Field Issue During Steel Erection

[SteelPE]

I received a call this morning from a site this morning in regards to a building that is currently in the erection phase. The building is a warehouse utilizing open-web steel joists and joist girders with wide flange columns and bolts cast into concrete (4-3/4" dia ASTM F1554 Gr 36 (edited from 46) bolts in a 5" ga pattern). The detail we are using requires the use of a leveling plate an grout in the final configuration.

Due to cold temperatures, the GC is saying that they were not able to place the grout under the columns prior to steel erection, so they elected to use leveling nuts (which I just found out are only 1/2 the thickness of regular nuts... at least that is what I have been told). When the GC left the project last week everything was fine, then storms came in and not they have a group of columns that are no longer plumb (saying that they are not leaning considerably at the top (I don't recall if they said 3 feet or 3 inches).

The GC is saying that something stripped under the base plate (bolts or nuts). It sounds to me like the erector didn't brace the building properly (We went around about this a few times before I got off that ride as the GC insisted that everything was braced correctly). In the end, there is damage somewhere and I am not exactly sure where.

Two questions:

Has anyone run into this issue before (leveling nuts stripping)?
How do you fix the issue?

I am thinking they will need to plumb the building again and then the will need to install new post-installed bolts (not going to be easy). However, I am not sure if we should be having them do additional work.

 

[Aesur]

We typically call for 1.5 +- grout, never really through about the reasons until now. There are shoring engineers out there, most contractors reach out to those experts when they need engineered shoring in the US market. For the reasons mentioned already, I agree that shoring is contractor means and methods. @SteelPE - take a look at 1708 and 1709 of IBC 2018 for load testing guidance.

 

[ldeem]

On grout spacing I usually go 1.5" to allow room for reduced grouting height without having to switch from cementous grout to epoxy. I's been awhile since I looked into the details but I believe around 3/4" gap you have to use an epoxy grout.

I recently had some pull testing done to verify strength on unknown embedment anchors used for a jib crane base. The system the test firm used involved running a rod through a hollow hydraulic cylinder. Looking at your base plates I don't know if there would be room to do a pull test. In my case I ended up designing a small test fixture to get their cylinder to work with the existing condition.

 

[dik]

Aren't you supposed to use a roof rack?

-----*****-----
So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates

-Dik

 

[dvd]

Attached is Five Star grout product/application summary for both cementitious and epoxy grouts, other suppliers have similar selection guides.

 

[CrabbyT]

I worked on a project a while back that involved setting a vertical pressure vessel on a circular pad. The pad was connected to a large mat foundation. On the drawings, we noted that the pad should be 10" above the slab. The problem was, the slab was sloped, and the pad was very large in diameter. Long story short, the top of the pad ended up being sloped the same as the slab.

Edit:
And it was a lesson well-learned. Don't dimension things off a sloped surface, especially if it's sloped but looks flat on paper. I should've called out the T.O. Pad Elevation. Anyway...

Wouldn't have been an issue, but when they set the tank, they cut off the tops of anchors with a grinder. Lucky, there was a little bit of wiggle room between the edges of the anchor bolts and the holes in the base plates. They were able to pick it with a crane and hard shim it with stainless shims. We would've spec'd epoxy grout, but the gap was way too thin on some of the plates (like... 1/16").

You might advise the contractor that if they're unable to grout due to weather, they should hard shim columns in the future with plate.

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Did someone smash that car with a tree branch?