Grade 80 Reinforcement in Special
Moment Frames or Shear Walls
Q. Does the new ACI 318-19 Code1 allow the use of
Grade 80 steel for earthquake-induced moment,
axial force, or both, in special moment frames or
A. ASTM A706 Grade 80 deformed reinforcement is
permitted to be used for design of special moment
frames and special structural walls under
conditions in Section 22.214.171.124 of ACI 318-19. However,
ASTM A615 Grade 80 deformed reinforcement is not
64 SEPTEMBER 2019 | Ci | www.concreteinternational.com
permitted in special seismic systems. Refer to Sections
126.96.36.199 and 188.8.131.52 in ACI 318-19, as well as the
accompanying commentary sections and references, for
in-depth discussions on this topic.
1. ACI Committee 318, “Building Code Requirements for Structural
Concrete (ACI 318-19) and Commentary (ACI 318R-19),” American
Concrete Institute, Farmington Hills, MI, 2019, 623 pp.
Estimating Service Life of
Environmental Concrete Structures
Q. As part of an asset management project, I’m
trying to put life expectancy numbers to reinforced
concrete sanitary structures. However, I’m having
no luck finding reference materials that contain this
information. Can you point me to any publication that
discusses the life expectancy of reinforced concrete structures
(sanitary or other)?
A. Regarding environmental concrete structures,
General Commentary Section of ACI 350-06
states: “When all relevant loading conditions are
considered, the design should provide adequate safety and
serviceability, with a life expectancy of 50 to 60 years for the
structural concrete. Some components of the structure, such as
jointing materials, have a shorter life expectancy and will
require maintenance or replacement.”1
If you are trying to predict the remaining life of an existing
structure and it was designed to the ACI 350 Code, you can
use that statement to make a simple estimate. Note, however,
that the ACI 350 Code covers a wide set of variables, and the
life expectancy will depend on the severity of the environment
as well as whether a maintenance program was in effect
during its service.
If your project requires a more accurate determination of
the life expectancy for new concrete structures or remaining
service life of existing concrete structures, service life
prediction models will need to be employed. Such models are
discussed in ACI 365.1R-17,2 along with economic
considerations. There are many ways to achieve short- or
long-term performance, so designs may vary significantly to
achieve the same objective. Many require detailed
maintenance plans that put some of the cost in the future,
which an agency may or may not have budgeted.
ACI Committee 365, Service Life Prediction, is currently
working on a standard of practice to make it easier to compare
longer-term designs; however, it may be several years before
that publication is available.
1. ACI Committee 350, “Code Requirements for Environmental
Engineering Concrete Structures (ACI 350-06) and Commentary,”
American Concrete Institute, Farmington Hills, MI, 2006, 485 pp.
2. ACI Committee 365, “Report on Service Life Prediction
(ACI 365.1R-17),” American Concrete Institute, Farmington Hills, MI,
2017, 56 pp.