Type of Joints in portal frame

AI Thread Summary
In portal frame construction, the beam to column connection must be rigidly fixed, while the column to foundation connection can be either fixed or pinned. If the column base is pinned, the frame is stable in 2D but requires longitudinal bracing for 3D stability. Alternative frame designs exist where the beam is pinned to the column, but these are not classified as portal frames and are generally weaker. The discussion also touched on the flexibility of joints between gluelam beams and reinforced concrete columns, suggesting that a new thread may be more appropriate for that topic. Overall, the importance of fixed connections in portal frames is emphasized for structural integrity.
kitzlongg
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Homework Statement
What's the type of connection at beam to column connection
Relevant Equations
Pinned or fixed?
I was told that for building portal frame, the beam to column connection must be rigid , which means, it has to be fixed , while the column to foundation connection can be either fixed or pinned, am I right ? I couldn't find anything about this online . Pls help
 
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Yes , correct on both counts. The beam to column connection is fixed, whereas the column base support can be fixed or pinned. If pinned at the base, the frame is stable in 2D, but in 3D, the Frame must be longitudinally braced or guyed.

There are other frames where the beam is pinned to the column, but these frames must be fixed at the base where each column shares half of the transverse load, but these frames are not called ‘portal’ frames and are weaker and subject to large deflections unless they are cross braced.
 
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PhanthomJay said:
Yes , correct on both counts. The beam to column connection is fixed, whereas the column base support can be fixed or pinned. If pinned at the base, the frame is stable in 2D, but in 3D, the Frame must be longitudinally braced or guyed.

There are other frames where the beam is pinned to the column, but these frames must be fixed at the base where each column shares half of the transverse load, but these frames are not called ‘portal’ frames and are weaker and subject to large deflections unless they are cross braced.
So, for portal frame, the beam to column connection must be fixed , am i right ?
 
Yes, by strict definition of a portal frame.
 
[Mentor Note: a new discussion has been moved from this thread to the one listed below]

hellophysics said:
this is probably elementary: Is it possible to decide the flexibility of a joint between gluelam beam and reinforced concrete column? if I decide it to be flexible, can it still the corner frame take bending moments? or then it behaves as a simply supported beam?
Lnewqban said:
I recommend you to open a new one in order to get attention from a greater number of members, who can discuss details with you.
Perhaps, @berkeman can help with openining a new thread.

New thread spun off about the new question to the ME forum here: https://www.physicsforums.com/threa...of-an-avalanche-protection-structure.1062103/
 

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