Placing Drawings – the Detail Drawings for Reinforcing Bars In
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ENGINEERING ETN-C-4-15 Placing Drawings – The Detail Drawings for Reinforcing Bars in Site-Cast Reinforced Concrete Construction Introduction Placing drawings are not used in the fabricating shop, per se. Thus, the generic term “shop” when The terminology regarding the detail drawings for applied to the detail drawings for reinforcing bars in reinforcing bars in site-cast reinforced concrete con- site-cast concrete construction is extremely inappro- struction is often misused in contract documents* priate. and is not an accurate description of the detail draw- ings. The issue of terminology is real. It is not a trivial Responsibility Issues nor a scholarly matter of semantics. Rather, the inap- propriate “labeling” of the detail drawings for rein- Responsibility for the preparation, review, and ap- forcing bars can result in: proval of placing drawings is established in the ACI detailing standard and in the ASCE quality manual. • Unnecessary added costs to the Reinforcing Bar Fabricator, which are ultimately passed on. ACI 315 Detailing Standard. The USA consensus standard for detailing reinforcing bars for site-cast re- • Issues regarding responsibility and ethics. inforced concrete construction is promulgated by the • Time delay due to drawing submission proto- American Concrete Institute: “Details and Detailing cols. of Reinforcement (ACI 315-99)”. ACI 315 clearly addresses the responsibilities of the Objective of This Report Architect/Engineer regarding placing drawings: The aim of this report is to: “The responsibility of the Architect/Engineer is to furnish a clear statement of design require- • Define and describe “placing drawings” - the ments to the Detailer. The Architect/Engineer’s detailed drawings for the reinforcing bars in site- project specifications or structural drawings cast reinforced concrete construction. must not merely refer the Detailer to an ap- • Dispel the notion that “one size fits all” in the plicable building code for information to use in descriptions of the detail drawings for construc- preparing the placing drawings. Instead, this in- tion materials and products. formation shall be interpreted by the Architect/ Engineer and shown in the form of specific de- What are Placing Drawings sign details or notes for the Detailer to follow. Where omissions, ambiguities, or incompat- Placing drawings are working drawings akin to erec- ibilities are discovered, additional information, tion or assembly type drawings, instructing the field clarifications, or corrections shall be requested Ironworker (Placer) where to place the reinforcing by the Detailer and provided by the Architect/En- bars within the formwork. Placing drawings may gineer. The Architect/Engineer should require in also indicate the bar support layout and a placing se- the project specifications that placing drawings quence, thus facilitating the efficient installation of be submitted for approval.” the reinforcing bars. Regarding the Detailer’s responsibility, ACI 315 Placing drawings are prepared by Detailers, trained Technical Note Technical states: technicians who are extremely proficient in interpret- ing the structural information shown by the contract “The responsibility of the Detailer in preparing documents. At no time does a Detailer make an engi- placing drawings is to carry out all instructions neering decision. In fact, in today’s litigious society, a on the Contract Documents. “ Detailer would be foolish to accept this responsibility. ASCE Quality Manual. ASCE’s Manual No. 73, Qual- Figure 1 shows an example of a placing drawing. ity in the Constructed Project, addresses the role of placing drawings for reinforcing steel in cast-in-place A Detailer prepares a list of the reinforcing bars that concrete construction. Chapter 17 of the manual is are shown on the placing drawings. A bar list is a list- titled Construction Contract Documentation and Sub- ing of reinforcing bars making up a bill of materials. mittals. Article 17.3.8 (Placing Drawings for Concrete The bar list contains the quantities, sizes, lengths, Reinforcing Steel) states in part: and bending dimensions of the reinforcing bars. These lists serve several purposes. The Fabricator “ ... The design professional has authority and uses a bar list for shearing and bending, tagging, responsibility for overall design of the complet- shipping, and invoicing. The Ironworker Foreman and ed structure and for the review and approval of the placing crew use a bar list for checking delivery the placing drawings for conformance with the quantities, sorting bundles of bars in the job-site lay- project design concept and the information in down area, and hoisting of proper bundles to the the construction contract documents. placing area. The constructor and subcontractors have re- Figure 2 shows an example of a bar list. sponsibility for preparing the placing drawings, providing the materials specified, and complet- ing the fabrication and construction process. This work is carried out in accordance with the construction contract documents, approved *See the Terminology section for definitions of cer- placing drawings, and accepted industry stan- tain terms used in this report. dards. the Architect/Engineer regarding the structural detailing of anchorage or embedment lengths and splices of reinforcement. In Chapter 26 of the Code, Section 26.6.1.1 states: “Design information that the licensed design professional shall specify in the construction documents: • Type, size, location requirements, detailing, and embed- ment length of reinforcement • Location and length of lap splices • Type and location of mechanical and welded splices” This point is further emphasized in Section 26.6.2.2(c), which states: Figure 1 - Example of a placing drawing “Splices in reinforcement shall be made only as permitted in the In most cases, placing drawings for reinforcing steel in cast-in- construction documents, or as authorized by the licensed design place concrete do not need design services and it is not neces- professional.” sary or appropriate for the contract documents to call for certifi- In his presentation at the October 1998 PCI Convention and Exhibi- cation by a licensed engineer. For post-tensioned, pre-stressed, tion, Norman L. Scott, an eminent Structural Engineer, included com- cast-in-place concrete structures, the design professional may ments on the issue of design responsibility. Mr. Scott was actively in- delegate certain design activities to ... “ volved with the ASCE Committee on the development of Manual 73 Design Responsibility and the ACI Board Committee that prepared “ACI Guidelines for Au- thorities and Responsibilities in Concrete Design and Construction”. Structural Detailing of Reinforcement. Proper structural detailing Regarding placing drawings, Mr. Scott stated: of reinforcement is critically important to attain the desired level of performance of reinforced concrete structures. Adequate anchorage “. The reinforcing steel fabricators who supply reinforcing bars or embedment lengths and splices of reinforcing bars are crucial. for cast-in-place concrete say they never do any design work and, therefore, it is not necessary to sign their submissions, Since the structural details of reinforcement are critically important, which they prefer to call placing drawings. The ACI responsibility it is unrealistic for the Architect/Engineer to require or expect the De- committee looked at this practice very carefully and concluded tailer to perform the structural detailing - the Detailer is not qualified that they [the reinforcing steel fabricators] are right. There are to do so. essentially no reinforcing bar suppliers who do design work; The ACI 318 Building Code properly assigns certain responsibilities to they just do the detailing. “ 2 Placing Drawings - The Detail Drawings for Reinforcing Bars in Site-Cast Reinforced Steel Construction [ETN C-4-15] 2/10/2015 09:20 AM Release Details Page: 1 of 1 Lengths in Imperial Job#: ET859933 Asby Laboratories Weights in Imperial (lb) Cust#: 584929 Duckworth Constrution Co. Release: 01000 Basement ELevator Pit Bid: 001 (HOTEL BUILDING) MTR: Yes Sac: 650 MISC., PITS Lab: N/A Code: Cust Late Order (Bill Adj: 1) Status: Fabbed Item# Type Oty Part Grade TotLgt Mark Bend A BC D E F GH KRJ O Weight Color Remarks Sep. Sep. Rmk On Rmk On Bundle? Tag? Bar List? Tag? FOUNDATIONS x x Item# Type Qty Part Grade TotLgt Mark Bend AB CD EFGH KRJO Weight 0002 Str 17 6+ A706/ 16 -10 430 0003 Str 17 6+ A706/ 16 - 9 428 0004 Str 4 8+ A706/ 16 - 0 171 0005 Str 4 8+ A706/ 17 - 9 190 0006 Str 4 8+ A706/ 19 - 9 211 0007 Str 4 8+ A706/ 22 - 3 238 0008 Str 4 8+ A706/ 25 - 0 267 0009 Str 11 5+ A706/ 16 - 6 189 0010 Str 12 6+ A706/ 15 - 6 279 0011 Str 12 6+ A706/ 16 - 6 297 1 3 3 0012 Lig 30 4+ A706/ 7 - 3 /2 4A21 26S 2 - 0 1 - 2 /4 0 - 10 1 - 2 /4 2 - 0 146 3 3 0013 Hea 44 6+ A706/ 9 - 0 /4 6A60 2 1 - 0 7 - 0 /4 1 - 0 599 1 1 1 1 1 3 0014 Hea 12 8+ A706/ 36 - 4 /2 8A34 3 1 - 4 9 - 11 /2 13 - 9 /2 9 - 11 /2 1 - 4 7 - 1 /4 6 - 11 /4 30 - 5 1165 1 3 3 3 1 3 0015 Hea 12 8+ A706/ 36 - 1 /4 8A35 3 1 - 4 9 - 11 /4 13 - 5 /4 9 - 11 /4 1 - 4 7 - 1 /2 7 - 0 30 - 1 /4 1157 0016 Hea 20 8+ A706/ 16 - 0 8A36 17 8 - 0 8 - 0 854 282 - 66 - Hash Totals -1 - 0 19 - 8 27 - 24 26 - 24 19 - 24 4 - 8 1 - 0 14 - 213 - 11 0 - 00 - 0 60 - 6 Size Total # Total Total Stock Straight Straight Heavy Heavy Heavy Light Light Light Medium Medium Spiral Spiral Thread Thread Pcs Weight Weight Pcs Weight # Pcs Weight # Pcs Weight Pcs Weight Pcs Weight Pcs Weight CRSI Technical Note Technical CRSI Rebar-Black A706/6 4/13 Bar 1 30 146 0 0 0 0 0 0 1 30 146 0 0 0 0 0 0 5/16 Bar 1 11 189 0 11 189 0 0 0 0 0 0 0 0 0 0 0 0 6/19 Bar 5 102 2033 0 58 1434 1 44 599 0 0 0 0 0 0 0 0 0 8/25 Bar 8 64 4253 0 20 1077 3 44 3176 0 0 0 0 0 0 0 0 0 Size Tot: 15 207 6621 0 89 2700 4 88 3775 1 30 146 0 0 0 0 0 0 RptTot: 15 207 6621 0 89 2700 4 88 3775 1 30 146 0 0 0 0 0 0 3 Figure 2 - Example of a bar list Approval of Placing Drawings Exchanging drawings electronically, as CAD or PDF files, is a way to save time and improve the accuracy of placing drawings.