-
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
Chapter 1
、
Structural Mechanics
结构力学
1
、
1
Classification and Behavior of Structural Systems
and Elements
系统结构与元素的分类与作用
1
、
2 Determinate
and Indeterminate Structures
静定与超静定结构
1
、
3
Structural Dynamics
结构动力学
Chapter
2
、
Structural Material
土木工程材料
2
、
1 Materials
for Concrete and Mix Proportion
砼材料及配比
2
、
2 Properties
of Concrete
砼的性能
2
、
3 Steel
Materials
钢材料
2
、
4 Structural
Steel Shapes
型钢
Chapter 3
、
Structural Design concepts
结构设计
3
、
1 Load
conditions and Load Paths
负载条件与加载路径
3
、
2 Limit
State Design
极限状态设计
Chapter 4
、
Concrete Structure
钢筋混凝土结构
4
、
1 Flexural
Behavior of Reinforced Concrete Beam
钢筋混凝土梁的弯曲性能
4
、
2 Shear and
Diagonal Tension in Reinforced Concrete Beam
钢筋混凝土梁的剪切与斜拉
4
、
3
Bond , Anchorage, and Development
Length
连接
,
锚固
,
基本锚固长度
Chapter 1
、
Structural Mechanics
结构力学
1
、
1
、
Classification and
Behavior of Structural Systems and Elements
系统结构与元素的分类与作用
Common
rigid
elements
include
beams,
columns
or
struts,
arches,
flat
plates,
singly
curved
plates,
and shells having a
variety of different
curvatures
、
Flexible
elements include cables (straight and
draped) and membranes(planar, singly
curved, and doubly curved)
、
In addition, there are a number of
other types of structures that are
derived from these
elements(e
、
g, frames,
trsses, geodesic domes,
nets,
etc
、
)(figure
1
、
1)
常见的刚性元件包括梁
,
柱
,
支撑
,
圆拱
,
平板
,
单向板弯曲面
,
具
有不同的曲率的翘体。柔性元素包括电缆
(
直披
)
与膜结构
(
平面
,
单向板弯曲面
,
双曲面
)
。此外也有一些来自这些元素
(
如框架
,
桁架
,<
/p>
测量短程线
,
网格等
)
Frames
框架
The
frame
has
rigid
joints
that
are
made
between
vertical
and
horizontal
members
、
This
joint
rigidity
imparts
(
给予
)
a
measure
of
stability
against
lateral
forces
、
In
a
framed
system
both
beams
and
columns
are bent or
bowed(
弯如弓的
)as a consequence
of the action of the load on the
structure
、
框架的垂直
与水平直接有刚性连接
,
这样的节点给予了一定程度上的稳定性
抵抗侧向作用力。在一个框架的系统
张
,
梁与柱的弯曲或弓形弯如弓的形状都就是结构上负载的作用效果。
Trusses
桁架
Trusses
are
structural
members
made
by
assembling
short,
straight
members
into
triangulated
patterns
、
The
resultant
(
组合的
,
合成的
)structure
is
rigid
as
a
result
of
the
exact
(
精确的
)
way
the
individual
line
elements
are
positioned
relative
to
one
another
、
Some
patterns
(e
、
g
、
a
pattern
of
squares
rather
than triangles) do not necessarily
yield a structure that is rigid (unless joints are
treated in the
same way as in framed
structures)
、
A truss
composed of discrete elements is bent in an
overall way
under
the
action
of
an
applied
transverse
loading
in
much
the
same
way
that
a
beam
is
bent
、
Individual
truss members, however, are not subject
to bending but are only either compressed or
pulled upon
、
桁架结
构构件就是通过短直杆组装成三角形的图案。
组合的结果的精确方式相对于彼此的位置的
各行元素的结构
就是刚性的。
不一定会产生某些刚性的模型
(
例如
,
一个模型
的平方不一定就是三角形图案
)(
除非在框架结构中相
同的处理
)
。由分立元件组成的桁架在大致相同
的方式
,
弯曲梁所施加的横向载荷的作用下
,
在一个整体方式的弯
曲。个人桁架构件
< br>,
不能弯曲只能压缩或拉后。
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
Arches
拱门
An
arch
is
a
curved,
line-
forming
structural
member
that
spans
between
two
points
、
The
exact
shape
of
the
curve
and
the
nature
of
the
loading
are
critical
determinants
as
to
whether
the
resultant
assembly
is
stable
、
When shapes are
formed by simply stacking rigid block elements,
the resultant structure
is functional
and stable only when the action of the load is to
induce in-plane forces that cause the
structure to compress
uniformly
、
Structures
of this type
cannot
carry
loads that induce
elongations
or any pronounced type of
bowing in the member (the blocks simply pull apart
and failure occurs)
、
The
strength
of
a
block
structure
is
due
exclusively
to
the
positioning
of
individual
elements,
since
blocks are typically either simply
rested one on another or mortared
together
、
The positioning
is,
in
turn,
dependent
on
the
exact
type
of
loading
involved
、
The
resultant
structure
is
thus
rigid
only
under very particular
circumstances
、
圆拱
一个拱形的弯曲线形成的结构部
件
,
两点之间的跨越。
曲线的精确性质
与性质就是所得到的组件就是否
就是稳定的关键决定因素。当通过简单地堆叠刚性块体元
件的形状形成的结构就是功能性的与稳定的
,
又有当负
载的作用就是诱导面内的力量时才导致结构的均匀压缩。
这种类型的结构
不能进行负载诱导伸长或任何明显的拉
伸
(
只需拉开块发生故障
)
。嵌段结构的强度就是由于单个元素
导致的
,
由于块通常就是在躺在另一个上或砂浆砌
在一起。只有在非常特殊的情况下
,
所得到的的结构
才就是刚性的。
The
rigid
arch
is
frequently
used
in
modern
building
、
It
is
curved
similarly
to
block
arches
but
is
made
of
one
continuous
piece
of
deformed
rigid
material
、
If
rigid
arches
are
properly
shaped,
they
can carry a load to
supports while being subject only to axial
compression, and no bending
occurs
、
The rigid
arch is better able to carry variations in the
design loading
than is its
block counterpart
made
of
individual
pieces
、
Many
types
of
rigid
arches
exist
and
are
often
characterized
by
their
support
conditions (fixed, two-hinged, three-
hinged)
、
现代建筑中常用的
刚性拱
,
同样就是弯曲的阻止拱
,
但它就是由一块连续变形的刚性材料制成的。
如果制成刚
性拱的形状
,
它们可以承受的负载支座仅受轴向压
缩的同时并没有发生弯曲。刚性拱就是能够更好地进行变化的
块对应的单件制成的。存在
许多类型的刚性拱的特点常常就是它们的支持条件
(
固定
,
双绞链、三铰链
)
Walls and
Plates
墙板
Walls
and flat plates are rigid surface-forming
structures
、
A load-bearing
wall can typically
carry both vertical
loads and lateral loads (wind, earthquake) along
its length
、
Resistance to
out-of-plane
forces
in
block
walls
is
marginal
、
A
flat
plate
is
typically
used
horizontally
and
carries
loads
by
bending
to
its
supports
、
Plate
structures
are
normally
made
of
reinforced
concrete
or
steel
、
墙板
墙壁与平板表面形成的结构就是
刚性的。
承重墙通常可以进行沿其长度的垂直荷载与侧向荷载
(
风。
地
震
)<
/p>
。砌块墙的平面的抵抗力就是微不足道的。通常用于平板进行水平与通过弯曲其支持负载。
板结构通常就是
由钢筋混凝土或刚组成的。
Horizontal
plates
can
also
be
made
by
assembling
patterns
of
short,
rigid
line
elements
、
Three-dimensional triangulation schemes
are used to impart stiffness to the resultant
assembly
、
水平板也可以通
过组装短
,
刚性线的模式。三维三角形测量设计就是用来赋予所
得到的组件的刚度的。
Long, narrow
rigid plates can
also be joined along
their long edges
and
used to
span
horizontally
in
beam-like
fashion
、
These
structures,
called
folded
plates,
have
the
potential
for
spanning
fairly
large distances
、
长
,
狭窄的刚性板也可以加入与使用到
时尚的水平跨越梁中。这些结构
,
被称为折叠的板
,
有可能跨越相当大
的距离。
Cylindrical Shells and Vaults
柱形壳与拱顶
Cylindrical barrel shells and vaults
are examples of singly curved-plate
structure
、
A barrel
shell spans longitudinally such that
the curve is perpendicular to the direction of the
span
、
When
fairly
long, a barrel shell behaves much like a beam with
a curved cross section
、
Barrel shells are
invariably made of
rigid materials
(e
、
g
、
,
reinforced concrete or
steel)
、
A vault, by
contrast, is
a
singly
curved
structure
that
spans
transversely
、
A
vault
can
be
conceived
of
as
basically
a
continuous
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典
翻译
arch
、
柱形壳与拱顶
圆柱型的筒与拱顶都就
是单独的弧形板式结构的例子。一个镜筒外壳跨越纵向曲线垂直的方
向的弧度。
当足够长的时候
,
每筒外壳采用的弧形截面梁很
像。
筒
,
炮弹等都提出了硬质材料
(
如钢筋混凝土或钢
)
。
相反的
,
储藏库就是一个单独的
弧形结构
,
横向跨越。储藏库可以设想基本就是就是一个连续的
拱。
Spherical Shells and
Domes
球壳与圆顶
A
wide
variety
of
doubly
curved
surface
structures
are
in
use
、
These
include
structures
that
are
portions
of
spheres
and
those
that
form
warped
surface
(e
、
g
,
the
hyperbolic
paraboloid
)
、
The
number
of shapes possible is
actually boundless
、
Probably the most common doubly curved structures
is the
spherical
shell
、
It
is
convenient
to
think
of
this
structure
as
a
rotated
arch
、
This
analogy,
however,
is actually misleading with respect to
how the structure actually carries loads because
of the fact
that
loadings
include
circumferential
forces in
spherical
shells
which
do
not
exist
in
arches
、
Domed
structures
can
be
made
of
stacked
blocks
or
a
continuous
rigid
material
(reinforced
concrete)
、
Shells
and
domes
are
very
efficient
structures
capable
of
spanning
large
distances
using
a
minimum
of
material
、
球形壳
各种各样的双曲面结构都在使
用中
,
这些包括球部与它所形成的扭曲的表面的结构
(
例如
,
双曲抛物
线
)
。
一些可能的形
状实际上就是无限的。
也许最常见的双曲面结构就是球壳。
它认
为这种结构的旋转拱很方便。
但就是
,
这个比喻实际上就是误导了结构就是如何进行负载的。
因为
,<
/p>
载荷包括切线力在球壳中不存在拱门。
圆顶
结构
,
可以由层叠块或连续的刚性材料
(
钢筋混凝土
)
组成。
壳顶结构就是非常有效的
,
它能够用最少的材料覆盖
很
大的距离。
Cables(
索
)
Cables are flexible structural
elements
、
The shape they
assume (take on )under a loading depends on
the nature and magnitude of the
load
、
When a cable is simple
pulled on at either end, it assumes a
straight shape
、
This type of cable is often called a tie-
rod
、
When a cable is used to
span between
two points and carry an
external point load or series of point loads, it
deforms into a shape made
up of a
series of straight-line
segments
、
When a continuous
load (distributed load,)is carried, the
cable
deforms
into
a
continuously
curving
shape
、
The
self
–
weight
of
the
cable
itself
produces
such
a catenary curve
Suspension cables can be used to span extremely
large distances
索
索就是可弯曲的结构元件。
它们呈现加载的形状取决于负载的性质与严重程度。
当很简单地拉索的任一端时
,
它假定了直板造
型。
这种类型的索通常被称为转向横拉杆。
当索用于跨越两个点
之间并进行外部负载或一系列的
点荷载
,
变形的形状由一系列的直线段。
当进行连续负载
(
分布荷载
),
索变形成了连续弯曲的形状。
索本身的自重
产生这样的悬链线
,
吊索可用于跨越非常大的距离。
Membranes, Tents, and Nets
膜、
帐篷、网
A
membrane
is
a
thin,
flexible
sheet
、
A
common
tent
is
made
of
membranes
surfaces
、
Both
simple
and
complex forms can be created using
membranes
、
For surfaces of
double curvature, such as a spherical
surface, however, the actual surface
would have to be made as an assembly of much
smaller segments,
since most membranes
are typically available only in flat
sheets
、
A further
implication of using a
flexible
membrane to create the surface is that it either
has to be suspended with the convex side
pointing downward or, if used with the
convex side pointing upward, supplemented by some
mechanism
to its
shape
、
Pneumatic, or air-
inflated, structures
、
The
shape of the membrane is maintained by
the
internal
air
pressure
inside
the
structure
、
Another
mechanism
is
to
apply
external
jacking
forces
that
stretch
the
membrane
into
the
desired
shape
、
Various
stressed-skin
structures
are
of
this
general
type
、
The need to
pretension the skin, however, imposes various
limitations on the shape that can
be
formed
、
Spherical
surfaces,
for
example,
are
very
difficult
to
pretension
by
external
jacking
forces,
while others, such
as the hyperbolic paraboloid, can be handled with
comparative ease
、
膜、
帐篷、
网
就
是一个薄的膜
,
柔性板
,
一个常见的帐篷就是由膜表面构成的。
既简单又复杂的形式可以创建使
用膜。
对于双曲率
,
如球面的表面。
但就是实际的表面将要作为一个组件的更小的段
,
因为大多数膜通常仅适用于
平板。
用
一柔性膜片创建表面的再一个含义就是
,
它要么必须暂停与凸侧
朝向下方
,
或者
,
如果使用凸侧朝上
,
通过
一些机制
来补充其形状。
充气式膜结构的膜形状就是由内部的结构的内部气压。
< br>另一种机制就是应用外部抬升力
,
《土木工程专业英语》
陈瑛
_
邵永波主编
_
< br>全文经典翻译
拉伸膜成所需的形状。强调皮肤的各种结
构的这种通用类型
,
然而
,
需要预拉伸皮肤施加各种条件的限制
,
可以形
成的形状。球的表面
,
就是非常困难的外部
顶力
,
但就是其她的
,
如双曲抛物面可以比较容易处理。
Nets are
very analogous to membrane
skins
、
By allowing the mesh
opening to vary as needed, a wide
variety
of
surface
shapes
can
be
formed
、
An
advantage
of
using
crossed
cables
is
that
the
positioning
of the cables mitigates fluttering due
to wind suctions and
pressures
、
In addition,
tension forces
are typically induced
into the cables by jacking devices, so that the
whole surface is turned into
a type of
stretched skin
、
This also
gives the roof stability and resistance to
flutter
、
网就是非常类似的
膜皮
,
通过使网眼根据需要进行变化
,
各种各样的表面形状可以形成。
使用交叉索的一个优点就
是
,
使索的定位减轻由于风的吸力与压力产生
的飘动。此外
,
张力通常诱导索顶装置
,
使整个表面变成一种类型的
伸展。这也给了顶板稳定性与抗颤
性。
1
、
2
2
、
Basic Issues in the
Analysis and Design of Structures
结构分析与设计中的基本问题
1
Fundamental Structural
Phenomena1
、
基本结构现象
Structure
components
could
break
apart
or
deform
badly
、
The
forces
causing
overturning
or
collapse
come
from
the
specific
environmental
(e
、
g
、
,
wind,
earthquakes,
occupancies
)or
from
the
self-
weight
of the form
itself
、
These same applied
loadings produce internal force in a structure
that stress
the material used and may
cause it to fail or deform
、
There are several fundamental ways in which
failure can
occur
、
结构组件可以破坏或严
重变形
,
由力的作用造成的倾覆或来自特定的环境
(
例如
,
风
,
地震
,
占用
)
再或者就是
本身的自重的形式。
这些相同的应用负荷产生的内力在一个结构中使用的材料可能会导致其变形或失败。
有几个
基本的方法
,
其中可能会发生故
障。
A first set
of
concerns
deals
with
the overall stability of a
work
、
As
a whole
unit, a structure
might overturn,
slide, or twist about its base, particularly when
subjected to horizontally acting
wind
or
earthquake
forces
、
Sliding
under
its
own
weight
、
Overturning
or
twisting
need
not
be
caused
only by horizontally
acting forces
、
A work might
simply be out of balance under its own self-weight
and overturning
、
The use of wide, rigid foundations helps prevent
overturning, as does the use of
special
foundation elements such as piles capable of
carrying tension forces
、
第一组关注处理工作的整体稳定性。作为一个整体单元
,
结构可能会倾覆
,
滑移
,<
/p>
扭转。尤其就是当风或地震
的水平作用时
,
其自身重量下滑
,
翻倒或扭转不只就
是引起水平作用力。在自身的重量与倾覆的作用下
,
可能只就<
/p>
是失去了平衡。使用宽
,
刚性的基础
,
有助于防止倾覆
,
不使用例如能够携带张力桩的特殊要数。
A
second
set
of
concerns
deals
with
internal,
or
relational,
stability
、
If
the
parts
of
a
structure
are
not properly arranged in space or interconnected
appropriately, an entire
assembly(
组装
)can
collapse
internally
、
Collapses of
this type invariably involve large relative
movements within the
structure
itself
、
Assemblies
may
be
internally
stable
under
one
loading
condition
and
unstable
under
another
、
Horizontally
acting
wind
or
earthquake
forces,
in
particular,
cause
collapses
of
this
kind
、
There
are
several
basic
mechanisms-walls,
frame
action, cross
bracing
–
for
making
an
assembly
internally
stable
、
第二组关于处理内部
关系稳定。
如果有部分的结构空间组合不合理
,
或真个组装不合理
,
可以适当地相互连接
,
内部折叠。
这种类型导致的坍塌总就是涉及大型结
构本身的相对运动。
组件可能就是一个装载条件下内部稳定与
不
稳定的根据项。
水平因素风或地震尤其会使其坍塌。
有几个基本
的机制墙壁
,
框架动作
,
交叉支撑组件的内部稳
定。
A third set of concerns deals with the
strength and stiffness of constituent
elements
、
There are
many
structure
issues
that
revolve
around
the
strength
of
component
parts
of
a
structure
、
These
failures,
which
may
or
may
not
lead
to
total
collapse,
may
be
caused
by
excessive
tension,
compression,
bending,
shear, torsional,
bearing forces, or deformations that are developed
internally in the structure as
a
consequence of the applied
loadings
、
Associated with
each force state are internal stresses that
actually
exist
within
the
fabric
of
the
material
itself
、
By
carefully
designing
components
in
response
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
to the force
state
present,
the actual stresses
developed in the
components
can be controlled to safe
levels
、
第三组的关注处理的强度与刚度的结构元素。
很多结构围绕一个结构组成部分的强度
问题。
这些故障可能会
导致全面崩溃
,
可能就是由于过度紧张
,
压缩
,
弯曲
,
剪切
,
扭转
,
轴承
,
或变形
,
在结构内部
开发的应用负荷的后果。
每个受力状态
,
实际上存在于物质材料本身的内应力。
通过仔细地设计组件的受力状态
,
开发组件的实际应力可以
被控制到安全水平。
2
、
Structural Stability
结构稳定性
A Fundamental consideration in
designing a structure is that of assuring its
stability under any
type
of
possible
loading
condition
、
All
structures
undergo
some
shape
changes
under
load
、
In
a
stable
structure
deformations
induced
by
the
action
of
the
load
tend
to
restore
the
structure
to
its
original
shape after the load has been
removed
、
In an unstable
structure, the deformations induced by a load
are
typically
massive
and
often
tend
to
continue
increasing
as
long
as
the
load
is
applied
、
An
unstable
structure does not
generate internal forces that tend to restore the
structure to its original
configuration
、
Unstable
structures
quite
often
collapse
completely
and
instantaneously
as
a
load
is
applied to them
、
It is the fundamental responsibility of the
structural designer to assure that a
proposed structure does indeed form a
stable configuration
、
设计结构的最基本需要考虑的问题
,
就是任何类型的
可能负载的条件下确保其稳定性。所有的结构进行一些
稳定结构的变形引起的负载的作用
下的形状变化
,
趋向于回访到初始形状的结构已经被删除。
在不稳定的结构中
,
由负载引起的变形通常
就是大规模的
,
并且常常施加载荷时
,
只要继续增加。
一个不稳定的结构不会产生内部的力
量
,
往往恢复到原来的配置结构。经常不稳定结构
完全折叠与瞬间作为负载被施加到它们身上。它的基本结构设
计师的责任
,
以确保建议的结构确实形成一个稳定的配置。
Stability
is
a
crucial
issue
in
the
design
of
structures
that
are
assemblies
of
discrete
elements
、
For example, the post-and-beam
structure illustrated in figure
1
、
2a is apparently
stable
、
Any
horizontal
force,
however,
tends
to
cause
deformations
of
the
type
indicated
in
figure
1
、
< br>2b
、
clearly,
the structure has no capacity to resist
horizontal load, nor does it have any mechanism
that tends
to restore it to its initial
shape after the horizontal load is
removed
、
The large changes
in angle
that occur between members
characterize an unstable structure that is
beginning to collapse
、
This
particular
structure
will
collapse
almost
instantaneously
under
load
、
Consequently,
this
particular
pattern of
members is referred to as a collapse
mechanism
、
稳定就是一个
至关重要的问题
,
在设计分立元件的组件结构。
例如
,
梁柱结构示意图
1
、
2a
所示显然就是稳定
< br>的。然而
,
在任何水平方向的力往往会造成在图
1
、
2b
的不同变形。
结构清楚
,
有没有能力抵抗水平荷载
,
也没有
任何机制
,
倾向于恢复到其初始形状
,
水平荷载后删除。
出现大的变化角度特征不稳定的结构开始崩溃。
这种特殊
的结构将在负载下瞬间崩溃。因此
,
这个特定的图案被称为
“崩溃机制”
There
are
really
only
a
few
fundamental
ways
of
converting
a
self-standing
structure
of
the
general
type
shown
in
figure
1
、
2a
fron
an
unstable
to
a
stable
configuration
、
These
are
illustarated
in
figure
1
、
2d
、
the
first
is
to
add
a
diagonal
member
to
the
structure
、
The
structure
cannot
now
undergo
the
parallelogram
indicated
in
figure
1,2b
without
a
dramatic
release
in
the
length
of
the
diagonal
member
(this would not occur
if the diagonal were adequately sized to take the
forces involved)
、
Another
method
used
to
assure
stability
is
through
shear
walls
、
These
are
rigid
planar
surface
elements
that
inherently resist shape
changes of the type
illustrated
、
A reinforced
concrete or masonry wall can
be
used
as
a
shear
wall
、
Either
a
full
or
a
partial
wall
can
be
used
(the
required
extent
of
a
partial
wall depends on the
magnitudes of the forces
involved)
、
A final method
used to achieve stability is
through
stopping
the
large
angular
changes
between
members
that
are
associated
with
collapse
by
assuring
that
the
nature
of
the
nature
of
the
connections
between
members
is
such
that
their
angular
relationship
remains a constant value under any
loading
、
This is done by
making a rigid joint between
members
、
This is
a very common form of joint
、
真的只有一项独立的通用型数字
1
、<
/p>
2a
不稳定的一个稳定的配置结构转换的一些基本方法。这些在图
1
、
2d
《土
木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
上。成为第一个就是增
加一个对角构件的结构。结构现在不能接受对角线的长度
(
如果
对角线有足够大的力量
,
这种情况不会发生
)
没有一个戏剧性的释放
b
图
1,2
所示的平行四边形。用来保证稳定性的另一种方法就是通过<
/p>
剪力墙。
这些平面的表面就是刚性的元素本质上所示类型的抗蚀剂
形状的变化。
可用于钢筋混凝土或砖石墙作为
剪力墙。
完整或部分的壁可用于
(
部分壁所需的程度上依
赖于所涉及的力的大小
)
。
用于实现稳
定的最后一种方法
就是通过停止大角度变化
,
< br>确保结构之间的连接的性质就就是这样原理的性质
,
它们
的角的关系仍然就是一个恒
定值。这就是通过成员之间的刚性连接
,
就是一个非常普遍的形式的联合。
There
are,
of
course,
variants
on
these
basic
methods
of
assuring
stability
、
Still
most
structures
composed
of
discrete
elements
rely
on
one
or
the
other
of
these
basic
approaches
for
stability
、
More
than
one
approach
can
be
used
in
a
structure
(e
、
g
、
a
structure
having
both
rigid
joints
and
a
diagonal),
but a measure of redundancy is
obviously involved
、
< br>当然
,
在这些基本的方法保证稳定的变体。仍然由分立元
件组成的结构依赖于一个或另一个稳定这两种基本
方法。在一个结构中
< br>,
可以使用一个以上的方法
(
例
如
,
具有两个刚性接头与对角线结构
)
,
但显然这涉及一定程度
的冗余。
1
、
2 Determinate
and Indeterminate Structures
静定与超静定结构
1
、
2Determinate
and Indeterminate
Structures
静定与超静定结构
1
、
2
、
1 Statically Determinate
Structures
超静定结构
Structures
are
said
to
be
statically
determinate
when
the
forces
and
reactions
produced
by
a
given
loading can be calculated using only
the equations of
equilibrium
、
The simply
supported beam shown
in Figure
1
、
3 is statically
determinate
、
We can solve
for the three unknown reactions using the
equations of equilibrium and then
calculate the internal forces such as bending
moment, shear force,
and axial force at
any given location along the length of the
beam
、
结构被称为静定时的力与反应的一个给定的荷载产生可以只使用平衡方程计算。
简支梁在图
1
、
3
所示就是静
定。
我们可以解决三未知的反应
,
利用平衡方程
,
然后计算等
内力弯矩
,
剪切力
,
< br>与在任何给定的位置沿梁的长度的
轴向力。
1
、
2
、
3
Force Method
力法
The force method (also called the flexibility
method) is used to calculate internal forces and
reactions in statically indeterminate
structures due to loads and imposed
deformations
、
力法<
/p>
(
又称弹性法
)
就是用来计算内力与反应静不定结构因荷载与施加变形。
在力法的步骤
The steps
in the force method
在力法的步骤
(1)Determine
the
degree
of
statical
indeterminacy
of
the
structure
、
Parameter
n
will
be
used
to
denote
the degree of
indeterminacy
、
(1
)
确定静不定结构的程度。参数
n
可以
用来表示不确定性的程度。
(2) Transform
the structure into a statically determinate system
by releasing a number of statical
constraints equal to the degree of
statical indeterminacy,n
、
This is accomplished by
releasing
external support conditions
creating
internal hinges
、
The system thus formed is called the
primary system
、
Number the
released constraints from 1 to
n
、
(2)
通过释放一些静态约束等于静不定度的结构转化为静定系统
,
这就是通过
释放外部支持条件
,<
/p>
创建内部铰链。由此形成的系统称为原发性系统。编号从
1
到
N
的释放的约束
(3)For a given released constraint j,
introduce an unknown redundant force Xj
corresponding to the
type and direction
of the released constraint
、
(3)
基本体系沿多余未知力方向的位移应与原结构位移相同
(4)Apply the given loading or imposed
deformation to the primary
system
、
Calculate
displacements
due
to
the
given
loading
at
each
of
the
released
constraints
in
the
primary
system
、
These
displacements
are called
Δ
1P ,
Δ
2P ,
Δ
nP
、
、
,
、
(4)
将给定的加载或主系统的附加变形。计算的位移由于在原系统在每个发布约束给定载荷。这些位移被称为
Δ
1P,2P
Δ
,<
/p>
Δ
NP
、
、
,
(5)For a given released constraint j, apply a unit
load Xj =1 to the primary
system
、
Calculate
displacements
due
to
Xj
=1
at
each
of
the
released
constraints
in
the
primary
system
、
These
displacements are
called
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
(5)
对于一个给定的发布约束
J,
申请单位负载
XJ =
1
到主系统。计算的位移由于
XJ = 1
在每个释放的约束在
主系统。这些位移被称为
,,
(6)Solve for redundant forces X1
through Xn by imposing the compatibility
conditions of the original
structure
、
These
conditions transform the primary system back to
the original structure by finding
the
combination of redundant forces that make
displacement at each of the released constraints
equal
to zero
、
The
conditions are expressed mathematically as follow
This
is
a
system
of
n
linear
equations
in
n
unknows,The
displacements
arw
all
know
、
The
unknow
forces
are
Xj
、
It
can
thus
be
seen
that
the
name
of
force
method
was
given
to
this
method
because
its
primary
computational task
is to calculate unknown forces,i
、
e
、
,the redundant forces
X1 through Xn
、
(6
)
解决多余力
X1
到
< br>XN
利用原结构的相容性条件。这些条件将原系统回到原来的结构的发现使位移在
每个发布
约束等于零冗余力量的结合。条件的数学表达如下
<
/p>
这就是一个
N
未知数的线性方程系统
,
位移
ARW
都知
道。未知的力量就是
XJ
。由此可以瞧出
,
力方法的名称分
配给该方法由于其计算的基本任务就是计算
未知的力量
,
即
,
多余的力
X1
到
Xn
。
(7)Calculate force S
at a given location in the structure using the
following combination
where
quantities Xj have been calculated from the n by n
system of equations given in Step6,S0
is the force due to the given load or
imposed deformation in the primary system,and X0
is the force
due
to
Xj
applied
to
the
primary
system
、
Force
S
can
be
bending
moment,shear,axial
force,or
reaction
、
(7)
计算力的结构中在某一位置使用下列组合
在大量
XJ
已经从
n
的
n
系统方程计算了六
,S0
力就是由于负载或施加的变形的主要系统
,<
/p>
与
x0
就是力由于
XJ
施
加到主系统。力的可弯曲
,<
/p>
剪切
,
轴向力
,
或反应。
1
、
2
、
4The classical
Displacement Method
经典的位移的方法
The force method is a method for
calculating the response of statically
indeterminate strures by
which
the
unknows
are
force
quantities(the
redundant
force
X
1,X2
、
、
、
,Xn)and
the
equations
used
to
solve
for
the
unknows
are
based
on
geometrical
conditions
(compatibility
conditions
at
the
location
of
each
redundant
force)
、
It is possible to
consider an analogous method for calculating the
response of
statically
indeterminate
structures
in
which
the
unknowns
are
displacement
quantities
and
the
equations
use to solve for the unknowns are based
on statical conditions (equilibrium
conditions)
、
力法就是
一种计算响应静不定结构的未知力量
(
多余力的
X1,X2
……
,xn)
与方
程来求解未知量就是基于几何条件
(
在每一个多余的力的位置的
相容性条件
)
。
可以考虑类似的方法计
算响应的静不定结构的未知位移量与方程求解
的未知数就是使用基于静态条件下
(
平衡条件
)
。
the method is referred to as
the classical displacement
method
、
It is helpful to
outline the major
elements of the
method
、
It is assumed that
the joints of the structure do not undergo
translational
displacement
、
该方法被称为传统的位移法。它有助于轮廓的方法的主要元素。它就是假定的结构节点不发生平
动位移。
(1)For a given
structure and loading,consider the joints to be
fully fixed against rotation
(1)
对于一个给定的结构与加载
,
考虑关节得到充分固定在
旋转
(2)Calculate the moments
in each member of the structure due to the given
loads,assuming full fixity
at
joints
、
These moments are
called fixed-end moments
、
(2)
计算结构的每一成员由于负载的时刻
,
假设固定节点。这些时刻被称为固定端弯矩。
(3)Calculate the moments iat the ends
of each member due to unit displacements of the
joints
、
(3)
计算时刻的
IAT
的每一个成员由于接头的两端单元
位移。
(4)Express the total
moment at each end of a given member as the sum of
the fixed-end moments and the
product
of
unknown joint
displacements
times
the
moments
produced
by unit
joint
displacements
calculated in Step
3
、
(4)
表示的总的时刻在一给定成员每一端为固定端的时刻与未知节点位移时间单元节点位移在步骤
3
中计算产生
的矩的乘积的总与。
(5) Generate an equation of moment
equilibrium at each joint
、
(5)
产生在各关节的力矩平衡方程。
(6) Solve the system of equations for
the unknown joint
displacements
、
(6)
求解未知节点位移方程组。
(7) Calculate the member end moments
using the expressions derived in Step 4 and the
values of joint
displacements
calculated in Step 6
、
(7)
使用在步骤
4
中得到
表达与节点位移在步骤
6
中计算值的构件端弯矩计算。
(8)Calculate all remaining
forces in the structure (shear forces and axial
forces)
、
《土木工程专业英
语》陈瑛
_
邵永波主编
_
全文经典翻译
(8)
计算
结构中的所有剩余的部队
(
剪力与轴力
)
。
Force
method
can
solve
all
statically
indeterminate
structures
、
computational
complexity
prohibitive
for structures
with more than three unknown
forces
、
力的方法可以解决所
有的静不定结构
,
计算的复杂性
,
高昂的结构与三多个未知的力量。
Classical displacement method allows a
solution based on a member-by-member procedure,
rather than
one that requires
consideration of the structure as a whole;
based on the pre-solution of standard
cases of intermediate
媒介物
load and displacement
reduce the number
of unknowns in a given
solution
、
传统的位移法允
许基于构件的构件程序的解决方案
,
而不就是一个需要考虑的结
构作为一个整体
;
基于中间媒介
物载荷
与位移的标准的情况下
,
预解在一个给定的溶液减少未知数的个
数
。
1<
/p>
、
2
、
5Mom
ent Distribution Method
力矩分配法
The
moment
distribution
method
is
used
for
statically
indeterminate
beams
and
frames
by
simple
hand
calculations
、
This
is
basically
an
iterative
(
迭代的
)
process
、
The
procedure
involves
artificially
restraining
temporarily all the joints against rotation and
writing down the fixed end moments for
all
the
members
、
The
joints
are
then
released
one
by
one
in
succession
连续、
At
each
released
joint
the unbalanced moments are distributed
to all the ends of the members meeting at that
joint
、
力矩分配法用于静不定
梁与框架通过简单的手工计算。
这基本上就是一个迭代过程
(<
/p>
迭代的
)
。
该过
程涉及人为
地抑制暂时所有接头与旋转的固定端的时刻写下所有的成员。接头然后释放一
个个相继连续。
在每个节点不平
衡弯
矩释放在联合分布于会员大会结束一切。
A certain
fraction of these distributed moments are carried
over to the far ends of
members
、
The
released joint is again restrained
temporarily before proceeding to the next
joint
、
The same set of
operations
are
carried
out
at
each
joint
till
all
the
joints
are
completed
、
This
completes
one
cycle
of
operations
、
The
process
is
repeated
a
number
of
times
or
cycles
till
the
values
obtained
are
within
the
desired accuracy
、
一定比例的这些分布的矩进行了构件的远端。
释放接头又得到了暂时的抑制后再进行下
一节。
一组相同的操作
在每个节点到所有节点进行完成。
这就完成了一个周期的操作。
这个过程就是重复的次数或周期直到得到
的值就
是在所需的精度。
Figure 1
、
5
indicates a basic problem of moment
distribution
、
The question
is,given a unit moment
applied to
jointA,what moments are produced in each of the
members
、
One way to proceed
is to solve
the problem for a unit
joint rotation andthen scale the resulting
solution for a unit
moment
、
For a
unit
rotation the moment in each member at joint A is
just its stiffness kI=(4EI/L)i
、
< br>The(1
、
2
、
3
公式
)
which
is
called
the
joint
stiffness
、
For
anapplied
unit
moment
this
solution
scales
so
that
the
moment in each meber at joint A is(1
、
2
、
4
公式
) this is called the
distribution factor of member i
at join
A
、
That is member
distribution factor=member stiffness/joint
stiffness
图
1
、
5
显示的弯矩分布的一个基本问题。
问题就是<
/p>
,
给定一个适用于节点及单元的时刻
,<
/p>
什么时刻都在每一成
员的产生。的方式来进行
,
以解决单位共同旋转而产生的解决方案规模单位的时刻的问题。对一个单位在每个
旋
转力矩会员在关节就是其刚度
ki
＝
(4ei
／
L)
——
(1
、
2
、
3
公式
),
称为关节僵硬。因为从单元转动这个解决方案
的尺度
,
每个成员在关节力矩
(1
、
< br>2
、
4
公式
)
这就就是所谓的分布因子的成员在加入我。这就是成员的分配系数
=
构件刚度
/
关节僵硬
The problem inFigure
1
、
6 can be
solved
、
First, the center
joint is fixed (the rotation is set to
zero ) which gives the so- called
fixed-end moment solution for beam on the right
and no response in
the beam on
the left
、
This
solution is valid
except that it
requires
an
external moment to be applied
to
the
center
joint
、
the
final
solution
is
constructed
by
releasing
or
balancing
the
center
joint
which
is equivalent to
applying a clockwsie moment of wl2/12 to this
joint
、
Using the idea of
distribution
and carry over,the
solution is completed in this
figure
、
Note that the sign
convention used implies
that
a
counter-clocwise
moment
on
the
end
of
a
member
is
positive
、
Care
must
then
be
exercised
in
drawing
the final moment
diagram which uses a different a different sign
covention
、
图
1
、
6
的问题就是可以解
决的。第一
,
中心节点就是固定的
(<
/p>
旋转设置为零
),
梁的右侧与左侧梁没有
反应了
,
所谓的固定端弯矩的解决方案。
该方案就是有效的
,
它除了需要应用于中心
< br>joint
、
the
最终解的外
部力矩就是通
过释放或平衡中心联合相当于应用
wl2
/
12
clockwsie
时刻本联合建造。使用分布式的思想与携带
,
解决的办法
就是在图中完成。注意
,
使
用的符号规定意味着在一个部件的端
clocwise
时刻计数
器就是积极的。然后
,
必须使
用不同的
符号绘制不同的最后一刻图执行公约。
1
、
3Structural
Dynamics
结构动力学
;
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
1
、
3
、
1Equation
s of Motion for Linear Single-Degree-of
–
Freedom
运动方程的线性单自由度
The
essential physical properties of a linearly
elastic structural system subjected to external
dynamic loading are its mass,stiffness
properties,and energy absorption capability or
damping
、
The
principle of dynamic analysis may be
illustrated by cinsidering a simple single-storey
structure as
shown
in
Figure1
、
7
、
The
structure
is
subjected
to
a
time-varying
force
f(t)
、
k
is
the
spring
cinstant
that relates the
lateral storey deflection x to the storey shear
force,and he dash pot relates the
damping force to the velocity by a
damping coefficient c
、
If the
mass,m,is assumed to concentrate at
the
beam,the structure becomes a single-degree-of
-freedom (SDOF)system
、
The
equation of motion of
the system may be
written as(1
、
3
、
1
公式
)
、
一个线性弹性结构体系进行了外部动力荷载的基本物理特性就是它的
质量
,
刚度
,
与能量吸收能力或阻尼。
动态分析的原理
,
可以通过一个简单的单层结构
,
考虑在
figure1
、
7
、
the
结构显示了受到时变力
F(t)
。
K
就是弹
簧常数
,
涉及横向偏转
X
层
的层高的剪切力
,
与她锅涉及阻尼力速度的阻尼系数
C
。如果质量
,m,
就是
假设集中在
梁
,
结构成为一个单自由度
(SDOF)
系统的运动方程可系统。被写为
< br>(1
、
3
、
1
公式
)
。
If
a
stucture
is
subjected
to
a
sinusoidal
motion
such
as
a
ground
acceleration
of
xg=fsinwft,it
will
oscillate
and
after
some
time
the
motion
of
the
structure
will
reach
a
steady
state,For
example,the
equation
of
motion
due
to
the
ground
acceleration(1
、
3
、
2
公式
)where
2sw=c/m
and
w2=k/m,w
is
the
resonate
natural frequency
of the system
、
如果一个结构进行正弦运动如
XG
=
fsinwft
地面加速度
,
它将振荡
,
经过一段时间的结构的运动会达到一
个
稳定的状态
,
例如
< br>,
由于地面加速度的运动方程
(1
、
3
、
2
公
式
)
在
2SW = C /
M
与
W2 = K
/M,W
就是共振系统的自
然频率。
The
solution
to
the
above
equation
consists
of
two
parts,the
general
solution
and
the
particular
solution,If the
system is damped,oscillation corresponding to the
general solution will decay with
time,After some time,the motion will
reach a steady state and the system will vibrate
at a constant
amplitude
and
frequency
、
This
motion,which
is
called
forced
vibration,is
described
by
the
particular
solution
expressed
as(1
、
3
、
< br>3
公式
)
、
Substituting
Equation
(1
、
3
、
3)int
o
Equation
(1
、
3
、
2),the
displacement
amplitude can
be shown to be (1
、
3
、
4
公式
)
、
上述方程的解由两部分组成
,<
/p>
一般的解决方案与特定的解决方案
,
如果
系统的阻尼
,
以一般的解决方案对应
的
振荡会随时间衰减
,
一段时间后
,
运动会达到一个稳定状态
,
系统将在一个恒
定的振幅与振动频率。这种运动
,
这就是所谓的强迫振动
,
被表示为特定的解决方案描述
(1
、
3
、
3
公式
)
。代入方程
(1
、
3
、
3)
为方程
(1
、
3
、
2),
位
移幅值
可以就是
(1
、
3
、
4
公式
)
。
When the dynamic force is
applied at a frequency much lower than the natural
frequency of the
system(wf/w<<1),the
response is quasi-static
、
The
response is proportional to the stiffness of the
structure,and the displacement
amplitude is close to the static
deflection
、
当动态力施
加在频率比系统的自然频率低得多
(
工作流
/
w
＜＜
1),
反应
quasi-static
、
the
响应对结构的刚
度成正比
,
与位移幅值接近静挠度。
When
the force is applied at a frequency much higher
than the natural frequency(wf/w)>>1),the
response is proportional to the mass of
the structure
、
当力
施加在频率比自然频率高得多
(
工作流
/ W)> > 1),
响应于结构的质量成正比。
When
the
force
is
applied
at
a
frequency
close
to
the
natural
frequency,the
displacement
amplitude
increases
significantly
、
The condition
at which wf/w=1 is known as
resonance
、
当力被施加在
一个频率接近的固有频率
,
位移幅值明显增加。在该条件下工作
流
/ W = 1
被称为共振。
1
、
3
、
2 Equations of Motion for Linear Multiple-
Degree-of-Freedom Systems
对于线性多自由度系统的运
动方程
In multiple
degree systems,an independent differential
equation of motion can be written for each
degree
of
freedom
、
The
nadal
equations
of
a
multiple
degree
system
consisting
of
n
degrees
of
freedom
may be written as(1<
/p>
、
3
、
5
公式
)where [m]
is a
symmetrical n*n matrix of mass,[c] is a
symmetrical n*n
matrix
of
damping
coefficient,and
{F(t)}
is
the
force
vector
which
is
zero
in
the
case
of
free
vibration
、
在多自由度系统
,
一个独立的运动微分方程可以为每
个自由度写的。纳达尔方程的多自由度系统组成的
n
个自
由度的可写为
(1
、
3
、
5
公式
)
在
[ M ]
就是一个对称的
n
×
n
矩阵的质量
,[C]
就是对称的
N * n
矩阵
,
阻尼系数
,
与
{F(t)}
力矢量就是零的情况下自由振
动。
Consider a system under
free vibration without
damping
、
The general solution
of Equation(1
、
3
、<
/p>
5) is assumed in the form of(1
、
3
、
6) where
angular frequency w and phase angle o are common
to all
x'
s
、
In
this
assumed
solution,o
and
c1
,c2,
、
、
、
,cn
are
the
constants
to
be
determined
from
the
initial
boundary conditions of the motion and w
is a characteristic value (eigenvalue) of the
system
、
《土木工程专业英语
》陈瑛
_
邵永波主编
_
全文经典翻译
考虑下一个无阻尼系统的自由振动方程
的一般解。
(1
、
3
< br>、
5)
的形式就是在假定
(
最佳
),
角频率与相位角
< br>O
就是
所有
X
< br>的。
常见的这种假设解
,O
与<
/p>
C1,C2,
……
,CN
就是从运动与
W
初始边界条件确定的常数就是一个特征
值
(
特
征值
)
的系统。
Substituting
Equation
(1
、
3
、
6)
into
Equation
(1
、
3
、
5)
yields
(1
、
3
、<
/p>
7
公式
)
where
[k]
and
[m]
are
the n*n
matrices,w2 is scalar,and {c} is the amplitude
vector
、
For nontrivial
solutions, solution to
Equation
(1
、
3
、
< br>7)
requires
the
determinant
of
{[
k]-w2[m]}*{c}={0}
、
The
expansion
of
the
determinant
yields
a
polynomial
of
n
degree
as
a
function
of
w2,the
n
roots
of
which
are
the
eigenvalues
w1,w2,Wn
、
(1
、
3
、
< br>6)
式代入公式
(1
、
3
、
5)
产量
(1
、
3
、
7
公式
)
其中
[K]
与
[]
就是
n * n
的矩阵
,W2
就是标量
,{C }
就是振
幅矢量
。对于非平凡解
,
解决方程
(1
、
3
、
7)
要求的行列式
{[K]-W2[M]}
*{C
}={0}
。行列式的扩展产生一个
n
次多
项式为
W2
的功能
,
其中
N
根的特征值
W1,W2,Wn
。
The
resulting
motion
is
a
sum
of
n
harmonic
motions,each
governed
by
the
respective
natural
frequency
w,written as (1
、
3
、
8
公式
)
、
由此产生的运动就是一个总与的
n
次简谐运动
,
有各自的自然频率
w,
写成
(1
、
3
、
8
公式
)
。
2
、
1
Structural Material
结构材料
;
2
、
1
、
1
Materials for Concrete and Mix Proportions
混凝土材料及配比
Concrete is
a
mixture of
aggregate,and
often controlled amounts of
entrained
air,held
together
by
a
hardened
paste
made
from
cement
and
water
、
Although
there
are
other
kinds
of
cement,the
word
cement
in common usage
refers to as portland
cement
、
A chemical reaction
between the portland cement and
water
causes concrete to harden to a stone-like
condition
、
This reaction is
called hydration
、
Hydration
gives
off
heat,known
as
the
heat
of
hydration
、
Because
hydration hardens concrete,freshly
placed concrete submerged
underwater
will
harden
、
When
correctly
proportioned,fresh
concrete
can
be
molded
into
nearly
any
size
or
shape
、
Upon
hydration
of
the
cement
by-
the
water,concrete
becomes
stone-like in strength,durability, and
hardness
、
混凝土骨料的
混合物
,
通常控制的夹带的空气的量
,
通过硬化浆体由水泥与水一起举行。虽然还有其她种类的
水泥<
/p>
,
在常见的词
,
指的就是波特兰水泥的水泥。
波特兰水泥与水之间的化学反应引起混凝土硬化的一块石头
像条
件。这个反应称为水化。水化发热
,
称为水化热。由于水化硬化混凝土
,
新浇混凝土水下会变硬。
当比例正确
,
新
鲜混凝土可以被塑造成
几乎任何尺寸或形状。对水泥水化的水
,
石混凝土成为像强度<
/p>
,
耐久性
,
与硬
度。
Portland
cement
、
波特兰水泥。
Portland
cement is the most commonly used modern
hydraulic cement
、
In this case,the word hydraulic is the cement's
characteristic
of holding aggregate
together by using water or other low-viscosity
fluids
、
Portland
cement is a carefully proportioned and specially
processed chemical
combination of
lime,silica,iron oxide,and
alumina
、
波特兰水泥就是最
常用的现代液压水泥。
在这种情况下
,
这个词就是水泥的特点的液压聚集在一起的控股通过
使用水或其她低粘度液体。波特兰水
泥就是一种精心相称
,
专门加工化学结合石灰、硅、铁氧化物、
氧化铝。
Water
、
水。
Unless test or
experience indicates that a particular water
source is
satisfactory,water should
be free from acids, alkalis,oils, and
organic
impurities
、
除非试验或经验表明一个特定的水源就是令人满意的
,
水应该就是免费的从酸、碱、油类、有机杂质。
Aggregate
、
骨料。
Inert filler
materials(usually sand and stone or gravel) make
up between 60 and 80 percent of
the
volume of normal concrete
、
Aggregate is often washed when impurities are
found that can retard
cement hydration
or deteriorate the concrete's
quality
、
All aggregate is
screened to ensure proper
size
gradation,because
concrete
differs
from
other
cement-water-aggregate
mixtures
in
the
size
of
its
Aggregate,
'the
aggregate'
s
physical
and
chemical
properies
alse
affect
concrete
properties
aggregate size, shape, and grade
influence the amount of water
required
、
For example
limestone
aggregate requires more water
than marble aggregate of similar
size
、
Aggregate surface
texture
influences
the
hond
between
the
aggregate
and
the
cement
paste
、
In
properly
mixed
concrete
,the
paste
surrounds each
aggregate particle and fills all spaces between
the particles The elastic properties
of
the aggregate influence the elastic properties of
the concrete and the paste
’
s
resistance to
shrinkage
、
Reactions
between
the
cement
paste
and
the
aggregate
can
either
improve
or
harm
the
bond
between the two consequently,the
concrete's quality
惰性填料材料
(
通常就是沙子与石头或砾石
)
组成
60 ~ 80%
的普通混凝土的体积。聚合通常就是当杂质洗发现可<
/p>
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
以延缓水泥水化或恶化
混凝土的质量
。所有骨料就是筛选以确保适当的大小分级
,
因为混凝土不同于
其她水泥水骨料混合物在大小它的
骨料
,
骨料的物理与化学性能也将影响具体的属性集料尺寸
,
形状<
/p>
,
与年级影响数量的水要求。例如石灰石骨料要
< br>求更多的水比大理石骨料大小相近的。骨料表面纹理影响本田
< br>在聚合与水泥膏。在正确地拌混凝土
,
围绕每个骨料颗粒
与粘贴填充粒子之间的所有空间弹性性能的总体影响的
弹性性能混凝土与膏的抗收缩。反
应之间的水泥粘贴与骨料可以改善或伤害她们的关系
因此
,
混凝土的质量
Admixtures
、
外加剂。
Admixtures
are added to the concrete mixture to accelerate or
retard the initial set, improve
workability,
reduce
water
requirements,
increase
strength,improve
durability,decrease
permeability, and impart other
properties
、
They usually
cause a chemical reaction within
the
concrete
、
Admixtures
admixtures
are
normally
classified
into
accelerating
admixture,set-retarding
admixtures
,air-entraining
,pigments,agents,plasticizers,fly
ash,silica
fume,color
pigments,
and
miscellaneous
materials
、
Many
admixtures
fall
into
more
than
one
classification
、
<
/p>
外加剂的加入加速或延缓的初始设置
,
混
凝土拌合物改善与易性
,
减少水的要求
,
增加强度
,
提高耐久性
,
降低渗
透率
,
并赋予其它特性。她们通常会产生化学反应
,
在混
凝土外加剂。外加剂通常分为速凝剂
,
缓凝外加剂
,
引气
,
颜料
,
剂
,
增塑剂
,
粉煤灰
,
硅粉
,
色素
,
杂项材料。许多
外加剂陷入一个以上的分类。
2
、<
/p>
1
、
2 desirable
concrete property
理想的混凝土的性能
1
、
Plastic
Concrete
塑性混凝土
Plastic
Concrete
is
a
concrete
in
a
relatively
fluid
state
that
is
readily
molded
by
hand,like
a
lump
of
modeling
clay
、
A
plastic
mix
keeps
all
the
grains
of
sand
and
the
pieces
of
gravel
or
stone
encased
and held in
place
、
The degree of
plasticity influences the quality and character of
the finished
product
、
< br>塑性混凝土就是混凝土在相对流体状态
,
易于成型用手<
/p>
,
像一块橡皮泥。塑料混合使砂的谷物
与碎石或石包裹与地点举行的程度、可塑性影响质量与成品的品质。
The workability of a concrete
mix gives a measure of the ease with which fresh
concrete can be
placed and
compacted
、
The concrete
should flow reading into the form and go around
and cover the
reinforcement ,the mix
should retain , its consistency and the
aggregates should not
segregate
、
A mix
with
hig
workability
is
needed
where
sections
are
thin
and/or
reinforcement
is
complicated
and
congested
、
混凝土混合物的加工性的容易性給出了一個衡量可以放置新鮮混凝土与壓實。
混凝土流量讀數進入的形式与去
走一走
,
覆蓋加固
,
組合應保留
,
它的一致性与總量不應
segregate
、
A
混合
HIG
加工
性就是必要的
,
其中部分就是
薄的与<
/p>
/
或複雜的加固与擁擠。
The
main
factor
affecting
workability
is the
water content
of
the
mix
、
Plasticizer
will
increase
workability The size of aggregate, its
grading and shape, the ratio of coarse to fine
aggregate and
the aggregate-to-cement
ratio also affect workability to some
degree
、
影響加工性的主要因
素就是混合的水含量。增塑劑總大小將增加可操作性
,
其分級<
/p>
形狀
,
粗到細
集料与水泥的總比的比例也在一定程度上影響可操作性。
Hardened concrete is the end product of any
concrete design
、
the
essential
properties thati it must have
are strength,durability ,and watertinghtness
硬化混凝土的任何具体的设计必不可少的最终产品
,
它必須就是強度
,
耐用性与水密性
Strength
、
强度。
the
concrcte's
ability
io
resist
a
load
in
compression,
flexure
or
shear
is
a
measure
of
its
strength
、
Concrete strength is largely determined
by the ratio of water to cement in the mixture
and curing
condition
、
混凝土的抗压缩能力
IO
负载
,
弯曲或剪切就是衡量其强度。
混凝土的强度在很大程度上取
决于水在混合水泥的配
比与固化条件。
Durability
、
耐久性。
Climate and
weather affect durability
、
thus , the concrete's abilities to resist the
effects of
wind, frost
,snow,ice,abrasion,and the chemical reaction of
soils or salts are a measure of its
durability
、
as
the water to cement ratio increases,durability
decreases correspondingly
气候与天气影响耐久性。因此
,
本混凝土的抗风
,
< br>霜
,
雪
,
冰
,
磨损的影响
,
< br>与
土壤或盐的化学反应就是衡量其耐久性。当水灰比的
增大
,
耐久性降低相应
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
Durability
should
be
a
strong
consideration
for
concrete
structures
expected
to
last
longer
than
five
years
、
Air-
entrained concrete has improved freeze-that
durability
耐久性应就是一个重要的考虑混凝土结构的预期持续超过五年。
加气混凝土提高了冻结耐久性
Watertightness
、
水密性。
Tests show
that the watertightness of a cement paste
depends on the water to cement ratio
and
the
extent
of
the
chemical-
reaction
process
between
the
cement and
water
、
The watertightness
of air-entrained concrete is superior
to that of nonair-entrained
concrete
、
測試表明
,
水泥的防水貼取決於水與水泥之比与化學反應的程度之間的水泥与水
的過程。空氣夾帶的水密性混凝
土優越的夾帶
nonair
的混凝土。
The strength
and deformation characteristics of concrete thus
depend on the grade and type of
cement,aggregates,admixtures,water to
cement ratio, environmental conditions and
curing
、
Plain
concrete after preparation and placement needs
curing to attain strength
、
The increase
of strength with its age
during curing is considered to be marginal after
28 days
、
因此
,
混凝土的強度与變形特性取決於等級与種類的水泥
,
骨料
,
外加劑
,
水與水泥之比
,
環境條件与固化。
普通
混凝土製備後安置需要固化達到強度。強度的增加
,
其年齡
在固化過程中被認為就是邊緣
28
天后。
Plain
concrete
is
very
good
in
compression
but
weak
in
tension
、
That
is
why
steel
is
used
as
reinforcing
material to make
the composite sustainable in tension
also
、
Plain concrete,thus
when reinforced
with steel bars in
appropriate locations is known as reih forced
concrete
、
普通混凝土就是
很好的壓縮
,
但緊張弱。因此鋼被用作增強材料
,
以在拉伸的複合可持續也。普通混凝土
,
因此
,
當收服被迫與適當的鋼筋位置被稱為遏制強
制式混凝土。
2
、
< br>1
、
3 proportioning
concrete mixtures
配比混凝土混合物
the various components of a mix are
proportioned so that the resulting concrete has
adequate
strength,proper
workability
for
placing,
and
low
cost
、
The
third
calls
for
use
of the
minimum
amount of cement
that will achieve adequate
properties
、
各个组成部
分的混合比例就是使所产生的混凝土具有足够的强度
,
适当可行
放置
,
且成本低。
使用的最小水泥用量
,
将获得足够的性能。
The
two
primary
methods
used
to
proportion
a
mix
design
are
the
trial-batch
method
and
the
absolute-
volume
method
、
Proportions
of
ingredients
for
concrete
should
be
selected
to
make
the
most
economical
use
of
available
materials
that
will
produce
concrete
of
the
required
workability,
durability, and strength basic
relationships already established and the
laboratory tests provide
guidance for
optimum combinations, Recommended and typical
mixes of concrete for various
types
or
classes
of
work
will
detcermine
how
to
proprtion
concrete
mix,
factors
affecting
this
include:
(l) water to cement
ratio, (2) type andd size of aggregate (3) air or
nonair-entrained concrete, and
(4)
slump of the mix
、
比例混合设计使用的两种主要方法就是审批方法与绝对体积法。
混凝土的配料比例应选
择使现有材料的最经济的
使用将生产所需的加工性
,
耐久性混凝土
,
强度基本已经建立的关系与实验指
导最佳组合
,
推荐与各种具体的典型
的
混合工作类型或类将
detcermine
如何比混凝土配合比
,
因素影响包括
:(1)
的水灰比
,(2)
骨料的类型与大小
(3)
或空气夹带与
nonair
混凝土
,(4)
混合料的坍落度。
The water to cement ratio is
determined by the strength, durability,and
watertightness requirements of the
hardened concrete
、
Strength,
durability and watertightness are
usually
specified
by
the
structural-design
engineer,
but
a
tentative
mix
proportion
can
be
determined
from knowledge of a prior job
。
Always remember that a
change in the water to cement ratio changes
the
characteristics
of
the
hardened
concrete
、
In
addition
to
the
water
required
for
hydartion,
water
is
needed
for
wetting
the
surface
of
the
aggregate
、
As
water
is
added,
the
plasticity
and
the
fluidity
of the mix increase
(i
、
e
、
, its workability improves), but the strength
decreases because of the
larger volume
of voids created by the free
water
、
水灰比的确定的强度
,
耐久性
,
与硬化的混凝土的水密性要求。强度
,
耐久性
,
水密性通常就是由结构设计工程
师指定
,
但初步配合比可以从现有的工作知
识确定永远记住
,
在换水灰比的变化硬化的混凝土的特性。此外
,
所需
的
hy
dartion,
水就是需要的润湿表面的总与。
由于水增加<
/p>
,
塑性与混合增加流动性
(
即
,
其与易性提高
),
但强度下
降
,
因为
空隙体积较大所产生的游离水。
The better
the gradation of the aggregate,
i
、
e
、
the smaller of the volume of voids, the less
cement paste is needed to fill these
voids
、
Fine
aggregates are used to fill the spaces between the
coarse
aggregate
particles
and
to
increase
the workability
of
the
mix
、
Aggregate
that
does
not
have
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
a large grading gap nor an
excess of any size gives a smooth grading curve
produces the best mix
、
骨料的级配越好
,
即体积更小空隙
,
减少水泥浆体需要填补这些空隙。
细骨料的使用填充
粗集料颗粒之间的空间
与增加组合的加工性。总没有一个大的等级差距也不就是超出尺寸
提供一个平滑的级配曲线产生最好的组合。
The
maximum
size
of
coarse
aggregate
that
produces
concrete
of
maxi
strength
for
a
given
cement
content
depends upon the
aggregate source as well as the aggregate shape
and grading; thus, in most cases,
a
decrease
will
take
place
in
the
overall
cost
、
The
larger
the
maximum
size
of
the
coarse
aggregate,
the
less
paste
(Water,
cement
and
usually
entrained
air)
that
is
required
for
a
given
concrete
quality
、
The maximum size of aggregate should
not exceed one-fifth the minimum dimension of the
member or
three-fourths the space
between reinforcing bars
、
For pavement or floor slabs, the maximum Size of
aggregate should not exceed one-third
the slab thickness
粗骨料产生的对于一个给定的水泥含量最大强
度混凝土的最大大小取决于骨料来源以及骨料形状与分级
;
因此
,
在大多数情况下
,
< br>减少将在总成本。
较大的粗骨料的最大尺寸
,
不酱
(
水
,
水泥与通常夹带的空气
),
对于一个给定的
混凝土质量要求。
骨料的最大尺寸不超过五分之一的最小尺寸的成员或四
分之三钢筋之间的空间。
路面或水泥板
,
骨料的最大尺寸不应超过三分之一的板坯厚度
1
、
3 Structural
Dynamics
结构动力学
Chapter 2
、
Structural Material
土木工程材料
2
、
1 Materials
for Concrete and Mix Proportion
砼材料及配比
2
、
2 Properties
of Concrete
砼的性能
2
、
2
、
1
compressive strength
抗压强度
1
、
cube
compressive strength
立方体抗压强度
the
cube
compressive
strength
of
the
concrete,f,is
given
in
terms
of
the
characteristic
compressive
strength of
150mm size cubes tested at 28
days
、
Figure
2
、
1shows an idealized normal
distribution
of the values of
compressive strength for a sizeable number of test
cubes
、
(
第一题答案大概在这
)The
horizontal axis represents the values
of compressive strength
、
This is also termed as
frequency
、
The
average
of
the
values
of
compressive
strength(mean
strength)is
represented
as
f
、
the
characteristic strength is defined as
the strength of the concrete below which not more
than 5% of
the test results are
expected to fall
、
The value
of the normal
distribution
、第二题答案大概在这
)
立方体抗压强度的混凝土
,
楼给出为
150mm
的尺寸在
28
天测试的多维数据集的特征抗压强度。图
2
、
< br>1
显示了
一个理想化的常态分布相当数量的立方体试块的
抗压强度值。
横轴表示抗压强度的值。
这也被称为频率。
抗压强
度的值的平均值
(
平均强度
)
表示为
f
。
特征强度被定义为混凝土的强度不超过
5
％的测试结果低于该预计将下降。
常态分布的值。
Concrete is graded on the basis of
its characteristic compressive strength and
expressed in MPa
、
The grades are designated by one letter
C and a number from 15 to 18 indicating the
characteristic
strength may be
different in different
countries
、
混凝土的基础
上
,
其特征抗压强度分级
,
以
MPa
表示。成绩指定一个字母“
C
”与一个数字从
15
到<
/p>
18,
表明特征
强度可能在不同的国家就
是不同的。
2
、
prismatic
compressive strength
棱柱抗压强度
the
prismatic
compressive
strength
of
concrete
is
close
to
the
axial
compressive
strength
of
concrete
in
column
、
Prismatic specimens
with a height-to-width aspect ratio of 3 to 4 are
adopted
、
的棱柱形的混凝土
的抗压强度就是混凝土柱的轴心抗压强度。
的高度与宽度的纵横比为
3
?
4
的棱柱形样品通
过。
2
、
2
、
2 tensile strength
抗拉强度
the tensile
strength of concrete can be expressed as follows;
混凝土的拉伸强度可以表示如下
;
1
、
axial tensile strength
轴向抗拉强度
it
is
measured by testing
prismatic
specimens
under direct tension
、
there
are
considerable
difficulties in
determining the true tensile strength of concrete
、
minor misalignment and
stress
concentration in the graping
devices are apt to mar the
result
、
它就是测量
,
由测试棱柱标本的直接拉伸下
,
有相当大的困难
,
确定真正的混凝土抗拉强度。
轻微的未对准与应
力集中在
graping
装置容易擦伤的结果。
The
following
expression
gives
an
extimation
of
axial
tensile
strength
of
concrete
from
its
characteristic cube compressive
strength
、
下面的表达式给
出其特征立方体抗压强度混凝土轴向拉伸强度的
DOA
估计。<
/p>
2
、
splitting
tensile strength
劈裂抗拉强度
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
the result of split-cube test is a
measure of the tensile strength of concrete ,a
150mm
concrete
cube,
the
same
as
the
one
used
for
cube
compressive
test
,is
inserted
in
a
compression
testing
machine
、
Pads are
inserted between the compression platens of the
machine and the cube to equalize
and
distribute
the
pressure
、
It
can
be
shown
that
in
an
elastic
cube
so
loaded,
a
nearly
uniform
tensile
stress
of
magnitude
f=2p/
exists
at
the
right
angle
to
the
plane
of
loading
application,
correspondingly, such cube, when
tested, splits into two halves along that plane,
at a stress f that
can be computed from
the equation f ,where P is the applied compressive
load at failure,and a is the
length of
cube
、
(
第四题答案大约这
)
劈裂抗拉强度分割多维数据集测试的结果就是一定程度的混凝土的
拉伸强度
,150
毫米
混凝土立方体
,
立方体抗压强度试验使用了一个相同
,
被插入在压缩试验机。
垫之间插入机
器的压盘与多维数据集
的压力平衡与分发。可以证明
,
在一个弹性的多维数据集以便加载
,F =2
π
/
在合适的角度的平面的加载应用程序
存在
,
相应地
,
这样的多维数据集
,
在测试时
,
被分为两半沿该平面几乎均匀的拉伸应力级
,
在应力
f
以从方程
f,
可
以计算
,
其中
P
就是破坏时所施加的压缩载荷
,a
为立方体的长度。
2
、<
/p>
2
、
3the modulus of
elasticity
弹性模量
the
modulus
of
elasticity
is
determined
from
a
low
cycle
loading
test
of
prismatic
specimen
、
The
loading
is limited to a
maximum value of
0
、
5f
、
the loading-unloading cycle is repeated 5 to 10
times
、
弹性模量来确定从一
个低的棱柱形试样的循环载荷试验。装载被限制到最大值为
0
、
5F
。装载
-
卸载循环反复
进行
5
?
10
次。
The
modulus of elasticity obtained from low cycle
loading test is given by the following
equation(
第
三题大概在这
)
低循环载荷试验从得到的弹性模量就是由下面的公式给出
2
、
2
、
4 shrinkage of
concrete
混凝土收缩
any
workable concrete mix contains more water than is
needed for hydration
、
If the
concrete is
exposed to air , the large
part of this free water evaporates in time , the
rate and completeness of
drying
depending on ambient temperature and humidity
conditions
、
As the concrete
dries, it shrinks
in
volume,
probably
due
to
the
capillary
tension
that
develops
in
the
water
remaining
in
the
concrete
、
Conversely, if dry concrete is immersed
in water, it expands, regaining much of the volume
loss from
prior
shrinkage
、
Shrinkage, which
continues at a decreasing rate for several months,
depending on
the
configuration
of
the
member,
is
a
detrimental
property
of
concrete
in
several
respects
、
When
not
adequately controlled,
it will cause unsightly and deleterious cracks, as
in slabs, walls, etc
、
in
structures that are statically
indeterminate(and most concrete structures are),
it can cause large
and harmful
stresses
、
In prestressed
concrete it leads to partial loss of initial
prestress
、
For
these reasons, it is essential that
shrinkage be minimized and
controlled
、
任何可行的
混凝土配合比中含有较多的水比需要水化。
如果混凝土暴露于空气中
,
这个自由水分蒸发时间的很
大一部分
,
取决于环境温度与湿度条件下的干燥速率与完整性。作为具体的干燥
,
但在体积收缩
,
可能就是
由于在
剩余的水在混凝土中的毛细管张力
,
开发。相反
,
如果在水浸泡干燥混凝土
,
膨胀
,
重新获得与前收缩的体积
损失。
收缩率
,
持续数个月的下降速度
,
根据配置的部件
,
< br>就是在以下几个方面的混凝土产生有害的属性。当没有足够的
控制
,
它会造成难瞧的与有害的裂缝
,
如地砖
,
墙面
,
< br>超静定结构中
(
与最混凝土结构
)
等
,
它可能会导致大的与有害
的应力。预应力混凝土初始预应力部分损失。由于这些原因
,
至关重要的就是
,
最小化与控制收缩。
1
、
effect
of cement and water contents on shrinkage
水泥与水的含量对收缩率的影响
water content is probably the largest
single factor influencing the shrinkage of paste
and
concrete
、
Typical shrinkage values for concrete specimens
with a 5 to 1 aggregate-cement ratio are
0
、
04,
0
、
06,
0
、
075
and
0
、
085
percent
for
water-cement
ratios
of
0
、
4
,0
、
5,0
、
6
and
0
、
7,
respectively
、
One
of
the
reason
is
that
the
density
and
composition
of
calcium
silicate
formed
at
different
water-cement
ratios may be slightly
different
、
In general, a
higher cement content increases the
shrinkage of concrete; the relative
shrinkages of neat paste, mortar and concrete may
be of the
order
of about 5,2
and 1
、
含水量可能就是最大的单一因素影响浆与混凝土的收缩。
5<
/p>
合
1
水灰比混凝土试件典型的收缩值就是
0
、
04,0
、
06,0
、
075
< br>％与
0
、
085
％的水胶比为
0
、
4,0
、
5,0
、
6
与
0
、
7,
分别。的原因之一就是
,
形成在不同的水与水
泥比
硅酸钙的密度与成分可能会略有不同。
一般情况下
,
较高的水泥含量
,
增
加混凝土的收缩
,
相对整齐的泥浆
,<
/p>
砂浆与
混凝土的收缩可能就是
5,2
与
1
的顺序。
Fineness
of
cement
seems
to
be
a
factor
in
shrinkage
and
particles
coarse
than
No
、
200
sieve,
which
react
with
water
very
slowly,
have
a
restraining
effect
similar
to
that
of
aggregate
、
Thus,
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
high-early-strength
cement,
which
is
finely
ground,
shrinks
about
10
percent
more
than
normal
cement
、
Low-heat and Portland-pozzolan cements
shrink a further 20 and 35 percent,
respectively
、
This is
believed to be caused by larger
quantities of calcium silicate, the shrinking
component, present in
them
、
水泥细度
,
似乎就是一个因素
,
在收缩率与粗颗粒比
200
号筛
,
与水发生反应很慢
,
有抑
制效果
,
类似的集料。
因此
,
高早强水泥
,
细磨
,
收缩约
10
％<
/p>
,
比常规的水泥。低热量与波特兰火山灰水泥进一步缩小
20
％与
35
％
,
分别。这被
认为就是由于较大数量的硅酸钙
,
收缩组件
,
呈现在其中。
2
、
type and
gradation of
aggregate
集料的类型与层次
As stated previously
,the
drying shrinkage of concrete is a fraction of
that of neat
cement
because
the aggregate
particles not only dilute the paste but also
reinforce it against
contraction
、
It has
been
shown
that
when
readily
compressible
aggregate
is
used,
concrete
will
shink
as
much
as
neat
cement,
and that expanded
shale leads to shrinkage one-third more than that
of ordinary aggregate
、
Steel
aggregate
on
the
other
hand,leads
to
shrinkage
one-
third
less
than
that
of
ordinary
concrete
、
In
general
terms the elastic
properties of aggregate determine the degree of
restraint offered
、
The size
and
grading of aggregate do not, by
themselves, influence the magnitude of shrinkage,
but an aggregate
incorporating larger
sizes permints the use of a mix with less cement
and hence a lower shrinkage
、
Increasing the maximum aggregate size
and thereby the aggregate content by 20 percent of
the total
volume of the concrete will
ensure a substantial decrease in
shrinkage
、
如前所述
,
混凝土的干燥收缩的影响就是纯水泥的一小部分
< br>,
因为聚集体颗粒不仅稀糊
,
而
且也加强反收缩。它
已被证明
,
当可压
缩合容易地被使用时
,
将热收缩不亚于纯水泥混凝土
,
膨胀页岩导致收缩率的三分之一超过普通
骨料。
钢合另一方面
,
导致收缩小于普通混凝
土的三分之一。
总体而言
,
集料的弹性
性质决定提供的限制程度。
集
料的大小与分级本身
,
不这样做
,
影响收缩的幅
度
,
但就是汇聚将较大尺寸
permi
nts
以较少的水泥
,
从而以较低的<
/p>
收缩率的混合使用。最大骨料粒径的总含量
,
从而增加混凝土的总体积的
20
％
,
以确保收缩率大幅下降。
3
、
effect of
admixtures
as
can
be
predicted
for
the
effect
of
water-cement
ratio
on
shrinkage,
admixtures
that
increase
the
water requirement of concrete increase
shringkage and those that decrease the water
requirement
decrease
it
、
Calcium
chloride
in
the
amount
ofen
added
as
an
accelerator
—
2
percent
by
weight
of
the
amount of
cement
—
may increase drying
shrinkage by as much as 50 percent
、
(
第五题
)
可以预见
的收缩
,
增加混凝土的收缩与减少需水量减少
< br>,
从而增加了需水量的外加剂水灰比的效果。
氯化钙的量
奥
芬水泥的用量
(
重量
)
作为促进剂的
2
％的增加<
/p>
,
可能会增加干燥收缩率高达
50
％。
The
over-all
effect
of
the
use
of
air-entrained
concrete
is
not
to
increase
shrinkage
、
Some
admixtures,
if
used
in
somewhat
larger
than
normal
doses,
do
increase
shrinkage
greatly
and
care
must
be
exercised
in the
proportioning
、
过度
所有加气混凝土的使用效果就是在不增加收缩。一些外加剂
,
如
果略大于正常剂量使用
,
不增加收缩大大
,
必
须小心谨慎配比。
2
、
2
、
5 creep of concrete
混凝土徐变
Creep is the slow deformation of a
material over considerable length of time at
constant stress
or
load
、
The
nature
of
the
creep
process
is
shown
schematically
in
figure
2
、
4
、
this
particular
concrete
was
loaded
after
28
days
with
resulting
instantaneous
elastic
strain
、
If
the
same
stress
is
kept
for
a period of time, and additional strain
due to creep effect can be
recorded
、
If the sustained
load
is removed, the strain decreases
immediately by an amount equal to the elastic
strain at the given
age;
this
is
generally
lower
than
the
elastic
strain
on
loading
since
the
elastic
modulus
has
increased
in
the intervening period
、
This
instantaneous recovery is followed by a gradual
decreased in the
intervening
period
、
This instantaneous
recovery is followed
by
a
gradual decrease in strain,
called
creep recovery
、
This recovery is not complete because creep is not
simply a reversible
phenomenon
、
渐变就是缓
慢变形的材料在恒定应力或负载在相当长的时间。
潜变过程中的性质
,
就是示意性地示出在图
2
、
4
中。这个特殊的混凝土被加载后
28
天产生的瞬时弹性应变。如果在一段时间内保持相同的应力
,
并且可记录
,
可额外的压力
< br>,
由于蠕变效应。如果持续负载被删除
,
应变减小立即金额相等于在给定的年龄弹性应变
,
这就
是普
遍低于上加载的弹性应变的弹性模量
,
因为在此期间增加了。瞬时恢复之后的逐渐减少在此期间。瞬时恢复之后
逐渐减少<
/p>
,
应变
,
蠕变恢
复。这种复苏就是不完整的
,
因为蠕变不单纯就是一个可逆的现
象。
Creep
does
not
include
any
immediate
elastic
strains
caused
by
loading
or
any
shrinkage
or
swelling
caused by moisture
changes
、
When a concrete
structural element is dried under load, the creep
that
occurs is one to two times as
large as
it
would
be under constant moisture
conditions
、
Adding
normal
drying
shrinkage
to
this
and
considering
the
fact
that
creep
can
be
several
times
as
large
as
the
elastic
《土木工程专业英语》陈瑛
< br>_
邵永波主编
_
全文经典翻译<
/p>
strain on loading, it may be
seen that these factors can cause considerable
deflection and that they
are of great
importance in structural
mechanics
、
潜变不包括通
过加载或任何收缩或膨胀湿度变化引起的任何直接引起的弹性应变。
当用在负载下的混凝
土结构
元件
,
发生蠕变的一到两倍大<
/p>
,
因为它会在不变的湿度条件下。
添加正
常的干燥收缩于此
,
考虑潜变的事实
,
还可以
数次上加载的弹性应变大时
,<
/p>
可以瞧出
,
这些因素可能会导致相当大的
挠度与结构力学中就是非常重要的。
1
、
factors
influencing creep
影响潜变因素
concrete
that
exhibits
high
shrinkage
generally
also
shows
a
high
creep,
but
how
the
two
phenomena
are
connected
is
still
not
understood
、
Evidence
suggests
that
they
are
closely
related
、
When
hydrated
cement is
completely dried, little or no creep occurs; for a
given concrete the lower the relative
humidity, the higher the
creep
、
混凝土
,
具有较高的收缩率一般也显示出较高的蠕变
,
但如何连接这两种现象仍然没有完全理解。有证据表明
,
她
们就是密切相关的。当水合的水泥完全干燥
,
很少或没有发生蠕变
,
对于一个给定的混凝
土的低的相对湿度下
,
较
高的蠕变。<
/p>
Strength
of
concrete
has
a
considerable
influence
on
creep
and
within
a
wide
range
creep
is
inversely
proportional to
the strength of concrete at the time of
application of load
、
From
this it follows
that creep is closely
related to the water-cement
ratio
、
There is no doubt
also that the modulus of
elasticity of
aggregate controls the amount of creep that can be
realized and concretes made with
different aggregates exhibit creep of
varying magnitudes
、
< br>混凝土强度具有相当大的影响潜变与在宽范围内的潜变负载的应用时混凝土的强度成反比。从这一点如下< /p>
,
潜变
就是密切相关的水灰比。这就是毫
无疑问也集料的弹性模量控制的蠕变量
,
可实现混凝土采用不同
的聚合表现出
不同程度的潜变。
Experiments
have
shown
that
creep
continues
for
a
very
long
time;
detectable
changes
have
been
found
after as long as 30
years
、
The rate decreases
continuously; however, it is generally assumed
that
creep
tends
to
a
limiting
value
、
It
has
been
estimated
that
75
percent
of
20-year
creep
occurs
during
the
first year
、
(
第六题
)
实验已经表明
,
潜变持续很长的时间
,
只要
30
年后
,
已发现可检测的变化。率连续减小<
/p>
,
但就是
,
它一
般假设
,
潜变
趋向于限制值。据估计<
/p>
,75
％
,20
年的潜变发生在第一年期间。
2
、
effects of
creep
潜变的影响
creep
of
plain
concrete
does
not
by
itself
affect
strength,
although
under
very
high
stresses
creep
hastens the approach of the limiting
strain at which failure takes
place
、
The influence of
creep on
the ultimate strength of a
simply supported reinforced concrete beam
subjected to a sustained load
is
insignificant,
but
deflection
increases
considerably
and
may
in
many
cases
be
a
critical
consideration in
design, another instance of the adverse effects of
creep is its influence on the
stability
of the structure through increase in deformation
and consequent transfer of load to other
components
、
Thus,
even
when
creep
does
not
affect
may
be
extremely
serious
as
fat
as
the
performance
of the structure
as a whole is concerned
、
普通混凝土的潜变不影响本身的实力
,
虽然非
常高应力下潜变加快极限应变的方法
,
在故障发生。
潜变极限强
度的钢筋混凝土简支梁受持续负载的影响就是微不足道的
,
但偏转大大增加
,
并在许多情况下可能就是一个关键
的设计考虑
,
潜变的不利影响的另一个实例就是它的影响力通过增加变形与由此产生的负载转移到其她组件的结
构的稳定性。因此
,
即使当潜变不影响可能表
现为脂肪的结构作为一个整体而言就是极为严重的。
The
loss
of
prestress
due
to
creep
is
well
known
and
accounted
for
the
failure
of
all
early
attempts
at
prestressing
、
Only
with
the
introduction
of
high
tensile
steel
did
prestressing
become
a
successful
operation
、
The
effects of creep may thus be
harmful
、
On the whole,
however, creep unlike shrinkage
is
beneficial in relieving stress concentrations and
has contributed to the success of concrete as
a structural
material
、
由于蠕变预应力
的损失就是众所周知的
,
占所有早期的尝试中失败的预应力。<
/p>
只有引进高强度钢
,
预应力成为一个
成功的操作。蠕变的影响
,
因此可能就是有
害的。但就是
,
就整体而言
,
潜变不同收缩率
,
有利于缓解应力集中
,
作
为结构材料与混凝土的成功作出了贡献。<
/p>
Questions
1
define characteristic strength of
concrete
、
定义混凝土的强度特性。
2 how
and when is the characteristic compressive
strength f determined?
如何以及何时确定特征抗压强度确定
的
F
？
3
how to determine the modulus of elasticity of
concrete?
《土木工程专业英语》陈瑛
_
邵永波主编
_
全文经典翻译
如何确定混凝土的弹性模量不？
4 how to test the splitting strength of
concrete?
4
混凝土劈裂强度如何测试？
5 how to control shrinkage of concrete?
5
如何控制混凝土收缩？
6 describe the property of concrete
creep based on figure
2
、
4
、
<
/p>
6
描述混凝土的质量的徐变根据图
2
、
4
。
7 what are the factors influencing
creep of concrete?
7
哪些因素影响混凝
土的徐变？
(
宽范围内的潜变负载
,<
/p>
湿度等因素
)
1)
内在因素
──
混凝土组成成分
a)
水泥用量越多
,
徐变越大
;b)
水灰比越大
,
徐变越大
;c)
骨料越坚硬
,
徐变越小。
2)
环境因素
──
养护时的温度、湿度
养护时温度高、湿度大
,
徐变越小。<
/p>
3)
应力条件
──
混凝土的应力大小
混凝土的应力越大
,
徐变也越大。
(5)
徐变对混凝土结构与构件的工作性能的影响
由于混凝土的徐变
,
会使构件的变形增加
;
在预应力混凝土结构中会造成预应力损失。
2
、
3 Steel
Materials
钢材料
2
、
3
、
1
steel properties
钢的性能
Structural
steel
is
an
important
construction
material
、
It
possesses
attributes
such
as
strength,
stiffness, toughness, and ductility
that are very desirable in modern
constructions
、
Strength
is
measured
in
terms
of
the
matrrial
’
s
yield
strength,
f
、
the
common
steel
strength
grades
used
in
constructions
are
Q235,Q345,Q390
and
Q420
、
The
stress-strain
curve
of
steel
Q235
from
uniaxial
coupon test is shown in figure
2
、
5
、
it is seen that the proportional limit stress
(marked at point
A) and the yield
stress(marked at point B) are very close, and thus
the small difference between the
two
stresses can be ignored
、
The
stress-strain curve also shows a small plateau
beyond the elastic
limit and then an
increase in strength due to strain
hardening
、
At point E,
necking occurs and the
specimen fails
rapidly to fracture
、
结构钢就是一种重要的建筑材料。它具有的属性
,
如强
度
,
刚度
,
韧
性与延展性
,
在现代建筑中就是非常理想的。
< br>
强度测量的材料的屈服强度
< br>。
共同建设中使用的钢材强度等级
Q235,Q345,
Q390
与
Q420
。
Q235
钢的应力
-
应
变曲线从单轴券试验如图
2
、
5
所示。
可以瞧出
,<
/p>
比例极限应力
(
在点
A
处标记
)
与屈服应力
(
标记为
B
点处
)
都非常
接近
,
因此
,
两者之间的应力小的差别可以忽略不计
。
应力
-
应变曲线也示出的一个小
高原超过弹性极限
,
则由于
应变硬化的
强度增加。在
E
点时
,
缩颈与标本未能迅速断裂。
The
stress-strain
curve
of
high
strength
steel
materials
is
shown
in
figure
2
、
< br>6
、
there
is
no
clear
yielding
point
in
the
curve,
and
the
plastic
flowing
is
almost
invisible
、
The
yield
stress
is
determined
by
the
0
、
2%
of
offset
strain
method
、
In
the
coupon
test,
the
specimen
is
fractured
suddenly
and
there
is no
remarkable necking
phenomenon
、
高强度钢材料的应力
-
应变曲线<
/p>
,
在图
2
、
6
中示出。
有在曲线没有明显的屈服点
,
塑性流动几乎就是不可见的。
由
0
、
2
％的偏移应变法
确定的屈服应力。在试验
,
试样突然断裂
,
并没有显着的颈缩现象。
Stiffness
is
the
ability
of
a
material
to
resist
deformation
、
It
is
measured
as
the
slope
of
the
materal
’
s stress-
strain curve
、
Stiffness does
not vary appreciable for different steel
grades
、
Toughness
is the ability of a material to absorb
energy before failure
、
It is
measured as the area under the
material
’
s
stress-strain curve
、
刚度就是一个材料抵抗变形的能力。这就是测量的材料的应力
-
应变曲线的斜率。刚度不随可观的不同的钢
种。韧性就是在
出现故障前的材料吸收能量的能力。这就是测量材料的应力
-
应变曲线下的面积。
Ductility
is
the
ability
of
a
material
to
undergo
large
inelastic,
or
plastic,
deformation
before
failure
、
It is
measured in terms of percent elongation or percent
reduction in area of the specimen
tested
in
uniaxial
tension
、
Ductility
generally
decreases
with
increasing
steel
strength
、
Ductility
is
a
very
important
attribute
of
steel
、
The
ability
of
structural
steel
to
deform
considerably
before
failure by fracture allows an
indeterminate structure to undergo stress
redistribution
、
Ductility
also enhances the energy absorption
characteristic of the structure, which is
extremely important in
seismic
design
、
延展性的能力构成重
大故障前进行大无弹性
,
或塑料
,
变形。据测定
,
在％的伸长率或在单轴拉伸
测试的试样
《土木工程专业英语》陈瑛
_
邵永波主编
_
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面积减少百分之。
延展性普遍提高钢的强度降低。
钢的延性就是一个很重要的属性。
结构钢变形的能力大大骨折
发生故障之前
,
允许一个不确定的结构进行应力重分布。
延性也增强了的能量吸收特性的结构
,
这就
是极为重要的
抗震设计。
2
、
3
、
2 types
of steel
钢的类型
Structural
steels
used
for
construction
purpose
are
generally
grouped
into
several
major
classifications
、
用于建筑用途的结构钢一般分为几个主要的分类。
Carbon
steels:
in
addition
to
iron,
the
main
ingredients
of
this
category
of
steels
are
carbon(maximum
content=0
、
22%) and
manganese, with a small amount of silicon and
copper, the most
commonly used
structural carbon steel is Q235, which is
extremely ductile and is suitable for both
bolting and
welding
、
碳钢
:
除铁
,
这类钢的主要成
分就是碳
(
最大含量
=0
、
22
％
)
与锰
,
用少量的硅与铜
,
最常用的碳素结构钢
Q235
的就是
,
这就是非常延展性
,
适合螺栓与焊接。
High
strength
low
alloy
steels;
these
steels
possess
enhances
strength
as
a
result
of
the
presence
of
one
or
more
alloying
agents
such
as
chromium,
copper,
nickel,
silicon,
vanadium,
and
other
in
addition
to
the
basic
elements
of
iron,
carbon,
and
manganese
、
Normally,
the
total
quantity
of
all
the
alloying
elements
is
bellow
5%
of
the
total
composition
、
These
steels
generally
have
higher
corrosion-resistant
capability than carbon
steels
、
Q345,Q390 and Q420
are all high strength low alloy
steels
、
低合金高强度钢
,
这些钢具有增强强度剂
,
如铜
,
镍
,
< br>铬
,
硅
,
钒
,
除了铁
,
碳的基本要素与其她一种或多种合金的
存在下
,
作为结果
,
与锰。通常情况下
,
所有的合金元素的总数量
,
就是波
纹管的总组合物的
5
％。这些钢材通常具
有较高的耐腐蚀能力比碳钢。
Q345,Q390
与
Q420
低合金高强度钢。
Quenched and tempered alloy steels; the
quantities of alloying elements used in these
steels are
in
excess
of
those
used
in
carbon
and
low
alloy
steels
、
In
addition,
they
are
heat
treated
by
quenching
and
tempering to enhance their
strengths
、
These steels do
not exhibit well-defined yield
points
、
These
steels, despite their enhanced strength, have
reduced ductility
、
淬火与回火合金钢
,
用于这些钢的合金元素的数量超出那些
用于碳钢与低合金钢。此外
,
她们通过淬火与回火
的热处理
,
以提高她们的长处。
这些钢没有表现出良好定义的屈服点。
这些钢材
,
尽管她们增强实力
,
降低延展性。
2
、
3
< br>、
3 design considerations
设计考虑
Special
problems occur with steel work and good practice
must be followed to ensure satisfactory
performance in
service
、
特殊问题的发生<
/p>
,
必须遵循与钢的工作与良好做法
,
以确保安全因素令人满意。
1
、
Fatigue
耐久
Fatigue
failure
can
occur
in
members
subjected
to
fluctuating
loads
such
as
crane
girders
or
bridge
structures
、
Failure occurs through initiation and propagation
of a crack that starts at a fault or
structural discontinuity and the
failure load may be well below its static
value
、
耐久失效可能发生波动
负荷
,
如吊车梁桥结构构件。
故障发生
时通过一条缝
,
开始出现故障或结构不连续
,
破坏
荷载可能会远远低于其静态价值的萌生与扩展。
Welded
connections
have
the
greatest
effect
on
the
fatigue
strength
of
steel
structures
、
Tests
show
that bull welds give
the best performance in service while continuous
fillet welds are much superior
to
intermittent fillet welds
、
<
/p>
焊接连接有钢结构的疲劳强度的影响最大。
测试结果表明
,
防撞焊缝给表现最好的服务
,
同时连续角焊缝远优于
断续角焊缝。
The maximum stress level at the weld
toe is known as the hot spot
stress
、
The fatigue life of
a
welded
structure
can
be
predicted
based
on
the
hot
spot
stress
range
at
the
welded
region
、
Alternatively,
fracture
mechanics
approach
can
also
be
used
to
calculate
the
remaining
life
of
welded
structures
with
initial
crack
、
Under
cyclic
service
loading,
crack
always
initiates
at
the
areas
of
stress
concentration
、
被称为热点应力的最大应力水平上面的焊趾。
焊接结构的耐久寿命可
以预测基于热点应力在焊接区域的范围。
另外
,
断裂力学的方法也可以被用于计算焊接结构的剩余寿命与初始裂纹。
根据循环服
务的负担
,
裂纹总就是发起
的应力集中
区域。
2
、
brittle fracture
脆性断裂
Structural
steel
is
ductile
at
temperatures
above
10
but
it
becomes
more
brittle
as
the
temperature
falls
、
And
fracture can occur at low stresses below
0
、
The charpy impact test is
used to determine
the resistance of
steel to brittle fracture
、
In this test, a small specimen is broken by a
hammer
《土木工程专业英语》陈瑛
_
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_
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and the energy or toughness to cause
failure at a given test temperature is
measured
、
在
10
以上的温度下结构钢的韧性
,
< br>但它变得更脆
,
随着温度的下降。骨折可以发生在低应力
低于
0
。的夏比冲
击试验就是用来确定
钢的耐脆性断裂。在该试验中
,
一个小的试样用锤打破的能量或
韧性造成的故障在给定的试
验温度的测量。
By
careful
selection
of
steel
grade
with
adequate
impact
toughness
and
good
detailing,
the
likelihood
of
brittle
fracture
can
be
reduced
、
Thin
plates
are
more
fracture
resistance
than
thick
ones
、
Abrupt
changes of section and stress
concentration should be
avoided
、
Fillet welds should
not be laid down
across tension flanges
and intermittent welding should not be
used
、
精心挑选的钢级有足够的
冲击韧性与良好的细节
,
可以减少脆性断裂的可能性。
薄板断裂性比厚的。
应避免突
然变化的部分与应
力集中。角焊缝不应放下跨张力法兰与间断焊接不应使用。
3
、
Fire
protection
消防
Steel structures without fire
protection may suffer serious damage or even
collapse in a fire
catastrophe
、
This
is because the mechanical properties of steel
deteriorate by heat during fires,
and
the yield strength of conventional
steel at
600 is
less
than
0
、
3
of
the specified yield
strength
at room
temperature
、
Fire protection
can be provided by encasing the member in
concrete, fire board
or cementitious
fiber materials
、
The main
types of fire protection for columns and beams are
shown
in figure
2
、
7
、
more recently, intumescent paint is being used
especially for exposed
steelwork
、
没有防火的钢
结构在火灾灾难可能会严重受损甚至崩溃。
这就是因为钢的机械性能恶化
,
通过热在火灾过程中
,
与传
统的钢的屈服强度在
600
指定的在室温下的屈服强度小于
0
、
3
。可以提供
防火保护套部件
,
在混凝土中
,
防
火板或水泥纤维材料。
立柱与横梁的防火保
护的主要类型
,
如图
2
、
7
所示。
最近
,
正在使用的膨胀型涂料
,
尤其就
是对裸露的钢结构。
4
、
Corrosion
protection
腐蚀防护
Atmospheric corrosion occurs when steel
is exposed to a continuous supply of water and
oxygen
、
The
rate
of
corrosion
can
be
reduced
if
metallic
coating
or
painting
is
used
、
Other
methods
of
corrosion
protection are
sherardizing, concrete encasement and cathodic
protection
、
发生的大气
腐蚀钢暴露于水与氧的连续供应。
可以减小腐蚀的速度
,
如果使用金属涂层或涂漆。
渗锌防腐蚀保
护的
其她方法
,
具体的装箱与阴极保护。
Questions
1
、
how
to
describe
the
mechanical
properties,
l
、
e
、
,
strength,
stiffness,
toughness
and
ductility,
from a typical
stress-strain curve of steel material measured
from uniaxial coupon test?
怎么形容的力学性能
,L
、
E
、
,
强度
,
刚度
,
韧性与延展性
,
从
一个典型的钢材料应力
-
应变曲线从实验中测量的？
2
、
what
are
the
general
measures
in
practical
engineering
for
fire
protection
and
corrosion
protection
for steel members?
在实际工程中的钢构件防火与防腐蚀保护的一般措施就是什么？
答案后两段
2.4
Structural
Steel Shapes
型钢
Steel sections used for construction
are available in a variety of shapes and
sizes
、
In general,
there are three procedures by which
steel shapes can be formed: hot-rolled, cold-
formed, and welded
、
< br>用于建筑型材可在各种形状与大小。一般来说
,
有钢材的
形状也可以形成有三个程序
:
热轧
,<
/p>
冷弯
,
焊接。
2
、
4
、
1 rolled and formed sections
推出
,
冷弯型钢
Rolled and formed sections are produced
in steel mills from steel blooms, beam blanks or
coils by
passing
them
through
a
series
of
rollers
、
Rolled
and
formed
sections
have
the
following
shapes,
which
are also shown in
figure 2
、
8;
钢厂从钢华
,
梁坯或线圈通过她们通过一系列的辊轧制
,
冷弯型钢生产。轧制与形成部分具有以下的形状
,
这也
示于图
2
、
8;
I-section: these are very
efficient sections for resisting bending moment
about the major axis
、
I
部分
:
这部分就是非常有
效的抵抗弯矩的长轴。
H-section: these
are sections produced primarily to resist axial
load with a high radius of gyration
about the minor axis to prevent
buckling in that plane
、
H-
部分
:
这部分主
要生产具有高回转半径的短轴防止屈曲
,
平面抵抗轴向载荷。<
/p>
Channels: these are used for
beams, bracing members, truss members and in
compound members
、
通道
:
用于梁
,
支撑构件
,
桁架构件与复合成员。
Equal and unequal angles: these are
used for bracing members, truss members, purlins
and sheeting
rails
、