Long slotted holes in extended shear plate connection

[Nitesh Sadashiva]

Hello all,

I have a condition of beam to column web extended shear plate connection. Since the column is existing, EOR want us to provide long slotted holes in extended shear plate for adjustment. AISC specifies SSL holes are permitted to use at extended shear plate connections. But there is no literature regarding the usage of long slotted holes. Is it permissible to use bearing bolts with long slotted holes in extended shear plate? In an extended shear plate, we are checking the bolt group for moment due to eccentricity by utilizing co-efficient "C" from AISC manual table 7-7. If we use long slots, how do we ensure bolts can carry moment? Because of the moment on bolt group, doesn't the bolts move in the slotted holes? Any ideas or thoughts on this?

 

[human909]

-In an extended shear plate you are not normally designing the connection to carry moment.

-Depending on your code you may need larger sized washers if you are using over sized holes or slots.

 

[DrZoidberWoop]

You can use long slotted holes for shear plate connections. AISC 360, J3.2(f) permits long slotted holes in "only one of the connected parts in a slip-critical or bearing-type conx." They can be used in either direction in a slip critical conx., but only perpendicular to the load direction in bearing connections.

You'll need to spec the proper washers to cover the LSL holes.

Occasionally, my company disregards this rule for shear plate connections to embeds. A pair of LSL holes typically provides enough slop to accommodate concrete construction tolerances. This is usually sent to the EOR for approval at the onset of a job.

 

[Nitesh Sadashiva]

@DrZoidberWoop: I agree with section J3.2(f) if bolts are concentric. But for the eccentric bolts, how can we justify the instantaneous rotation of the bolts with the presence of long slotted holes due to the eccentric loading?

 

[DrZoidberWoop]

I would justify it the same way we do with short slotted holes. If it bothers you, then design the connection as slip-critical and apply the appropriate limit state factor.