High Elevation Walkway Connections 2

[shesanEIT]

I am working on a high elevation platform/walkway connecting two vessels. I am looking for examples, input, or advise on the best connections for the job.

For different elevation platforms I've seen stairs hinged at the top, then free at the bottom to allow for twist, sway, etc. however, the client wants some walkways at the same elevation.

I know slotted connections and over sized bolt holes can allow for movement, but for this project we are up 200 feet in the air, with some pretty good sway and deflection (and I have read about the failures with slotted connections).

I was also advised to rest the walkway beam on another member and leave a gap equal to the addition of the lateral movement in each vessel (and if over 1", provide a plate on top) and the metal on metal will allow movement. But what about vertical movement? Twisting? I need a connection that will allow and withstand all of it.

Thanks for any input!

 

[hokie66]

Don't depend on slotted connections. Sounds like an application for guided slide bearings on one end.

 

[shesanEIT]

Thanks @hokie66
Are you suggesting the other end be free to allow for twist and lifting? Guided slide bearings only allow for movement in one direction, correct?

 

[SlideRuleEra]

Some years ago, I designed a lengthy, level, elevated walkway between to two independent units at an electric generating station. During operation, movement / vibration of the two units is significant. One end of the platform is fixed (bolted) the other end rests on PTFE (Teflon) slide-plate bearings - as hokie66 mentioned. The plates support the platform and allow longitudinal movement and limited horizontal / vertical displacement. I put steel guides adjacent to the walkway beams to prevent these beams from sliding off the side of the Teflon plates or if any uplift occurred. Don't know if it is still in use, but I do know it provided 15+ years of satisfactory service.

Here is a link to info on this type slide-plate bearings: Link

http://www.SlideRuleEra.net

http://www.VacuumTubeEra.net

 

[hokie66]

SRE has it, with the PTFE bearings. You do have to provide restraint for uplift and transverse movement. That can be done by either providing the guides yourself, or purchasing proprietary bearings like these:

http://www.granor.com.au/products/structural-bearings/series-bgsu-up-lift-restraint

 

[shesanEIT]

Thanks very much for the details @SlideRuleEra. Seems like a simple solution!

 

[shesanEIT]

Aha, thank you @hokie66.

 

[BUGGAR]

We've done similar with the ptfe coated plates but used fabricated pins with restrainer plates in the slotted holes in lieu of bolts. I remember using 3 inch diameter pins on one walkway. The pins can be as big as you need and can be designed for uplift.