and likely large damage. Joints are commonly spaced at distances equal to 24 to 30 times the slab thickness. spacing requirements and to repeat bar size and spacing as often as possible. Important Points. And the rebar. However, the boilers I have been recommended is the Electro boiler (30,000. , interior beam dimensions = 14 in. Place the second bar parallel to the first bar and 1 inch beyond (see Figure 2). • The slab is designed as a continuous slab, using theory of continuous beams (slabs), or the simplified ‘coefficient’ method (where applicable i. 59 per square foot. Pouring of floor 2's slabThe dead loads include the self-weight of the slab, floor finishes, walls, grills, etc. Rebar Grid Calculator. ˘ ˘ˇSpacing (Rebar) A-7 4-1/2” 4000 psi with 28 day aging #6 rebar 12 in. Workmanship and jobsite conditions. area elements and go to Assign > Shell/Area > Opening to create holes in the slab. If the floor is. 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. 5” long, are typically dosed at the rate of 60-68 pounds per cubic yard. The #3 rebar has a weight per length of 0. e. unless otherwise noted in plans or specifications, camber all r. 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. For areas where heavy vehicles or equipment may be placed, our independent third-party engineers will specify rebar reinforcement for concrete slabs on grade. 1. In the Flat-plate slabs, the main bars are provided in one direction at bottom of the distribution bar (in a shorter span). The mesh reinforcement in the slab is placed in the top with 1" covers. The Construction and Design of Concrete Slabs on Grade D. Next, you put steel rebar every 2 feet to strengthen the bond between the foundation and the footings. 24-foot joint spacing. The formula is, Number of bars = (length ÷ spacing) + 1. INSTRUCTIONS: Choose units and enter the following: ( L) Length of the slab. f. Rebar should be placed evenly throughout the project. the slab joint spacing should be the same as for an un-reinforced slab. In general, 6 inch (150mm) slab thickness is considered for residential and commercial buildings with reinforcement details as per design. 1d is for every 45° bend. It depends on what the 4-inch slab is being used for, as well as the location and soil type where it will be poured. NOTE: Section 1907. 1. For slabs of septic tanks, you usually use #3 and #4 bars. (Imagine you are walking around the slab) Hit Undo Last to Undo last side. This design is particularly effective for structures with consistent loads. Floor slabs can range from a simple residential basement slab to a heavy-duty industrial floor. Rebar is steel rods that typically run through slabs of concrete. For this case, the lift should not be installed without written authorization from theIt has stood up to some really heavy equipment for 25 years. ÞArranged bars should be strong enough not to deflect when a person steps onmaximum spacing of reinforcement in both directions. 8. 00 m to 6. , edge beam dimensions = 14 in. Figure B-10: Alternative Floor Slab Detail. A 6-mil. A rebar slab calculator is a tool used to determine the quantity and spacing of reinforcing bars (rebars) needed in a concrete slab. 2. It has Spanish language descriptions, labels and diagrams and it also has default units in the metric system (SI). Arivoli Jayaraman. Steel reinforcement bar size for footing of G+1/ 2nd floor building:- we will assume a structure of G+1 (two storey) residential building, using standard 4″ thick walls, according to general thumb rule, use of mesh bar of 12mm or number 4 (#4) size (diameter) of steel reinforcement as main and distribution bar (T12@6″C/C of Fe500) is most. However, if the concrete slab is meant to be the footing of a small structure, #4 rebar with a diameter of 1/2-inch should be used. 9. 15. It is possible to pour a concrete garage floor without installing rebar for reinforcement. Expansion grooves should be cut into the wet concrete to provide additional crack resistance. 2-25. t 12mm stirrups at 150mm ctrs Two terminated bars A A Elevation Section A-A Lsy. Fill in the price and single rebar length that you will buy at your supplier: rebar price = €2/m single rebar length = 6 m. a weak concrete has a compression. Because of this, the Building Code places limitations on the size and spacing of rebar in gunite & shotcrete. That is, there are breaks in the rebar along the runs. 2. What size rebar do I need for a 6 inch slab? The size of rebar needed for a 6 inch slab would depend on the specific application and requirements. For corrosion protection, however, most specifications require a minimum depth of concrete cover that usually ranges from 1 inch to 2 inches. For residential buildings, a live load of 2000 to 3000 N/m 2 is used as per Indian standards. Enter the slab dimensions, desired rebar spacing and the spacing from the edge to quickly find how to lay out the rebar grid. Mesh is set on chairs and placed over the entire floor area 1 to 2 inches above the top of the forms. The steel rods help reinforce the strength of the concrete slabs giving the structure a strong form. Labor Costs. , where a T-beam girder is supporting T-beams that in turn are supporting slabs, as shown in Figure 8. By: Olin Wade (Remodel or Move Stuff) The spacing of rebar in a slab depends on the purpose and size of the slab, as well as the climate in which it is being built. . ( W) Width of the slab. Concrete slabs: Contractors often use the 1/8 rule for determining the size of steel for a slab. Methods used for finding slab thickness varies for different types of slabs. AS3600-2009 P P Lsy. Note: Cut the two side form boards 3 in. (150 to 250 mm). 2—Slabs-on-ground 5. rebar spacing o. The floor system of the classroom shown in Figure 2. #5 bars are 5/8”. 7. The size of the rebar depends on the specific application, but typically #4, #5, #6, and #8 rebar are used. Fabrication of rebars consists of cutting to length and required bending. My understanding of slabs based on limited experience and a heck of a lot of reading here is:1. 74 sq feet 5000/2. Input all the dimensions in the input section of the above calculator. This wood sheeting, which should also be stronger than average, will act as a subfloor. Fiber length shall be 1 / 2 inch to 2. SLAB—Flat section of floor or roof either on the ground or supported by beams or walls. Ch. 3. Determine the rebar gauge. 5. Rebar Development Length Calculator is a web application that supports the design of post-installed rebar in concrete applications by calculating the necessary tension and compression development lengths required in accordance with ACI 318-19 / ACI 318-14. 3%. 5% reinforcement (reproduced here as Table 1). 23 Total factored load = 6. Also, a small hole in the concrete will be totally fine, given the fact that there is a rebar grid. 5 round bars, respectively, while. 5/16" 2" long bolts thru tight holes spaced 3" apart at the outer ends and then increasespacing by 1/2. MotorCity (Structural) 22 May 17 13:44. 4 × W1.