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Block shear - Failure plane including segment inclined to applied force in welded connection 3

CTJ6

Structural
Aug 26, 2015
3
0
0
CA
Hi,
The critical path in a block shear failure involves one or more planes of shear that run parallel to the line of applied force, and one plane of tension that runs perpendicular to the force. For bolted connections with staggered bolts, the segment inclined to the force between the bolt holes is calculated as An= wt + s^2/4g. But how to you treat a segment that is inclined to the force in a welded connection. The s^2/4g formula appears to be empirical and used for bolted connection but would it be reasonnable to use it in a welded connection to account for the inclined part that is both in tension and shear?
Tnaks,
 
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OP said:
The s^2/4g formula appears to be empirical and used for bolted connection but would it be reasonnable to use it in a welded connection to account for the inclined part that is both in tension and shear?

I vote yes. Two reasons:

1) Your rupture plane is the same with a welded setup and a bolted setup if I understand your situation correctly. So no difference there.

2) My understanding is that the empirical equation is meant to account for the interaction of shear and tension in ruptured material where the orientation of the rupture plan would be inclined relative to the load (but less than perpendicular to it).
 
My understanding is this equation is meant only as an adjustment for a section with holes. Basically you would take the gross width, deduct any holes and then add the quantity s^2/4g. It's meant to adjust for the overly conservative hole deduction when you have a staggered hole layout. See Section B4-3b of AISC 360.

I did a bunch of research on this awhile ago, which I'm now partially forgetting, but the equation is empirical and originated from a paper in 1922 (see attached).

I can sort of see your point, though, for non-bolted connections as the equation is based on an inclined failure plane.
 
 https://files.engineering.com/getfile.aspx?folder=104764fd-d6e0-4ca8-91e1-8d5d2860fa67&file=Rules_for_Rivet-Hole_Deductions_in_Tension_Members_-_1922.pdf
Eng16080 said:
I can sort of see your point, though, for non-bolted connections as the equation is based on an inclined failure plane.

No, you have the right of this. I retract my previous response as being incorrect. I read something on this where the wording was a bit wonky and I wound up misinterpreting it.

 
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