Block Shear 1

[eit09]

I have a double angle veticle brace with one row of bolts connecting to a gusset plate. For block shear I use the formula from AISC 9th 0.3F_uA_v + 0.5F_uA_t.

In the case of 1 line a bolts I usually caclulate the available block shear strenght with A_t= 0. It has been braught to my attention that this is overly conservative and I need to acount for an A_t from the bolt to one edge of the gusset plate.

Is this correct, I should account for some A_t even though there is only one row of bolts? In all other calculations my A_t is the distance between the bolt rows.

 

[StrPE]

Yes, At should be considered from bolt line to the nearest free perpendicular edge of the gusset plate. In the case of a long edge distance, one that could not possibly govern, I have used At = 0, but multiplied Av x 2. This assumes a "plowing out" of the gusset plate, failing along two lines of shear.

 

[WillisV]

StrPE - that kind of failure is what the bearing and tearout limit states are for.

 

[connectegr]

Depending on your condition, the areas should be totals. The total shear cross-section and the total tension cross-section.

See attached

http://www.FerrellEngineering.com

 

[eit09]

Connectegr,

For the case of two rows of bolts you are correct, but the condition for a verticle double angle at 45 deg with a single row of bolts connecting to a gusset is the case in question.