CRSI |
ENGINEERING
DATA REPORT NUMBER 38 |
REBAR DETAILING PLACING DRAWINGS AND APPROVALS |
 A
SERVICE OF THE CONCRETE REINFORCING STEEL INSTITUTE
933 N. Plum Grove Rd., Schaumburg, Illinois 60173-4758 |
INTRODUCTION
The investigations into the collapse of the mezzanine level walkways of the
Kansas City Hyatt Hotel in 1981 uncovered the critical relationship between steel frame
design drawings and structural steel shop drawings. Since then many architects/engineers
and agencies have taken the point of view that structural steel shop drawings and
reinforcing steel placing drawings are the same in nature, scope, and purpose. This
correlation is not true.
The ASCE Manual1, "Quality in the Constructed Project", has
clarified the difference between the two types of detail drawings. In Chapter 16 of the
ASCE Manual, the two types of detail drawings are called "Shop Drawings for
Structural Components" and "Placing Drawings for Concrete Reinforcing
Steel".
This report explains the primary function of -a rebar
placing drawing, defines the qualifications of a rebar detailer, describes how a placing
drawing is produced, and clarifies the responsibility of a fabricator of reinforcing
steel.
Q1: Who is a "DETAILER", and what does
that person do?
A: A detailer is usually an employee or subcontractor of a fabricator. A detailer
uses design information shown on the design drawings and project specifications to
"detail" or list all the reinforcing steel items required for a particular
portion of the structure. These individual rebar items are then listed, or scheduled, or
shown by plan or section on a detail/placing drawing.
Q2: What design information is required by building
codes?
A: The ACI 318 Building Code2 states in Chapter 1, Section 1.2.1, the general requirements
governing the design. Specifically, with regard to reinforcing bars, the Code states (in
part) that the design drawings shall show* size and location of all structural elements
and reinforcement"; "anchorage length and location and length of lap
splices"; and "type and location of welded splices and mechanical connections of
reinforcement".
Q3: Why is it necessary "TO DETAIL"
design information?
A: Design information normally will be specific with regard to the dimensions of
structural members and systems, the quantity or spacing of reinforcing bars, and bar
sizes, but general as to bar lengths and bar configurations. This general or typical
information is not specific enough to be able to cut to length, fabricate, ship, and place
(install) reinforcing bars directly from the design drawings. Hence, the requirement that
detail/placing drawings be furnished.
Q4: What am the qualifications of a rebar detailer?
A: As a minimum, a person with a high school education, with good mathematical
and visual skills would qualify for training as a rebar detailer. Any additional education
in computer sciences, drafting or engineering would enhance the qualifications.
Q5: How are rebar detailers trained?
A: Detailers are trained by attending a vocational technical school, by using the
CRSI Detailer Training Progran3 with the guidance of a fabricator's staff, by "hands-on"
training under the supervision of an experienced rebar detailer, or by a combination of
all three methods.
© Copyright 1993 by the Concrete Reinforcing Steel Institute
