Spigot to Standard Connection- Scaffolding

[MarkR16]

Hi all,

I'm try to model a spigot to standard connection.
What I would like to end up with is a function which describes the moment rotation curve of the connection.

What I have so far:

The initial gap, Which I calculate with theata = atan (di-do)/length (EN 12811-1)

The ultimate bending moment as the weakest of the two components (spigot/standard). Mu,Rd= fu*Wpl (Eurocode 9)

Finally the rotational stiffness of the connection is the combination of both components in series. ktot = (GJ1/L)+(GJ2/L) (Wikipedia)

I think my approach is right but I am unsure. Any advice on how to solve this problem would be much appreciated.

Quick Examples below

 

[RHTPE]

I'm not sure I can help with your challenge here. I sense that your "big picture" goal is to assemble an analytic model of a scaffolding tower.

There have been numerous full scale physical tests performed by the manufacturers of scaffolding/shoring equipment to develop empirical load tables for their products. The load tables developed generally have a safety factor of 2.5 or 3 or 4 applied to be consistent with OSHA and other industry criteria.

If you are successful in developing an analytically model, I strongly recommend that you do a careful comparison with the industries' load tables AND consider the following:
1. This equipment is intended to primarily resist gravity loads. Lateral loads are intended to be resisted by other means.
2. Lateral performance of a scaffold or shoring is dependent on direction (parallel to the frame or to the X-brace).
3. Given the nature of how this equipment is assembled, there is no means to resist uplift. Thus, all legs must be loaded in compression to remain within the realm of safe use.
4. Also, considering #3, the top of a scaffolding or shoring tower will exhibit substantial lateral movement before any of the legs reaches zero compressive load.

If this is an intellectual exercise, God bless you for wanting to get into it. I had attempted this many years ago in my career and abandoned the idea after realizing that the empirical results of the physical testing is far closer to reality than any computer model will provide.


Ralph
Structures Consulting
Northeast USA

 

[racookpe1978]

And it will be put together by the cheapest possible crew on a backshift with (likely) only the foreman using English. Using parts left in the scaffold yard for 12-18 months in the snow, rain, and water. 8<)

 

[RHTPE]

racooke1978 - you are so very generous with the time frame that this equipment would be exposed to the elements. I have seen decades old equipment (rental fleet) in the yard of a former employer. One of my major concerns is the effect of internal rust & corrosion of the tubular elements that comprise a shoring/scaffold frame. I tried to advocate for manufacture date-stamping and a rigid program of internal inspection at appropriate intervals. Management and bean-counters could not (yet) see any merit in that thought.

Ralph
Structures Consulting
Northeast USA