Pass Through Forces Steel Connections 1

[macan1]

Re: structural steel
In braced frames the connections should be designed for "pass through forces" shown on the drawing.
I am looking for definition of "pass through forces" and references about this.
Please suggest.
Thanks.

 

[Stress02]

Never heard of it.

 

[UcfSE]

Where did you get that phrase?

 

[FalsePrecision]

I am guessing that it is the horizontal component of the force pulling thru the beam-column-beam-connection. It varies depending on how many bays you are away from the braced bay (just a guess).

 

[macan1]

Pass through forces at connections are common in Canada.
It is happening at connections with braces.
We need to show these forces on the drawing for the steel detailers.
It has to do with horizontal forces (wind, seismic).

 

[VirtualEngineer]

Horizontal load has to be transfered into a braced frame somewhere.

A line of horizontal load, from a floor system for example, may be transfered back to one braced bay. As the load is transferred from beam to beam, the axial load is transferred though the connection. Usually axial tension is of most concern. The axial tension may increase the connection angles from 5/16 up to 3/8 or 7/16 due to prying action on the angles. Also the bolts need checked.

When I am reviewing shop drawings I always check to make sure the connection loads are fully developed. These pass thru loads must be included.

Another example of pass thru loads that can easily cause significant effects to the connection design occurs when two bays next to each other require clear spans at different levels. The full horizontal component of the brace load must be passed thru the common column.

William Thornton has done a lot of work on connection design and I recommend reviewing some of his papers available thru the AISC.

Best Regards to All

JPJ