The better simple connection for vibration? 1

[GalileoG]

I was told that clip angles are far superior to shear tabs when there are significant vibration in the structure, but I can't pin my head around why that may be. Perhaps someone here can clarify?

 

[GalileoG]

err I meant double clip shear connection by "clip angles"

 

[civilperson]

Who told you this attribute of double clip angles?

 

[csd72]

Maybe its due to lesser fatigue capacity of the welds and the fact that the bolts need to plough through the steel to nesure ductility.

 

[GalileoG]

csd72, can you please clarify on this point?

"bolts need to plough through the steel to nesure ductility."

I am not sure I fully understand that.

 

[csd72]

Look at the design philosophy on single plate shear connectors, the maximum thickness of the plate is limited to ensure that the rotational capacity at failure can be accommodated by yield of the plate.

On second thought, this is a failure criterion so probably doesnet effect vibration.

 

[271828]

"I was told that clip angles are far superior to shear tabs when there are significant vibration in the structure, but I can't pin my head around why that may be. Perhaps someone here can clarify?"

I don't believe there's any truth to this when it comes to floor vibration.

The UK SCI DG on floor vibration details the steps to use for FE modeling of structures to evaluate floor vibe. For vibration, shear connections should be treated as if they're fixed. There is insufficient movement due to walking to allow simple connections to rotate.

The other reason is that the natural modes usually act as if these conns are fixed. For example, a three equal span open-web steel joist footbridge will have exactly the same bending modes (frequencies and shapes) as a continuous beam with the same mass, length, and MOI.