Skywalk Separation

[xlren]

I am designing a skywalk between two buildings. This bridge is located in California, so it does suffer seismic loads. The expected displacement on the bridge could be as large as 5in in one direction. I had Caltran's bridge experience and tried to have a similar detail as pinned connection on one end and roller connection on the other end. Thus, the roller end needs to slide 2x5in=10in. It becomes unreasonalbe to have a slotted hole details on bearing plate.
I am wondering if there are common details for skywalk separation between buildings. Any help would be appreciated.

 

[SlideRuleEra]

Several years ago I designed an elevated structural steel walkway between two electric generating units. Each unit has significant, independent movement when in operation. Used teflon slide bearings at the free end of the span. Here is a link to a typical product

http://www.sepbearings.com/fluorogold.pdf

Over 15 years have come and gone, and the walkway/bearings are still in service. Perhaps a similar approach would work for your project.

http://www.SlideRuleEra.net

 

[xlren]

So, is that mean I can only weld the top and bottom plate separately? I am wondering if there is vibration problem caused by uplift seimic force while no anchrage is provided in the vertical direction.

Also, my roller end only rolls on the longitudinal direction. I am hoping to fix the transverse direction in order to transfer half of the seismic load. However, a 10" slotted hole would be needed for each anchorage.

 

[JAE]

xlren:

I think that the thumbnail drawings that are in the link that SlideRuleEra offered give you a starting point.

Generally, you can design almost any kind of expansion connection with these plates - I would call their technical representatives and they can, I'm sure, offer you some advice.

A few ideas from my head:

1. The top plate should always be longer and larger than the bottom to avoid dust and debris from collecting on the lower plate and gouging the teflon when it does slide.

2. A neoprene or elastomeric bearing should be used under the bottom plate to allow for rotation without gouging the teflon surfaces.

3. A long slot can be used in a custom length set of plates to allow for your movement.

4. Vertical seismic can be handled, I think, with through-bolts that vertically tie the upper and lower elements together - but not tightened to the extent that they interfere with the horizontal sliding.

5. Lateral forces (wind and seismic) can be handled with seperate key plates on either side of your beam. These "stops" would allow longitudinal sliding but not lateral, transferring the forces down into the supporting structure. They could even be faced with teflon as well to ensure good longitudinal sliding without binding. They also may need to be stiffened with plates as the height of the teflon arrangement might require them.