Chapter Two The items discussed in this chapter are outlined below. Fabrication Bend Class Typical Bar Bends Bar Marks and the use of MK symbol Drafting (CAD) Standards CAD Software Contract or Working Drawings Lettering Styles Title Blocks Paging Delta or Revision Block Revisions Bar Listing and Releases Archival Fabricating Tolerances Barlines Bulletins ALL ABOUT FABRICATION, DRAFTING (CAD), BAR LISTING AND TOLERANCES By Amadeus (Mady) Magpile, President and CEO INTRODUCTION This is second in a series of articles outlining the Manual of Standard Practice, Estimators and Detailers of Barlines adhere to in the practice of Reinforcing Steel Engineering in the Philippines. In this chapter we will point out the use of ACI/CRSI Typical Bar bend Types, Tolerances in Fabrication and Minimal Bar Supports. 2.01 FABRICATION BEND CLASS The reinforcing steel fabricators, needed to distinguish each bent types in fabrication according to their cost accounting and time study. They needed to properly track down each particular cost associated to bending. Straight cutting or shearing was always considered the least expensive to process. Bend Types were separated into three classes according to fabrication productivity as follows: 1 1. LIGHT BENDING, which applies to: a. A bent 10 or smaller bars. b. All Stirrups and Ties, no matter what bar size.
c. All #12 to #50 which are bent at more than six points in one plane. d. All bars bent in more than one plane (unless classified as Special bending. e. All one plane radius bending with more than one radius or a combination of a radius and other type of bending 2. HEAVY BENDING, which applies to: a. All #12 to #50, which are bent at no more than six points in one plane b. All #12 to #50 bent with a single radius. 3. SPECIAL BENDING. a. All bending to special tolerances, such as bending for precast units. b. All radius bending in more than one plane c. All multiple plane bending containing one or more radius bends Fabrication cost in the Philippines is all lump into one unit price per kilo no matter what bend class. This practice tends to put fabrication lagging behind installation. No one wanted to get stuck with fabricating ties and stirrups, which unfortunately account for the most quantity in a job. Classifying the bend into productivity classes makes the fabrication on an even keel to that of installation. 2.02 TYPICAL BAR BENDS In order to list the various types of bent bars in a Bar Bending Schedule, it is necessary to have the stick diagrams of the bars with the lengths of each portion of the bars be designated by letters. Such was the recommendations of both the American Concrete Institute (ACI) and the Concrete Reinforcing Steel Institute (CRSI). Both agreed on a Typical Bar Bends and assigned a Type of each one. Here are some of the rules or characteristics of the Typical Bar bend Types 1. Each Bar Bend Types are limited to 12 designated letters as shown below. Type A B C D E F/R G H J K O 2. All Dimensions are out to out of bar except A and G on standard 180 o and 135 o hooks. 3. The total length of the bar is equal to the sum of letters A thru G only. 4. Dimensions A and G are reserved for Standard Hooks. However it is sometimes used to show dimensions smaller than standards. 5. The letters F and R never appear together in a Type. 6. The dimensions H, J, K and O are controlling dimensions outside the bar. Almost always they refer to Height, Hook Width, Base and Overall Dimension, respectively. 7. J dimensions on 180 o hooks to be shown only where necessary to restrict hook size, otherwise standard hooks are to be used. 8. Where J is not shown, J will be kept equal or less than H on Types 3, 5, and 22. Where J can exceed H, it should be shown. 9. H dimension stirrups to be shown where necessary to fit within concrete. 2
10. Where bars are to be bent more accurately than standard fabricating tolerances, bending dimensions which require closer fabrication should have limits indicated. 11. Unless otherwise noted, diameter D is the same for all bends and hooks on a bar (except for Bend Types 11 and 13). 12. Detailing Software knows the Bend Class of each Bend Types. 13. While not required in detailing, manual estimating requires that bend bars be classified as or null entry for Straight bars, H for Heavy bent bars, L for Light bent bars and S for Special bent bars in order for their estimate to be properly priced. 14. The use of all bends in a type is not mandatory. One or more bends can be eliminated in a type, however choose the type that will allow the least number of bends to eliminate. 15. The common practice when choosing between similar Types is to choose the types with the least number of dimensions. For example, if you need B, C and D from either Type 3 or 5, pick Type 5. 16. The numbered Types are mostly Heavy Bent Bars and the Types with a prefix S and T are mostly Stirrup and Ties. Do not use Type 17 for S10, because the former will be bent around a larger pin than the latter. 17. Type X is a spiral. The Nominal Length of the bars is equal to the total number of Turns multiplied by the circumference of the spiral. 18. A Detailer can make his own Bend Type, if it is not in the Typical Bar Bend Chart, as long as he maintains the above rules and he designated the type as H, L or S, thus: Type H100, Type L201 or Type S325. The practice is to maintain the type of each job. 19. Dimensions in bars shall be rounded to the nearest 5 mm. To match the calibration of fabricating equipment. 20. The least amount of bar marks is ideal in a given release. Bars that are exactly alike but with different bar marks slow down Shop Production because the machine is forced to process them separately. Consider marking bars the same if the difference in dimensions is within a few millimeters. For example: A dowel that is 300 x 900 is made the same as dowel that is 295 x 900. The added material is offset by savings in field and shop labor. 21. For bend types, where there is a choice in dimensioning bends, dimensions in the way that will require the least amount of work in the shop. 2400 900 900 685 2400 1825 685 A B 1825 3
Some Detailers will detail as shown on B simply because this is the way the bar appears in the structure. It is obvious that it would be easier to fabricate as shown in A. 22. Be mindful of the effect of a bend in wall or slab thickness or stirrups EARS meeting each other and bundled bars within the EARS of ties and stirrups. Check the following sketches. 23. While types T2 and T4 are exactly the same, label wise and shape wise use type T4 for diagonal ties in a square or rectangular columns and square ties in a circular columns. Type T4 provides the detailer the use of H and K to arrive at the B, C, D and E dimensions. In any detailing software entering H and K is all that is required. Because of the radius of the bend, calculating for the hypotenuse will not be correct as a bar dimension. Check it out. 4
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The Typical Bar Bends are attached at the end of this chapter as loose leaf pages. 2.03 BAR MARKS and the use of MK symbol Barlines standard practice, following that of CRSI and ACI is to assign bar marks for all bent bars but not of straight bars. The bar marks may be strictly numeric or alpha numeric. Alpha numeric is preferred. In alpha numeric the letters I, O, Q, and Z are never used. These letters can easily be mistaken for the number zero, one and 2. Example Bar Marks 860 Mk 16C08 @ 300; 860 Mk 16008 @ 300 The Mk is not part of the mark. It is used between quantities and actual bar mark. The first one two digits denotes the bar size, followed by an Alphabet in sequence or zero (0), if strictly numeric, and then followed by sequential number. The Letter at times used to identify where the bars will be used. For example, B for Beams, C for Columns, F for Foundation, etc. Moreover, the letters are used sequentially A, B, C, D to avoid having mixed use bars at the jobsite, such as 1 st floor and 2 nd floor Columns. 6
2.04 DRAFTING (CAD) STANDARDS Barlines Rebar Detailers shall comply to the following proven practices: No lines shall cross a text. If a text is written over a line break the line and allow the text clear path. Provide a Key Plan with proper orientation to North. Show Grades of Steel and Corrosion protection if any. Show Pour Joints, Expansion Joints and pour sequence. Be mindful of Male and Female pour. Provide adequate scales. Not to large or too small. Compose your drawings and provide balance. Avoid overcrowding but planning ahead. Simplify your presentation. Avoid looking too busy or too cluttered. Placing drawings does not require hatching or concrete pot marks. Take advantage of symmetry. Consider gathering TYPICAL details into your personal library. Show actual length of splice, not just bar diameter ratio. Always show clearances to the bars. If possible show Bend Schedule in the same page as the details or avoid to many pages between details and Bend Schedule. Cloud a particular detail to draw attention to reviewers. For example: Dimension that need verifications. Clearly show the number of times a detail repeats, thus 5X, 10X, 3X. Do not change the Engineer s assigned marks. Renaming a Column or a Beam, beyond a mere subscript addition is not acceptable. Example: A beam marked by the engineer as Beam B 1 can be renamed B 1A or B 1B to distinguish one against another, but it cannot be renamed B 10. Always provide standees, spreaders, support bars and templates. If required list accessories. Show dimensions of Footings, Cols, and beams: thickness of walls and slabs. Show elevation at top and bottom of walls and columns. Show dimensions between grid to grid. Show clearly starting point, spacing and end point of ties and stirrups. Show Beam and Slab bar endos and end stagger dimensions when it occurs. All bars in a given barlist or bending schedule must be shown and located in placing drawings without exception. Show extension and dimension of all dowels Provide Opening Trim Bars. Provide corner and re entrant bars. Properly call out Mechanical Couplers by its trade name. 7
Call out quantities, bar sizes, lengths or bar marks. A Rebar Detailer will show all these, while a Structural Draftsman does not need to. Distinguish your work from Structural Drafting. Ideally each bar shall be shown in a plan view, section and elevation to fully discern its 3 dimension location in concrete. However, on occasion a bar shown in only 2 views will be adequate. 2.05 CAD SOFTWARE Barlines Rebar Detailers shall detail using AutoCAD, AutoCAD LT, Microstation or IntelliCAD. The paper size for full size printing shall be D size, 22 x 34 and for half size printing it shall be Ledger size, 11 x 17. These two sizes are easily folded at the jobsite to 8 1/2 x 11 paper size for filing. A Placing Drawing is like a painting a piece of art. Ever notice why some drawings are pleasing to the eye than others, the better drawings combine composition, proper use of scales, concise text and serve to convey a blueprint of a building. These are all applied whether a detailer uses a CAD or does his work manually. No CAD software can do these automatically. 2.06 CONTRACT OR WORKING DRAWINGS Barlines shall require both Architectural and Structural drawings to do their job. A complete set of drawings and specifications will be requested on large jobs. At the completion of the job all working drawings and placing drawings shall be gathered and scanned for archival purposes. The electronic files shall be copied into a CD or DVD and surrendered to the Office Manager for safe keeping. 2.07 LETTERING STYLES Lettering Style shall be in uppercase, slanted Gothic for rebar and dimension callouts, notes and schedules. Vertical Gothic shall be used blocks and detail titles. Lettering height at full size printing (D size, 22 x 34 ) shall be 3 mm. for dimensions and bar callouts with leaders. Title blocks and Detail titles shall be 7 mm. 8
2.08 TITLE BLOCK Detailer shall use Barlines Standard Title Block. Each box shall be filled in with precise minimum information as shown below. DRAWINGS FOR: LEVEL 3, POUR 3 SLAB N S BOTTOM JOB NAME UNITED REGIONAL HEALTH CENTER CONTRACTOR BAYANIHAN GENERAL CONTRACTING JOB NUMBER shall be our customers Job Number if available, otherwise Barlines own Job Number. BY shall be the Detailers own name. DATE shall be the date a set of drawings for submittal are completed. Drawings are submitted in sets. Each set shall have the same date. 2.09 PAGING Each drawing number shall begin with a capital letter, describing the following categories: F C W P B S Foundation including slab on grades; also site work. Columns, conventional or ductile frame. Walls; concrete and masonry, shear wall, shotcrete walls and others. Tilt up Panels only. Beams and Girders; conventional and post tensioned Slabs; flat slab, one or two way slabs, conventional and post tensioned On a small job, requiring no more than 20 pages to complete the detailer shall consider: R All rebar The capital letter shall be followed immediately, without a hyphen with a sequential number. Avoid adding a suffix such as F1a, F1b. Duplicate numbers in the same category are not allowed. 9
2.10 DELTA OR REVISION BLOCK Inside the Delta or Revision Block: the first submittal shall be marked with revision A and dated. Each subsequent submittals until approval shall be marked B, C, and D and so on and dated. When the drawings have been approved the block is cleared of all entries and the first line is marked 0, the current date and the note APPROVED FOR CONSTRUCTION. Any subsequent revisions after approval shall be marked 1, 2, 3 and so on, dated and reason noted. Rev DATE A 09/24/07 1 ST SUBMITTAL B 11/20/07 2 ND SUBMITTAL Rev DATE 0 12/03/07 APPROVED FOR CONST 2.11 REVISIONS ALL REVISIONS AFTER APPROVAL ARE BILLED BY THE HOUR. Please keep track and report all hours spent during the revisions. Also, when the drawings has been approved, inside the drawing box, in a prominent place a box saying in bold letter APPROVED FOR CONSTRUCTION shall be place. Barlines shall assume approval if submittals are marked: APPROVED NO EXCEPTIONS APPROVED AS NOTED or EXCEPTIONS NOTED Barlines will resubmit if submittals are marked REVISE AND RESUBMIT INCOMPLETE/RESUBMIT NOT APPROVED OR NON COMPLIANCE 10
2.12 BAR LISTING and RELEASES Bar Listing is the process of sorting from the Placing Drawings what is needed to be delivered to the jobsite. If the Detailers preplanning went according to his plan, bar listing may simply be all of the items in the Placing Drawings. But that is always the case. At times, the jobsite may require certain items in the Placing Drawings be delivered earlier than the rest. While Placing Drawings are for the ironworkers in the field Bar Lists are for the shop men in the Shop. Barlines shall bar list only upon approval of Placing drawings or when instructed to by customer with or without approval. Bar List must be separated by Release no. A release cannot be more than a truckload (20,000 kilos). A release cannot be separated into two trucks. A Release sequential numbers denotes priority at the jobsite. Duplicate Release in a job is not allowed. The Fab Shop will automatically put smaller number releases over higher number releases, so that at unloading, the bars needed first are the first unloaded. Subscripts are allowed in release numbers. A Sample Release Log Book Job/Rel# Material For Grd Ord Date Ship Date Tot Mass By B220 001 Col Pads 415 05/02/11 05/09/11 5500 BP B220 002 Columns, 1 st Lift 415 05/02/11 05/09/11 10800 BP B220 003 Cont Wall Ftgs 415 05/02/11 05/09/11 3500 BP B220 004 Columns, 2 nd 415 05/02/11 05/11/11 16400 JA B220 005 Slab on Grade 275 05/04/11 05/11/11 2800 JA B220 006 2 nd Floor Beams 415 05/11/11 05/20/11 9150 BP Ship only the required material; hold stockpiling on jobs to a minimum. Keep different grades of steel on separates releases, unless Barlines makes other provisions for handling of this problem Rebar for separate areas should be put on separate releases, so that each release can be stockpiled close to where it will be used. This takes the color coded tags to maximum efficiency. 2.13 ARCHIVAL Consult with your Supervisor for the current practice of storing all files generated or issued to you on all all jobs. Such files are: Contract Drawings, Specifications, Addendums, RFI s (Request for Information), Detailing Sheet, Placing Drawings and Bar Lists. DO NOT DISCARD A FILE. 11
2.14 FABRICATING TOLERANCES All fabricating tolerances shall be in accordance with CRSI Figures 7 3 and 7 4, unless otherwise agreed to by the Buyer and Seller. Rebar Detailers shall be mindful of fabricating tolerances when bars are in a confined space. A detailer who is well versed o tolerances and details accordingly is usually able to get by without ever needing a HOLD dimension. Putting a HOLD dimension on a bar dimension is very expensive practice. At our shop, the fabrication of type 2 bars with a length of 7800 mm, which normally is one man operation, becomes a two man operation if a HOLD is placed on the belly or B dimension. In other words, the fabrication cost practically doubles. This is not to say, however, that the practice does not have any merit. 2.15 BARLINES BULLETINS Throughout the year Barlines will be sending out bulletins to supplement our Manual of Standard Practice, pertaining advances in technology, changes in current local practices, and learning from our mistakes. Barlines strongly suggest reading and collecting these bulletins as they are issued in a folder for reference at any time and to comply without exceptions. Team Captains are urged to make sure there team members all have such folders. Ignorance of these bulletins will not be acceptable. 12