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Fabricator substituting standard holes with short-slotted 1

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Wburger14

Structural
Dec 22, 2009
4
Fabricator is asking for short-slotted holes where we spec'd standard holes. Steel member is a "typical" simple-span W-shaped beam with only gravity loads. Fabricator shows slots perpendicular to load (horizontal) as we'd like to see them. Connection is pretty standard stuff (from my vantage point) - designed as bearing with high strength bolts, threads included, finger-tight.

From a design/calc standpoint, are there any checks necessary to approve the short-slotted holes? My quick once-over of the code makes me think the fabricator's recommendation is OK. I'd like to approve the change as I know the short-slotted holes will help the erectors with fit-up.


Apologies as the Q may seem trite or simple but I'm an EIT with 2+ years of concrete design practice experience doing shops on my first steel design - just trying to save myself a bit of code-hunting.

happy.gif
2nd Q: Any other general shop drawing/CA/field inspection tips for a steel newbie?
 
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Just make sure he uses plate washers instead of the standard washers. OK from there.
 
What's the reason for finger tight?
To me that implies you are expecting some horizontal movement within the joint, and therefore slotted holes would be expected.
 
Forgive me, snug-tightened bolts are what we truly spec'd and is reflected as such on the shops. Freudian slip above (I've been trying to self-educate on the AISC bolt spec and other steel lit quite a bit recently).

The short-slotted holes are necessary from the erector's perspective because we have a few bays of supported slab being expanded into a confined, existing space. Apparently all the long-slotted holes we included didn't keep them happy enough.
 
Plate washers are not required for short slots.

What is the connection material? Single plate (shear tab) connections?

AISC 13th Ed allows for single plates with up to 3 1/2" eccentricity, with no consideration of eccentricity on the bolts (straight shear). SEE 13th ED p10-101

This applies to a single column of bolts only. For multiple columns eccentricity must be considered. And slip-critical bolts must be used with short slots.

This also assumes that the connection is not to a concrete embed. Single plates are "rigid" connection, therefore the embed must consider the moment, rather than shear only.
 
connectegr...agree plate washers not req'd. for short slots...many fabricators long slot the holes anyway when short slots intended.
 
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