"SSLH" on a single plate connection 1

[Veer007]

Hello Guys, I have a suspicion, As I saw in the contract dwg, is it mandatory to provide "SSLH" on a single plate connection?

Indicated as "short slotted holes shall be used"

Thanks in advance!!

 

[271828]

They are typically used, but typically not mandatory.

If the EOR indicated to use them then they are mandatory because of that.

 

[Veer007]

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Thanks in advance!!

 

[JoelTXCive]

This ties in to the OP question...

Are the short slots on the connecting plate; or on the beam end?

 

[271828]

In all cases I've seen, the slots are in the plate.

Unrelated to whether they're in the plate or beam: The only "gotcha" that I've seen is when these slots are at a collector or braced frame beam, and the connection is not slip-critical. The detailer throws slots in by default, so someone needs to clearly indicate any axial loads in the beam.

 

[RPMG]

If the contract drawing says, "short slotted hoes shall be used", then horizontal short slots should be placed on the connector plate, and standard holes should be placed on the beam end. The logic may not be 100% correct, but that is standard operating procedure.

If standard holes were provided in the connector plates when short slots were specified, that is a field fit-up issue, not a structural issue. If the erector can make it work, then it's fine.

 

[ProgrammingPE]

If standard holes were provided in the connector plates when short slots were specified, that is a field fit-up issue, not a structural issue. If the erector can make it work, then it's fine.

Standard holes must be checked for a larger eccentricity than short-slotted holes per the Steel Construction Manual, Table 10-9, when there's 6 to 12 bolts. They also require a thinner plate or beam web to meet the ductility check, regardless of the number of bolts, so it is possible that using standard holes will be a structural issue too.

Structural Engineering Software:

http://www.structuralcentral.com

Structural Engineering Videos:

http://www.youtube.com/structuralcentral

 

[RPMG]

ProgrammingPE, you're absolutely correct. I have a bad habit of over-generalizing, and one of my recent replies about seismic design was misinterpreted. I told myself that I would do better, and then I gave advice here that may be "probably correct". You make a great note and criticism. Absolutely, do the design checks and follow the procedures.

 

[Veer007]

Guys, thanks for the info. received so far, Yes, I have to provide SSL in plate not beam, refer to below snap for table 10-9 suggest to use min plate thick when bolt numbers lie between 6 to 12, From all these comments, we can provide either STD or SSLT holes depend on bolt number,dia and eccentricity, right?

Thanks in advance!!

 

[271828]

Please clarify the question. Table 10-9 supports standard and short slots. But if the EOR said slots, then slots are mandatory.

 

[Veer007]

Yes, I know I have to provide SSL for this one as EOR stated, But I am asking generally, is this mandatory? or is it still good to provide SSL rather than STD?

Thanks in advance!!

 

[271828]

To my knowledge, the reason for using short slots is nearly universally ease of erection.

Table 10-9 provides some advantages for short slots, but I don't think that's why slots are typically chosen.

Fabricators and erectors don't like standard holes in the plate and beam.

When the beam has axial load, standard holes might be needed in both. When I've seen this happen, the fabricator pushed to have some other kind of connection at the other end of the beam to provide some tolerance for fit-up.

 

[RPMG]

For typical infill beam end connections that are simply supported with no axial transfer forces, it is best practice for the detailer to specify short-slotted holes in the interest of the erector. However, it is not mandatory for the detailer to assume short-slotted holes.

If short-slotted holes were required, which is unlikely, then the EOR or delegated connection designer has the obligation to specify them.

It is much more common for STD holes to be required for axial transfer forces and for the EOR to miss that, especially in open framing with bracing.