ETL 1110-2-365
31 Aug 94
mixture. The study should be conducted according to
(1) Common analysis parameters. The analysis
the guidance in EM 1110-2-2000, Standard Practice
can be performed within ABAQUS by using a time-
for Concrete, and should be documented in a concrete
history analysis where the elements and loads are
materials design memorandum.
activated as prescribed by the proposed construction
schedule and the ambient temperature is modified as
(3) Construction parameters. A number of con-
construction proceeds through different seasons of the
struction parameters can affect cracking due to
year. The NISA should be performed using a set of
restrained volume change. They include: (a) lift
common parameters for the concrete, loading, and
height, (b) time between placement of lifts, (c) con-
ambient conditions. The common parameters are the
crete placement temperature, (d) use of insulation,
concrete's aging modulus and maximum adiabatic
and (e) monolith geometry including section thick-
temperature rise data, the extreme ambient tempera-
ness, monolith length, and location and size of inclu-
ture data, the incremental gravity loads, and the con-
sions such as galleries, culverts, etc. In addition, the
stant service loads. The aging modulus is represented
time of year that a monolith is constructed can be
by data reflecting the time variation of Young's Mod-
controlled if it has been determined by a NISA that a
ulus as a function of the age of the concrete and is
particular start date for construction is beneficial.
further discussed in paragraph A-3b(2)(a). The maxi-
Any construction requirements or restrictions identi-
mum adiabatic temperature rise reflects the tempera-
fied by a NISA must be clearly stated in the con-
ture rise within the concrete due to hydration of the
struction contract documents. When optimizing these
cementious materials and is further discussed in para-
construction parameters, due consideration should be
graph A-3b(1)(a). The extreme ambient condition is
given to common construction practices, economy,
defined in paragraph A-2c, the gravity loads are
and constructability.
described in paragraph A-5e(1), and the service loads
are described in paragraph A-2f.
A-2. Analysis Requirements
(2) Maximum and minimum material properties.
The terms maximum and minimum refer to a set of
a. General. Nonlinear incremental structural
bandwidths reflecting the uncertainty involved in the
analyses on MCS should be performed using material
use of these parameters as discussed in para-
property combinations of creep, shrinkage, and aging
graph A-1e(1)(a). Minimum refers to using the
modulus coupled with two dates for start of construc-
material test data multiplied by one minus the speci-
tion. The specified combinations of these parameters
fied decimal percentage, and maximum refers to
are only a minimum, therefore, engineering judge-
using the material test data multiplied by one plus the
ment should be used to ensure that all possible criti-
decimal percentage. The material test data bandwidth
cal combinations are included in the analyses for the
percentages for creep, shrinkage, and adiabatic tem-
evaluation and design of the structure. Deletion of
perature rise will be +/- 15 percent. These are the
any of the specified combinations requires consulta-
minimum accepted bandwidths and can be reduced
tion with and approval by the Structures Branch,
only after consultation with and approval by the
Headquarters (CECW-ED).
Structures Branch and Geotechnical Branch, Head-
quarters, (CECW-ED and CECW-EG).
b. Material property combinations. The mini-
mum combinations of material properties for the
purpose of analyzing and evaluating a MCS are
shown in Table A-1.
Table A-1
Material Property Combinations
Adiabatic
Young's
Temperature
Mechanical
Modulus
Creep
Shrinkage
Rise
Loads
1
Aging
None
None
Maximum
Gravity + Service
2
Aging
Minimum
Minimum
Maximum
Gravity + Service
3
Aging
Minimum
Maximum
Maximum
Gravity + Service
A-9
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