机械翻译Static and Dynamic Stress Analysis(静态和动态应力分析)

2021年1月20日发(作者：tender是什么意思)










































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Chapter 5
Static and Dynamic Stress Analysis
第五章

静态和动态应力分析

5-1. Stress Analysis
5-1.
应力分析

a. General.
(1) A stress analysis of gravity dams is performed to determine the magnitude and distribution of
stresses
throughout
the
structure
for
static
and
dynamic
load
conditions
and
to
investigate
the
structural adequacy of the substructance and foundation. Load conditions usually investigated are
outlined in Chapter 4.
(2)
Gravity
dam
stresses
are
analyzed
by
either
approximate
simplified
methods
or
the
finite
element
method depending on the refinement required for the particular level of design and the
type and configuration of the dam. For preliminary designs, simplified methods using cantilever
beam
models
for
two-dimensional
analysis
or
the
trial
load
twist
method
for
three-dimensional
analysis
are
appropriate
as
described
in
the
US
Bureau
of
Reclamation
(USBR),
“Design
of
Gravity
Dams”
(1976).The
finite
element
method
is
ordinarily
used
for
the
feature
and
final
design stages if a more exact stress investigation is required.
a.
普通方法

(1)
重力坝的应力分析是用以确定在静态和动态荷 载作用下结构的应力分布和大小情况以及
验证下部和基础的结构强度，荷载条件通常在第四章作了概述。

(2)
重力坝的应力分析通过基于满足坝体类型、构造和设计精度要求的近似的简化 方法或有
限单元法。初步设计时，根据美国垦务局（
USBR
）颁布的“重力坝设计规 范（
1976
）
”
，可
以使用二维的悬臂梁模型或者三维的模型试验 的简化方法。
有限单元法通常用于对应力精度
要求更高的详细和最终设计阶段。

b. Finite element analysis.
(1) Finite element models are used for linear elastic static and dynamic analyses and for nonlinear
analyses
that
account
for
interaction
of
the
dam
and

finite
element
method
provides the capability of modeling complex geometries and wide variations in material properties.
The stresses at corners, around openings, and in tension zones can be approximated with a finite
element
model.
It
can
model
concrete
thermal
behavior
and
couple
thermal
stresses
with
other

important
advantage
of
this
method
is
that
complicated
foundations
involving
various
materials, weak joints on seams, and fracturing can be readily modeled. Special purpose computer
programs
designed
specifically
for
analysis
of
concrete
gravity
dams
are
CG-DAMS
(Anatech
1993),
which
performs
static,
dynamic,
and
nonlinear
analysis
and
includes
a
smeared
crack
model,
and
MERLIN
(Saouma
1994),
which
includes
a
discrete
cracking
fracture
mechanics
model.
b.
有限元分析

(1)

有限元模型用于线性弹性的静态 和动态分析以及坝体与基础相互影响的非线性分析。
有
限元方法具有模拟具有复杂几何形状和不 同材料性能的能力。
角落处，
开口处和有张力处的
应力可以用有限元模型来近似。它可 以模拟混凝土的热行为和由其他荷载引起的温度应力。
此方法的重要优点是对于涉及各种材料的复杂的基 础，接缝薄弱处和断裂面能很容易模拟。
专门设计用来对混泥土重力坝分析的专用计算机程序是
CG-DAMS
（
Anatech1993
年）
，它
执行静态，动态 和非线性分析，并包括一个弥散裂缝模型，梅兰（萨乌马
1994
年）
，其中
包括离散裂缝断裂力学模型。












































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(2) Two-dimensional, finite element analysis is generally
appropriate for concrete gravity dams.
The
designer
should
be
aware
that
actual
structure
response
is
three- dimensional
and
should
review
the
analytical
and
realistic
results
to
assure
that
the
two- dimension
approximation
is
acceptable
and
realistic.
For
long
conventional
concrete
dams
with
transverse
contraction
joints
and
without
keyed
joints,
a
two- dimensional
analysis
should
be
reasonably
correct.
Structures
located in narrow valleys between steep abutments and dams with varying rock moduli which vary
across the valley are conditions that necessitate three-dimensional modeling.
(2)

二维的有限元分析一般用于混凝土重力坝。但是设计者应该知道，实际的结构 响应是三
维的，
应审查理论值和真实值以保证这二维近似方法是合理和有效的。
对于较 长的并设有横
缝的常规混凝土大坝，
二维的分析应是相当正确的。
当结构位于陡峭的桥 台之间的狭窄山谷
和大坝在各处有不同的岩石模量时则需要使用三维建模。

(3) The special purpose programs Earthquake Analysis of Gravity Dams including Hydrodynamic
Interaction(EADHI)(Chakrabarti and Chopra 1973) and Earthquake Response of Concrete Gravity
Dams
Including
Hydrodynamic
and
Foundation
Interaction
Effects
(EAGD84)(Chopra,
Chakrabarti,
and
Gupta
1980)
are
available
for
modeling
the
dynamic
response
of
linear
two-dimensional structures. Both programs use acceleration time records for dynamic input. The
program
SDOFDAM
is
a
two-dimensional
finite
element
model
(Cole
and
Cheek
1986)
that
computes
the
hydrodynamic
loading
using
Chopra’s

simplified

finite
element
programs
such
as
GTSTRUDL,
SAP,
ANSYS,
ADINA,
and
ABAQUS
provide
general
capabilities for modeling static and dynamic responses.
(3)
一些专用的程序如重力坝地震分析及水动力作用
（
EADHI
）
（查克拉巴蒂 和乔普拉
1973
）
、
流体作用下的混凝土重力坝的地震响应分析和地基交互 影响（
EAGD84
）
（乔普拉，查克拉
巴蒂，和
Gupta198 0
年）可用于模拟线性二维结构的动力响应。这两个程序都对与动态输
入使用加速度时间记录。
SDOFDAM
程序是用乔普拉简化程序计算水动力荷载的一个二维
有限元模型。一些有限元程序如
GTSTRUDL, SAP, ANSYS, ADINA,
和

ABAQUS
提供了模
拟静态和动态响应的能力。

5-2. Dynamic Analysis
The
structural
analysis
for
earthquake
loadings
consists
of
two
parts:
an
approximate
resultant
location and sliding stability analysis using an appropriate seismic coefficient(see Chapter 4) and a
dynamic internal stress analysis using site- dependent earthquake ground motions if the following
conditions exist:
5-2
动态分析

地震荷载的结构分析包括两部分：一个使用适当的抗震系数 （见第
4
章）的位移和抗滑稳
定的近似结果和一个满足下列条件的基于地震动的动态内 应力分析：


a. The dam is 100 feet or more in height and the peak ground acceleration (PGA) at the site is
greater than 0.2 g for the maximum credible earthquake.
a.

大坝高
100
英尺以上以及一点对于地震幅度的峰值加速度（
PGA
）大于
0.2 g
。

b. The dam is less than 100 feet high and the PGA at the site is greater than 0.4 g for the maximum
credible earthquake.
b.

大坝高度低于
100
英尺且一点相对于地震幅度的峰值加速度
PGA
大于
0.4g
。

c.
There
are
gated
spillway
monoliths,
wide
roadways,
intake
structures,
or
other
monoliths
of
unusual shape or geometry.
c.

有门控泄洪坝段，宽的通道，进水口，或其他有不寻常的几何形状的坝段。

d.
The
dam
is
in
a
weakened
condition
because
of
accident,
aging,
or
deterioration.
The











































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requirements
for
a
dynamic
stress
analysis
in
this
case
will
be
decided
on
a
project-by-project
basis in consultant and approved by CECW-ED. < br>d.
大坝由于意外情况，老化，或恶化而处于性能衰减的状况。在这种情况下的动态应力分析的要求将决定于专家的且被
CECW-ED
认可的项目标准。

5-3. Dynamic Analysis Process
The procedure for performing a dynamic analysis include the following:
a. Review the geology, seismology, and contemporary tectonic setting.
b. Determine the earthquake sources.
c.
Select
the
candidate
maximum
credible
and
operating
basis
earthquake
magnitudes
and
locations.
d. Select the attenuation relationships for the candidate earthquakes.
e.
Select
the
controlling
maximum
credible
and
operating
basis
earthquakes
from
the
candidate
earthquakes based on the most severe ground motions at the site.
f. Select the design response spectra for the controlling earthquakes.
g. Select the appropriate acceleration-time records that
are compatible with the design response
spectra if acceleration-time history analyses are needed.
h. Select the dynamic material properties for the concrete and foundation.
i. Select the dynamic methods of analysis to be used.
j. Perform the dynamic analysis.
k. Evaluate the stresses from the dynamic analysis.
5-3
动态分析过程

执行动态分析的过程包括以下内容：

a.
调查其地质学，地震学及当代构造环境。

b.
确定地震的来源。

c.
确定设计值、地震震级和位置。

d.
确定地震的衰减关系。

e.
确定基于最严重的地面运动的设计地震的最大可控值和操作标准。

f.
确定用于控制地震的设计反应谱。

g.
如果需要进行加速度< br>-
时间时程分析时，确定合适的满足设计反应谱的加速度
-
时间记录。

h.
确定混凝土和基础的动态材料属性。

i.
确定用来进行动力学分析的方法。

j.
进行动力学分析。

k.
通过动力学分析求得应力值。

5-4. Interdisciplinary Coordination
A
dynamic
analysis
requires
a
team
of
engineering
geologists,
seismologists,
and
structural
engineers. They must work together in an integrated approach so that elements of conservatism are
not
unduly
compounded.
An
example
of undue
conservatism
includes
using
a
rare
event
as
the
MCE, upper bound values for the PGA, upper bound values for the design response spectra, and
conservative
criteria
for
determining
the
earthquake
resistance
of
the
structure.
The
steps
in
performing a dynamic analysis should be fully coordinated to develop a reasonably conservative
design with respect to the associated risks. The structural engineers responsible for the dynamic
structural
analysis
should
be
actively
involved
in
the
process
of
characterizing
the
earthquake
ground motions (see paragraph 5-6) in the form required for the methods of dynamic analysis to
be used.











































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5-4.
各学科之间的相互配合

动 态分析需要工程地质学家，
地震学家和结构工程师的合作。
他们必须相互协调的工作在一
起以便少部分的保守主义不会过度的复杂化。
过分保守的例子包括使用如
MCE
的一 个罕见
事件，上界的
PGA
值，上界值的设计反应谱，以及确定结构抗震的保守标准。 在进行动态
分析的步骤应充分配合以得出在相关风险下相当保守的设计。
负责结构动力分析的结 构工程
师应积极参与到所用的动态分析方法对地震地面运动特征
（见第
5-6
）
的形式要求的过程中。

5-5. Performance Criteria for Response to Site-Dependent Earthquakes
a.
Maximum
credible
earthquake.
Gravity
dams
should
be
capable
of
surviving
the
controlling
MCE
without
a
catastrophic
failure
that
would
result
in
loss
of
life
or
significant
damage
to
property. Inelastic behavior with associated damage is permissible under the MCE.
b. Operating basis earthquake. Gravity dams should be capable of resisting the controlling OBE
within the elastic range, remain operational, and not require extensive repairs.
5-5.
某点的地震响应性能判别标准

a.
可 信地震最大值。重力坝应具有继续控制
MCE
的能力而不会造成人员死亡或重大财产损
失等灾难性后果。

b.
地震控制标准。重力坝应具有在弹性范围内抵抗控制
OBE
，保持运行且不用大修的能力。

5-6. Geological and Seismological Investigation
A
geological
and
seismological
investigation
of
all
damsites
is
required
for
projects
located
in
seismic
zones
2
through
4.
The
objectives
of
the
investigation
are
to
establish
controlling
maximum
and
credible
operating
basis
earthquakes
and
the
corresponding
ground
motions
for
each
and
to
assess
the
possibility
of
earthquake-induced
foundation
dislocation
at
the
site.
Selecting the controlling earthquakes is discussed below. Additional information is also available
in TM 5-809-10-1.
5-6.

地质和地震调查

关于所有水 库所在地地质和地震调查需要在地震带
2
到
4
个调查项目。调查的目的是为了
对每个点建立控制最大值和可信的地震控制标准和相应的地震地面运动，
并评估在当地由地震引起的地基错位的可能性。
下面讨论了确定控制地震。
其他信息也可在
TM5- 809-10-1
找
到。

5-7. Selecting the Controlling Earthquakes
a. Maximum credible earthquake. The first step for selecting the controlling MCE is to specify the
magnitude and/or modified Mercalli (MM) intensity of the MCE for each seismotectonic structure
or
source
area
within
the
region
examined
around
the
site.
The
second
step
is
to
select
the
controlling
MCE
based
on
the
most
severe
vibratory
ground
motion
within
the
predominant
frequency
range
of
the
dam
and
determine
the
foundation
dislocation,
if
any,
capable
of
being
produced at the site
by the candidate MCE’s. If more than one can
didate MCE produce the largest
ground motions in different frequency bands significant to the response of the dam,each should be
considered a controlling MCE.
5-7.
确定控制地震

a.
可信地震最大值。
用于确定 控制
MCE
的第一步是为在工地附近的检查区域内的
每个地震构造结构或水源区指定< br>MCE
的大小和
/
或修改其麦加利（毫米）强度。
第二步是选择建立在 大坝内主要频率范围内最严重的地震动的控制
MCE
，
并确定基础错位，
即此 处
MCE
的延展能力。如果有不止一个预选的
MCE
产生对大坝响应重大的在 不同频段
的最大地面运动，则每个都应看作一个控制
MCE.

b. Operating basis earthquake.











































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(1) The selection of the OBE is based upon the desired level of protection for the
project from
earthquake-induced damage and loss of service project project life of new dams is usually
taken as 100 years. The probability of exceedance of the OBE during the project life should be no
greater than 50 percent unless the cost savings in designing for a less severe earthquake outweighs
the risk of incurring the cost of repairs and loss of service because of a more severe earthquake.
b.
地震设防标准。

(1) OBE
的确定是建立在工程在遭受地 震破坏及超过使用年限时对工程期望得到的保护水平
的基础之上的。新建的大坝的工程使用年限一般取为
100
年。在使用期限内的
OBE
的超越
概率应不大于
50 %
，除非在设计时冒花钱在修理上而降低防震要求以及由于更多的地震而
丧失使用功能的风险节 约成本。

(2)
The
probabilistic
analysis
for
the
OBE
involves
developing
a
magnitude
frequency
or
epicentral
intensity
frequency
(recurrence)
relationship
of
each
seismic
source;
projecting
the
recurrence information from
regional
and
past data
into
forecasts
concerning
future
occurrence;
attenuating the severity parameter, usually either PGA of MM intensity, to the site; determining
the
controlling
recurrence
relationship
for
the
site;
and
finally,selecting
the
design
level
of
earthquake based upon the probability of exceedance and the project life.
(2)
对< br>OBE
的概率分析涉及到对每个震源研究其震级频率与震中频率（复发）之间的关系；
通 过对当地过去地震信息来预测将来的情况；
当地的某些参数，通常是
MM
强度的
PGA
的
衰减程度；
确定此处的控制复发的关系；
最后，
依据超越 频率及使用寿命确定抗震设防水平。

5-8. Characterizing Ground Motions
a. General. After specifying the location and magnitude (or epicentral intensity) of each candidate
earthquake
and
an
appropriate
regional
attenuation
relationship,
the
characteristics
of
vibratory
ground
motion
expected
at
the
site
can
be
determined.
Vibratory
ground
motions
have
been
described in a variety of ways, such as peak ground motion parameters, acceleration- time records
(accelerograms), or response spectra (Hayes 1980, and Krinitzsky and Marcuson 1983). For the
analysis and design of concrete dams, the controlling characterization of vibratory ground motion
should be a site- dependent design response spectra..
5-8.

表征地震动

a.

一般地
。
当指定了位置以及每 个预设地震的震级
（或震中强度）
且一个适当区域的衰减关
系，
则此处地面运 动的震动特征即可确定。
地震运动已经用很多方式进行了描述，
如地面运
动参数的峰值 ，加速度
-
时间记录（加速度）
，或
反应谱（海斯
1980
年，
Krinitzsky
和马库
森
1983
）
。对于混凝 土坝的分析和设计，对地震动的控制特征应基于此地的设计反应谱。

b. Site- specific design response spectra.
(1) Wherever possible, site-specific design response spectra should be developed statistically from
response spectra of strong motion records of earthquakes that have similar source and propagation
path properties as the controlling earthquake(s) and are recorded on a foundation similar to that of
the dam. Important source properties include magnitude and, if possible, fault type and tectonic
environment.
Propagation
path
properties
include
distance,
depth,
and
attenuation.
As
many
accelerograms as possible that are recorded under comparable conditions and have a predominant
frequency similar to that selected for the design earthquake should be included in the development
of the design response spectra. Also, accelerograms should be selected that have been corrected
for
the
true
baseline
of
zero
acceleration,
for
errors
in
digitization,
and
for
other
irregularities
(Schiff and Bogdanoff 1967).
b.

特殊地点的设计反应谱