Double shear plate as a column beam connection

[Fernando Lopez]

Is the double-plate shear connection used as a connection? Do you think this is a a possible solution in practice? What about its design? All your answers will be appreciated. Thanks

 

[Flotsam7018]

As in a double shear tab connection? If so, this could work if you need the extra shear plane for the bolts, not seeing any other benefit. This connection is more difficult to erect so I would generally avoid unless the condition is very unique.

 

[cliff234]

You are probably going to have tolerance problems accurately locating the double plate so that the beam web can slide between the double plates with a negligible gap between the plates. Likewise single plate shear connections require a weld on both sides of the plates. You can't get a weld on both sides of both plates. Accordingly one of the plates will require a CJP weld which will add significant cost. What kind of shear strength are you looking to develop that you think you would need a double plate? Why not just use A490 bolts, or larger diameter bolts, or a thicker plate, or 50ksi plate material. What is the governing limit state that's giving you a problem?

 

[Eng16080]

Not sure this makes sense. Certainly, I've never seen this type of connection. In cases where a single angle doesn't work, it's common to use a double angle connection instead.

 

[Fernando Lopez]

You are probably going to have tolerance problems accurately locating the double plate so that the beam web can slide between the double plates with a negligible gap between the plates. Likewise single plate shear connections require a weld on both sides of the plates. You can't get a weld on both sides of both plates. Accordingly one of the plates will require a CJP weld which will add significant cost. What kind of shear strength are you looking to develop that you think you would need a double plate? Why not just use A490 bolts, or larger diameter bolts, or a thicker plate, or 50ksi plate material. What is the governing limit state that's giving you a problem?

Thank you for the answer. I do not have a specific problem to solve. I was just wondering if the double shear plate is a good solution in any case. From the answers I am receiving I am confirming that this connection is not recommended.

 

[human909]

Thank you for the answer. I do not have a specific problem to solve. I was just wondering if the double shear plate is a good solution in any case. From the answers I am receiving I am confirming that this connection is not recommended.

Double plates can make sense when there are very high axial loads, as a single plate can have problematic eccentricity. But in which case it isn't really a 'shear' plate. I occasionally use these for hollow section struts. But generally prefer a thick single plate to compensate for the eccentricity.

Also remember that you cant fillet weld both sides of both shear plates if you are doing a double shear plate connection. so you end up with half the weld and the weld being eccentric.

And as others have said if you really need the shear capacity double angles are great.

 

[DrZoidberWoop]

From recent memory, the only time I've used double shear plates was beam-to-BU 24x36x4" box columns @ vertical bracing w/ very heavy loads. They're a pain to fabricate because weld access is restricted on the 2nd plate and a CJP (w/ backing bar) is required. Very rarely used.

 

[Eng16080]

Another potential problem with the double shear plate is that it might not provide adequate ductility to meet the classification of a simple shear connection per AISC Table 10-1. In that case, the structural model (and member design) would need to account for moment being transferred at the connection. I think it might be ok (as a simple shear connection) if the connected plates and beam web thicknesses aren't excessive, although if the plate thicknesses are limited, that might defeat the purpose of using the double plate.