简支梁桥的计算

板的有效工作宽度
m1 b l l
m2
b
The problem is presented out 问题的提出： When the local load applied on the slab, how much width will participate carrying the load? 局部荷载作用，板在多大范围内参与受力。
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 单向板的例子
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t
b1
b
l0 l
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a1
a
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 1）单向板
桥梁工程
Load荷载计算 Analysis内力分析 Reinforcement配筋计算
Roadway, girder,transverse connection
桥面板、主梁、横隔板计算
结构设计原理 桥梁工程
Drawing绘制施工图
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Span 计算跨径? Load distribution荷载分布？ Width 板带宽度?
l0
l0
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3.2 Slab design for the roadway 行车道板计算 2. Distribution of the wheel on the roadway
t 1）多跨连续单向板 主梁和板之间的作用 两种极端情况 t h h
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4. Internal force computation of the roadway 行车道板的内力计算
a1 mxmax a
Location of the load荷载位置
b1 l
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
When multi-load applied near the mid-span area
b1
当多个荷载重叠作用于板跨中附 近时： a = a1+d+l/3 =a2 +2H+d+l/3
a d l0 l
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a1 l0 l
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a’
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 1）单向板 When loads applied near the supported edges 当荷载作用于靠近板支撑处时 ax = a’ +2x
Bent moment on the mid-section 跨中截面弯矩图
有效工作宽度的概念
y
a × mx max = ∫ mx dy = M
mxmax
M a= mx max
x a1 b1 l a
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mxmax
mx max
M P = ~ a a
因此，只需要将车轮荷载平分到有效工作宽度a（沿纵 向）和b1（沿横向）内，即可。
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 List of the slab width of participation 单向板有效工作宽度汇总 ①a = a 1+l/3 = a 2+2H+l/3 且≥ 2l/3 ② a’ = a 1+t = a +t且≥ l/3 ③ ax = a’ +2x
l
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a) c)
b)
d)
Hinge connection between the wings of the girder 主梁翼板铰接构造 a)、b)
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Rigid connection between the wings of the girder 主梁翼板刚接构造 c)、d)
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 1）单向板 When loads applied on the supported area 当荷载作 用于板支撑处时 a’ = a1+t =a2 +2H+t and ≥ l/3
板的有效工作宽度 2）Cantilever slab 悬臂板 悬臂板的有效工作宽度定义与简支 板同。
a × mx max = ∫ mx dy = M a= M mx max
mxmax b
mxmax is the maximum moment on the root
section of the cantilever 悬臂根部截面的最大弯矩
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 Conclusion: 数值计算结果表明，板的有效工 作宽度主要与三个因素有关： Condition of the support支撑条件 Load distribution荷载分布性质
车轮荷载在板上的分布
a) P/2 P/2
b2 45 o H
A
The contacted surface between the tyres and the pavement
轮胎与桥面的接触面
b) Consideration of the pavement effect桥面铺装的影响 Longitudinal 纵向 a1=a2+2H Local distribution局部分布荷载
a=a1+2b’ H b1 45°
b’
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b’为荷载外边缘至悬臂跟部的距离
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a1
3.2 Slab design for the roadway 行车道板计算 4. Internal force computation of the roadway 行车道板的内力计算
3.2 Slab design for the roadway 行车道板计算
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3.2 Slab design for the roadway 行车道板计算 1.Types of connection detail 行车道板的类型
板的有效工作宽度 1）单向板 When single load applied near the mid-span area 当单个荷载作用于板跨中附近时 a = a1+l/3 =a2 +2H+l/3 and ≥ 2l/3
l ：computed span 板的计算跨径， for calculation of the moment计算弯矩时 l= l0+t and ≤ l0+b for the calculation of the shear计算剪力时 l= l0
BRIDGE ENGRG PART II
Part 2 RC & PC beam bridge
第二篇 钢筋混凝土和预应力混凝土梁式桥
Chapter 3
第三章 Analysis of simple supported beam bridge 简支梁桥的计算
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板的有效工作宽度 Application on the 单向板有效工作宽度的应用 如图所示：
P a ② q2 = P a′
a q1
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① q1 =
③ ② ①
③ qx
a’
q2
qx
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ax
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
a’
b1
x ax a1 l0 l
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
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3.2 Slab design for the roadway 行车道板计算
1. Structural Models of the roadway 行车道板的计算简图
a) Simple supported slab单向板 b) Cantilever with hinge铰接悬臂板 c) Cantilever 悬臂板 l
H b1 a2 a1
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Transverse 横向 b1=b2+2H
p=
P 2a1b1
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
l0
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3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 2） Cantilever slab 悬臂板 悬臂板的有效工作宽度接近 于2倍悬臂长度 a = a1+2b’
③ ② ①
a’
ax
l0
a
3.2 Slab design for the roadway 行车道板计算 3. Slab width participated for the load carrying
板的有效工作宽度 The application of the slab width of participation 单向板有效工作宽度的应用 车轮荷载作用下，有效工作宽度内的板将共同工作， 并承受相同大小的内力（弯矩），根据有效工作宽度 的定义，有：
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Chapter 3 Analysis of simple supported beam bridge 第三章 简支梁桥的计算 3.1 Review on the design procedure 设计过程回顾
简支装配式RC、PC梁桥的设计
Dimension 拟定尺寸