Hidden & neat-looking splice connections for SSHS

[bugbus]

I'm working on a pedestrian bridge concept design, which will be a truss comprising square SSHS sections. The truss will need to be transported in at least a few pieces, and spliced together on site.

I recently saw the following example, but I'm not sure what is really going on internally. My best guess is something like below:

A few questions I have:

*Are there any alternative/better solutions for this?
*I would have some concerns about water getting into the connection. Would this need some kind of gasket or seal?
*How would that detail affect the overall buckling behaviour of the truss (if at all)?
*Would you have a preference on HolloBolts (or similar) vs standard through bolts? I believe the HolloBolts would have some clamping effect between the inner and outer SSHS members which might limit slip.
*Any issues with assembly? I note that all 3 members (i.e. the 2 chords and the diagonal) might be hard to install since they are not all parallel. I suppose there would need to be some wiggle room between the spigot pieces and the outer SSHS to allow this to be 'banged' into place?

Appreciate any tips or advice!

 

[TOLstryk]

I've used the Shuriken splice system from Atlas Tube before.

https://www.atlastube.com/products/shuriken/

 

[milkshakelake]

*I would have some concerns about water getting into the connection. Would this need some kind of gasket or seal?

This is a big problem with HSS members in general. If you're not welding it to make it fully closed, I wouldn't just rely on gaskets or seals. I'd add weep holes to the bottom of the beams, regularly spaced. It's not ideal, but it's better than nothing.

Personally, I wouldn't use Hollo Bolts and instead weld the HSS together, because of the water issue. One would slot into another using a dowel type of connection, or use an erection plate (or a few of them). I forgot to draw it, but option 2 would have weld after it's been slotted.

If you do use the bolt idea, the main issue would be moment transfer. You'd need a bunch of bolts to make it a moment connection to have continuity of the beams. I think the Shuriken Splice is a good idea if you make it a longer one, like in some of the examples. They say it's been used for pedestrian bridges, so I'd think that they solved the water issue by using weep holes or something.