one direction unrestrained move bolted connection 2

[fcu45]

Hi

For elevated walkway steel structure supporting column top connection. I want to have unrestrained one direction move bolted connection to allow for thermal and deflection caused expansion and contraction to act as expansion joint.

Using base plate with slot bolt connection should suit my need?
Is there some arrangements to allow for directional move? As tightening the bolts will cause such movement to still cause friction with washer and base plate.

Thanks

 

[bigmig]

I can tell you from experience that slotting exterior bridge connections ends like this: years of rust and dirt basically locking things up. You can count on it not sliding eventually. I have seen sliding connections stop sliding, and structure start moving out of plumb (pilaster on a bridge).

Look into the slide pads. Basically fixed on one end of your bridge and 'sliding' on the other.

 

[hokie66]

When you say the walkway is supporting the top of the column, I take it to mean the "column" is actually a vertical wind beam. If that is the case, slotted connections can work, as the load is not always there. The movement connection would be at the top of the wind beam, not at the base plate. Otherwise, I agree with bigmig.

 

[fcu45]

Thanks colleagues
Actually I mean the walkway is being supported by steel column in which I wanted to allow for one direction movement.

My qpproach is that I wanted to prevent "if possible" the tear of column top base plate in contact with the bolts the same fore thd bolts.

The supported spans from both sides of ghis column are 22 meters and 15 in the other side.

Do you agree on allowing for directional movement or not needed?

Any reference standard in this topic is highly appreciated too.

Best regards

 

[hokie66]

I still don't get your word picture. A sketch might help.

 

[fcu45]

Appology for

See the central column in attached picture.

Similar case im talking about. But 2 columns supporting the concerened section.

Regards

 

[fcu45]

http://upload.wikimedia.org/wikiped...or_Visual_Arts_-_geograph.org.uk_-_673768.jpg

 

[AELLC]

Why not provide a sliding bearing pad or rocker connection where the walkway connects to the buildings, instead of at the central column?

Especially because lateral on the walkway is not going to be such a problem if the walkway is essentially a continuous element going across the central column.

 

[AELLC]

Actually I meant slider only at one end, at one building.

 

[fcu45]

I thought of it but it is not single span till the buildings in both sides there are columns in between.

Regards

 

[AELLC]

Provide fixed connx at walkway beam to column and design column for eccentricity (see attached)?

Columns tilt or deflect in one direction but are fairly rigid in lateral direction. The angle of "tilt" is very small because of the ratio of longitudinal thermal movement to height of column.

 

[paddingtongreen]

This arrangement doesn't make sense to me. I would use a single pole and would put the slip joints at the buildings, preferably inside the doors to protect from weather and dirt. I would use: fluorogold slide bearings or equal, there are several guide arrangements of the type required.

I would probably try to pin the column top and bottom laterally and fix it in-line.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin

 

[fcu45]

Thanks for the inputs

Any reference in regards the need/or not to have the expansion joint? Especially In terms of thermal expansion/contraction.

In terms of deflection it is limited to 10 mm.

The elevated walkway will connect between 2 existing buildings; that is why I have placed in both ends additional columns as original design of both buildings didn't consider that addition of 200 kN. Although it may pass but didn't want to risk.

 

[hokie66]

You have three columns for vertical support. How is the walkway supported laterally?

 

[CELinOttawa]

I'm with Hokie on this one... What are you doing to support this in the perpendicular to run direction? I think you have a more serious lateral issue...

How wide and how tall will this walkway be?

 

[fcu45]

The columns are designed to carry the latteral loads.there will be roller supports at both ends of the walkway.

Height from ground is 5 meter. Length 45.
Exposure to wind is limited.

Regards

 

[paddingtongreen]

Roller supports would be provided by slide bearing guides over the end columns. You would not want rollers at the ends and slide bearings at the center. If you put the expansion joints at the center column, the architectural finish will also need one.

Michael.
"Science adjusts its views based on what's observed. Faith is the denial of observation so that belief can be preserved." ~ Tim Minchin