Q6: Does a rebar detailer use computer detailing
and/or computer-aided drafting programs?
A: Yes, most rebar fabricators employing detailers have a computer program
specifically as an aid to the detailer. Many fabricators have computer-aided drafting
programs which produce the placing drawings.
Q7: Does a rebar detailer require an engineering
degree?
A: No, a detailer is a highly trained technician skilled in interpreting data
presented on design drawings. Knowledge of structural design is not necessary to become a
good detailer.
Q8: Would it be better if a rebar detailer were a
graduate engineer?
A: With the premise that any higher education will improve the skills of a
person, the answer is yes, but as explained in the previous answer, it is not a required
qualification. A detailer relies on the architect/engineer to provide the data necessary
to properly detail the rebar.
Q9: Why are the detail drawings for reinforcing
steel called "PLACING DRAWINGS"?
A: As the term implies, "placing drawings" are used by ironworkers at
the job site to place (install) the reinforcing bars within the formwork. In preparing
placing drawings, detailers determine the quantity of bars from pre-established spacings,
bar lengths, bend locations, and bar positioning from instructions provided in the design
drawings and project specifications. While preparing the placing drawings, detailers also
prepare bar lists. The bar lists are used by personnel in a shop to fabricate the
reinforcing bars. It should be noted that "placing drawings" are not used in the
shop, per se. Thus, the term "shop" when applied to "placing drawings"
is erroneous.
Q10: Is there a standard type of placing drawing?
A: Each fabricator produces placing drawings that fit his particular requirements
and those of the placing contractors in the geographical area where the project is
located, but a standard for detailing reinforcement does exist. The title of the standard
is "Details and Detailing of Reinforcemenent4," and it has the designation ACI 315-80(86). The American
Concrete Institute publishes the ACI Detailing Manual4, which contains the 315
detailing standard. Illustrative placing drawings and other related information are also
included in the ACI Detailing Manual. The CRSI book, Reinforcing Bar
Detailing5, is based on the ACI 315 standard, and is used to teach trainee detailers.
Q11: What should a rebar detailer do when design
data are incomplete or conflicting or both?
A: The detailer should either directly or through the contractor establish a line
of communication with the architect/engineer in order to obtain the missing data or a
ruling as to which data are correct. The procedure which the detailer should follow is to
leave the data blank with a request that the data be supplied when the architect/engineer
reviews the placing drawing for approval. If the construction time schedule makes this
procedure too slow, the detailer should request that the missing or correct, data be
furnished via telephone or fax transmission. Any design information must be supplied to
the detailer, because detailers do not have the engineering expertise or design knowledge
necessary to make a judgment as to what may be required. Even if the detailer had some
engineering and design knowledge, the detailed structural analysis is usually not
available for review. In any case, engineering and design fall outside the scope of the
detailer's responsibility.
Q12: Most project specifications require that
placing drawings be submitted to the architect/engineer for approval prior to fabrication.
What is CRSI's opinion of this requirement?
A: CRSI believes that placing drawings should be submitted for review and
approval to the architect/engineer. Only the architect/engineer of-record has performed
the structural analysis and design and thus is in the best position to provide
interpretations and corrections to any and all details. Review and approval by the
architect/engineer-of-record allows corrections to be made prior to fabrication and
shipment of the material to the jobsite.
Q13: Doesn't the previous answer suggest that it
might be advantageous to have a registered professional engineer, employed by the
fabricator, "seal" the placing drawings?
A: Detailing is not a design function so the answer is no! The use of a
registered professional engineer's seal implies that the person was in responsible charge
of, not merely a contributor to, the work. The work in this context is the structural
analysis and design of the structure to resist the prescribed loads. A detailer is not
that person.
