ETL 1110-2-355
31 Dec 93
2-4. Foundation alternatives. The decision
nonlinear response could be acceptable depending
upon the extent and duration of the response, redun-
whether to have a pile-founded or soil-founded
dancy of the structure, potential damage implications,
U-frame lock must be based on numerous consider-
and probability of occurrence. Decisions on accept-
ations: erodibility of foundation, potential for scour,
able nonlinear behavior must be coordinated with
factor of safety against flotation during dewatering of
CECW-ED.
the lock, differential movements between monoliths,
soil-bearing capacity, sliding stability for large unbal-
3-2. Stability. Stability criteria are applicable to
anced loads, the level of seismic activity, project
layout, and cost. The type of foundation will affect
soil-founded locks and include safety requirements
the analysis methods and monolith geometry.
against sliding, flotation, and overturning.
2-5. Two-dimensional versus three-
a. Sliding. Sliding stability is defined and cal-
dimensional behavior. U-frame lock monoliths
culation methods are shown in ETL 1110-2-256, and
EM 1110-2-2502.
can be categorized as two- or three-dimensional
behavior. The behavior of a monolith is dependent
b. Flotation. Floatation stability is defined and
upon both geometry and loading. Gate monoliths act
calculation methods are shown in ETL 1110-2-307.
three dimensionally due to loads on the gates which
Some provisions that are unique to U-frame locks can
act in the longitudinal direction. Even though the
be found in other guidance.
behavior of a gate monolith may be three dimens-
ional, it is possible to analyze a gate monolith by
c. Overturning. Overturning is not usually
using a set of two-dimensional analyses to capture the
critical for U-frame lock monoliths because of the
three-dimensional behavior. Culvert valve and intake/
base width. However, bearing capacity at the outer
discharge monoliths can be considered three-
edges of the structure is a concern. Stability with
dimensional monoliths due to their geometry but
respect to resultant location is defined in EM-1110-2-
generally two-dimensional approximations of these
2200 and EM 1110-2-2502. More information on
monoliths can be made which adequately capture
resultant location calculations is found in para-
their behavior for design purposes. Seismic analyses
graph 6-3. When performing resultant calculations it
and nonlinear, incremental structural analyses of the
is important that unfactored loads be used. The resul-
culvert valve and intake/discharge monoliths should
tant should fall within the middle third of the struc-
be three-dimensional analyses since the geometry of
ture under usual loading conditions.
the structure has a much larger impact for these
analyses than for static structural analyses. Chamber
3-3. Strength. All components of a lock monolith
monoliths behave strictly as two-dimensional mono-
liths unless a loading in the longitudinal direction is
must be able to resist all load conditions, including
placed on the monolith.
the reinforced concrete framing members, structural
and miscellaneous steel, foundation piling, and foun-
dation material.
3. Design Criteria
a. Reinforced concrete. Detailed design guid-
3-1. General. The design criteria for navigation
ance for reinforced concrete sections is covered in
locks must be established during the feasibility phase
EM 1110-2-2104.
of the design process. Criteria should cover stability,
strength, serviceability, and foundation requirements.
b. Steel structures. Design of structural steel,
There are three categories of loadings defined in
embedded metal, and miscellaneous steel should be
other guidance. These categories include usual,
based on EM 1110-2-2105. Design of major lock
unusual, and extreme load conditions as described in
appurtenances such as miter gates, tainter gate valves,
paragraph 5-2. The separation of load conditions into
and associated machinery is covered under various
these categories implys the nature, frequency, and
other guidance publications including EM 1110-2-
consequence of the loading and also dictates the
2703 and EM 1110-2-1610.
required factors of safety. The decrease in factor of
c. Foundation piling. Detailed design guidance
safety allowed in all three categories of loading main-
for pile foundations is contained in EM 1110-2-2906.
tains limits that yield a linear elastic response of the
Further discussion is found in paragraph 6 below.
structural elements. In some situations, however,
A-5
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