member releases

[Vipin Satheesh]

I an trying to design a temporary working platform around a column.The platform size is 1.1 x 1.1 m.The working surface is a wooden deck.The members(CHS 76X6) overlap each other and are connected to column flange and each other with the help of clamps.I would like to know if there are any releases possible.The loads have been considered as per ASCE 37-02. The staad model is attached for review.Any kind of help would be appreciated.

 

[Vipin Satheesh]

The type of platform required and its connections are shown in the attache images.

 

[dik]

If secured to the column, then I would treat the channel members as cantilevers from the column and would treat the attachment of the channels at the column to resist all dead and live loading plus unbalanced live loading.

Dik

 

[TLHS]

I'm not going to open up the staad model, but I assume the channels are continuous past the edges of the columns, so the moment ends up as a pair of couple forces on either side of the column? The connection points would, then, effectively be pin supports.

I know there's testing behind what they're doing, but the fact that it looks like vertical load is being taken up by friction in the clamps scares me. I'm not sure I'd want to go up on that, when life safety is dependent on the QA/QC process of the contractor's clamp tensioning procedure.

 

[jayrod12]

Is CHS not circular hollow section?

If everything is clamp connected then my assumption would be pinned.

 

[Vipin Satheesh]

Thanks for the review but I am not inquiring about support.I have provided the support as pinned but since the continuous beams extending beyond column are also connected by clamps I would like to know whether providing releases of member is possible.I think releasing the members is not correct somehow.But since clamps are provided the connections cant be with moment I guess.Is the assumption correct. The section is circular hollow section(PIP 76x6).

 

[WARose]

Just looking at the picture.....I'm not 100% sure. The problem with any kind of clamp is: knowing what kind of clamping force we are talking about. That can make a big difference in fixity.

That being said, looking at your model, at the very least I would release the torsional fixity. (And maybe do an offset to better represent the fact the members are on top of each other.) Not 100% sure what to say about moment that could cause the pipe to slip out of the clamp......but you probably have fixity perpendicular to that since it probably can't force the clamp open in that direction.

Probably some type of diagonal(s) (back to the column; in plan view) would give you the stability you want.