Would you pour wet concrete against an exposed steel beam? 4

[Greenalleycat]

Hopefully my image upload works...

I turned up to inspect a site today and noticed a steel beam floating in space
Turns out the blockies got the column height wrong and need to add an extra half block under this beam
They were planning to do this with the beam in-situ; it cannot be readily removed now as bolts have been epoxied in at each end that lock it in place unless they are drilled out

I'm not happy with this on two counts
1) No guarantee of positive seating of the beam which is structurally required as the bolts weren't designed for permanent loads on them, they are effectively just stability bolts
2) I'm not happy with wet concrete going against the beam coating... in my head this is just asking to create a corrosion issue as the beam will be sitting there exposed afterwards

I'm confident in my position on #1 but I'm not sure about the validity of #2 - is this a fair concern?

 

[dik]

I'd like to see how others react to this... I wouldn't be overly concerned...

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

-Dik

 

[Tomfh]

Where is the concrete going? Wouldn't you just grout it up?

 

[jerseyshore]

For #1, I feel like there are enough ways to get that beam tight to the bearing plate. Just keep banging shims in until it's tight is something all contractors love to do.

For #2, I wouldn't be very concerned either. Wet concrete is around steel all the time.

 

[HTURKAK]

I would prefer to insert a Channel or Box section to the space then grout up to bottom of steel beam..









Don't underestimate a nail. A nail saves a horseshoe, a horseshoe saves a horse, a horse saves a commander, a commander saves an army, an army saves a whole country.. GENGHIS KHAN

 

[TLHS]

I'd be annoyed that this was in my building, but if I saw a grout install of that depth on an existing structure it isn't something that would significantly worry me if there weren't appreciable lateral load on it. The only real issue with a grout pour that deep would be shear transfer, and it sounds like this is basically vertical loads if those bolts are just for stability. I'd probably call up Sika and see if they have a good product for this. Deep grout pours can sometimes require a larger aggregate size to hold things together.

There might be an aesthetic issue with a deep grout pour, though. You don't have space for a nice chamfer, so you'd likely form it with vertical sides. That is more likely to crack in the future.

If you don't like the depth of pour, you can likely fabricate a plate and box section weldement with some slots in it to fit around the bolts, weld or wedge that in place and then grout under that for the final bearing surface. There's also likely a way to just bear on the few inches of the block column past the bolts, to avoid dealing with those. With a field weld maybe you don't need to grout at all if you're clever.

I'm unclear what the potential issue is with concrete exposure.

 

[Lomarandil]

Agreed with the lack of concern about concrete.. we pour concrete decks over uncoated steel to create composite beams all the time.

The harder part of placing it under the beam will be ensurinng good fill and consolidation (concrete or grout). Probably will need an oversized pocket for that reason.

 

[XR250]

I would build a form and use pancake batter consistency grout.

 

[bones206]

They could put in a cut block to leave a ~1" gap below the beam (U-shaped to fit around the anchors), grout it solid, then come back and dry-pack the remaining space up to the beam bearing. This fix would be indistinguishable from the original design, I think.

The beam was always going to be in contact with concrete/grout of some form, so corrosion risk would be unaffected.

 

[EngineeringEric]

I'd say to use a drypack under this, one that can do your height of +4". We dry pack under columns all the time.

Side note: i'd be concerned with how the block was placed as it doesn't appear to be locked to the perpendicular wall like a pilaster. it looks like a single cell column that appears to have already failed at the adjacent pilaster (note the gap at the top)?

 

[jerseyshore]

Good eye Eric. What are those, 8x8 solid blocks? What's holding that pilaster up?

 

[XR250]

Also, why it the end plate bolted to the face of the CMU? Looks like the beam further down does not even have a pilaster - just and end plate connection.

 

[GeorgeTheCivilEngineer]

1) Concrete to 25 - 50mm below beam. Pour non-shrink grout for the last bit.

2) Wouldn't be concerned regarding corrosion. Once the concrete/grout is cured this is a non-issue.

 

[dik]

Have to check... some grouts have a maximum thickness...

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

-Dik

 

[jerseyshore]

Definitely strange looking setup. Not anything I would see in this area. Maybe this is more common down there.

 

[hokie66]

I don't think it is common 'down there' either.

 

[jerseyshore]

In this one photo we have steel beams supported by only bolts and also steel columns and 8x8 solid pilasters that may or may not be built into the wall, some with beams bearing and some without.

I figured it out, this is one of those mockups they have at the masonry institute showing all the different conditions.

 

[Greenalleycat]

Yes this is a common form of construction down here. It's also an insurance replacement for an existing house so the starting point was to match the existing as much as possible.
The beam further down holds significantly less weight so the end plate bolting is fine and was designed for the loads.
This one was always intended to have positive seating so the bolt at the end isn't designed for the full gravity load, it's roll protection as much as anything.

The pilaster has not failed, I did the pre pour and there is steel tying the pilaster to the wall
However something has gone wrong during the pour so the arch/contractor are working through it

The steel column is part of a two-storey moment frame hence its existence
The site has large retaining walls with constrained footprint, insurance constraints, and seismic loads
Hence the methods of construction may be different than typical for your areas...