Spliced Column Connections - Question

[Hunter90]

Hello all,

I am new to this site and have A LOT of questions that run through my mind as an E.I.T.

1) A column that is segmented and bolted with end plates per column end (see picture 1 below), doesn't this develop a hinge condition? And, would this be considered Structurally Unstable? Or do we just treat this as a multi-span condition. Secondly, is a bolted connection as shown below considered a "spliced connection" or is a spliced connection involved welding?

Picture 1:

2) Similar to question 1, for a GERBER SYSTEM with an end beam picked up by a end column that is then picked up by the cantilever tip (see picture 2 below). How do you analyze this condition? A simple bolted connection would create a "pin type connection"? Or do we need to have a moment connection to transfer the moment to the end columns?

Picture 2:

There are many many more questions running through my head, but I will only ask this for now. Any insight will be much appreciated.

Thank you,
Hunter

 

[EngDM]

1) you can develop this connection to transfer moment, looking at the bolt bearing and prying action. Basically, can the bolts take the tension and is the plate rigid enough to not just yield under the moment load, and then of course welding the columns to their respective plates.
2) Assuming that there is a column past your breakline, you end up having a simply supported beam (the one on the left of your hinge) and a cantilever beam. Depending on the length of the cantilever vs the length of the span, you may or may not have uplift on that rightmost support. If there is no column to the right of your breakline, the column to the right of the hinge will be designed for moment.

The hinge is typically not designed to transfer moment, as utilizing cantilevers can reduce your overall depth of beam and save some weight since you are unloading the cantilever beam, and shortening the simply supported one. Take a look at the beam tables, you can observe this in action by looking at the cantilever graphs, and seeing the different load conditions impose positive and negative moments; these would superposition onto eachother.

Hopefully this helps!

 

[milkshakelake]

Moment connections are generally when you restrain the flanges from rotation. So in #2 when you have a shear connection, you don't have top and bottom plates to transfer moment, so the only moment being transferred is through the shear plate itself. All shear connections (like clip angles) have some moment resistance and can restrain rotation, but we idealize them as shear only / pin connections.