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请教诸位一个问题

请教诸位一个问题# CivilEngineering - 土木工程

a*l2008-06-18 07:06

1 楼

Beam to column connection
Shear only connection
Double angle on beam web.
Bolted on both beam web and column flange.
设计bolts只考虑剪力,因为梁翼板没有和柱焊接不能形成有效的力矩.
但是,通常我们说shear only,简支梁端的连接,基本上free of rotation.
考虑极端情况,角钢长度和梁深一样,根据设计可以只用两个bolt,上下各一个关于中性
轴对称, 如何free rotation? 如果不能自由转动,岂不是可以承担弯矩,可以承担多少
? 最大为梁腹板屈服?
LRFD设计验算Shear, Bearing, Block shear (shear rupture)中,哪一项包含了上述内
容?
我是不是想得太奇怪了.

n*b2008-06-18 07:06

2 楼

我从research角度说说吧，实际设计，我没做过，但是我对steel connection有过很深
的研究（呵呵，吹牛呢）。
beam-to-column connection，传递弯矩的主要分fully restrained and partially
restrained connection. 还有Reduced Beam Section (RBS)。你说的那个pin-
connection,到实际应用的时候，shear 传递是靠column web和 beam web之间的
friction. 这里所说的column web是指shear tab welded to the column flange.
Without welding between beam and column flanges, the moment can be
transfered by that two bolts when there is no relative displacement between
the shear tab and beam webs. However, those re

【在 a*******l 的大作中提到】

: Beam to column connection
: Shear only connection
: Double angle on beam web.
: Bolted on both beam web and column flange.
: 设计bolts只考虑剪力,因为梁翼板没有和柱焊接不能形成有效的力矩.
: 但是,通常我们说shear only,简支梁端的连接,基本上free of rotation.
: 考虑极端情况,角钢长度和梁深一样,根据设计可以只用两个bolt,上下各一个关于中性
: 轴对称, 如何free rotation? 如果不能自由转动,岂不是可以承担弯矩,可以承担多少
: ? 最大为梁腹板屈服?
: LRFD设计验算Shear, Bearing, Block shear (shear rupture)中,哪一项包含了上述内

a*l2008-06-18 07:06

3 楼

我知道你的意思. 是可以承受很小一部分的moment.
但是即使是极小一部分,rotation也会相当大.
这个rotation如何实现?

between
not

【在 n**********b 的大作中提到】

: 我从research角度说说吧，实际设计，我没做过，但是我对steel connection有过很深
: 的研究（呵呵，吹牛呢）。
: beam-to-column connection，传递弯矩的主要分fully restrained and partially
: restrained connection. 还有Reduced Beam Section (RBS)。你说的那个pin-
: connection,到实际应用的时候，shear 传递是靠column web和 beam web之间的
: friction. 这里所说的column web是指shear tab welded to the column flange.
: Without welding between beam and column flanges, the moment can be
: transfered by that two bolts when there is no relative displacement between
: the shear tab and beam webs. However, those re

n*b2008-06-18 07:06

4 楼

No.
The rotation is proportional to the moment and depends on the stiffnes of
that section. Normally without the displacement between shear tab and beam
web, the rotation is very tiny. When the moment is larger than the capacity
of that pin connection, the bolts or the shear tabs or the beam web might
fail. And it is a little complicated and depends on the beam section.
wheel (Would you hold still ? Please) 的大作中提到: 】

a*l2008-06-18 07:06

5 楼

I might not express it correctly.
shear only connection = pin end.
I will assume the column web and angle has infinite thickness. Then it's
very much like classical simply supported.
The rotation angle will just be a direct result of load P(or w) and span
length L my question is, in my case, two bolts at both top and bottm web,
where does the rotation go?
if we have to say there is moment transfer there, how much, and how do we
check it?
I must be crazy. :(

capacity

【在 n**********b 的大作中提到】

: No.
: The rotation is proportional to the moment and depends on the stiffnes of
: that section. Normally without the displacement between shear tab and beam
: web, the rotation is very tiny. When the moment is larger than the capacity
: of that pin connection, the bolts or the shear tabs or the beam web might
: fail. And it is a little complicated and depends on the beam section.
: wheel (Would you hold still ? Please) 的大作中提到: 】

n*b2008-06-18 07:06

6 楼

first, I would assume the angle is parallel to the column web and connected
to the shear tab with two bolts perpenticular to the web plan.
Another thing is the rotation can occur even in the welded beam-column
connection. That rotation may be an elastic deformation in the beam section.
I think the rotation you mentioned is like a pin rotation. Since the pin-
connection in your model can only provide very samll moment resistant, we
consider it as pin-connection for design purpose.
However, if you

【在 a*******l 的大作中提到】

: I might not express it correctly.
: shear only connection = pin end.
: I will assume the column web and angle has infinite thickness. Then it's
: very much like classical simply supported.
: The rotation angle will just be a direct result of load P(or w) and span
: length L my question is, in my case, two bolts at both top and bottm web,
: where does the rotation go?
: if we have to say there is moment transfer there, how much, and how do we
: check it?
: I must be crazy. :(

a*l2008-06-18 07:06

7 楼

My original question was how rotation was achieved on bolted bearing type
bolts.
Looks like the rotation was achieved with oversized hole for the bolts.
Elastic deformation will contribute if the hole size is too small.
Thanks man.

connected
section.
capacity

【在 n**********b 的大作中提到】

: first, I would assume the angle is parallel to the column web and connected
: to the shear tab with two bolts perpenticular to the web plan.
: Another thing is the rotation can occur even in the welded beam-column
: connection. That rotation may be an elastic deformation in the beam section.
: I think the rotation you mentioned is like a pin rotation. Since the pin-
: connection in your model can only provide very samll moment resistant, we
: consider it as pin-connection for design purpose.
: However, if you

z*i2008-06-18 07:06

8 楼

基本上hole都要比bolt要大一些，这个你看一下fabricator给你的图纸就知道了，不然
bolt根本装不上。有的时候还是slot hole。那个就大更多了。
也就是说，shear only的bolt connection本来就允许水平移动。上下两个bolt，可以
水平移动，自然就会产生rotation.
如果要设计moment connection，要把beam flange 给 connect到column上才能算是可
以传递moment的连接。