Precast Wall Panel - Crack at Connection

[Structures33]

What is typically done to repair a cracked connection area (at the welded conn plate) on a precast wall panel? See attached photo please.

 

[dcarr82775]

This crack almost looks like the concrete overlapped the embed plate a little, and when the panels moved a little it spalled the corner off. Still nothing to worry about

 

[sonofamsquared48]

slickdeals - well, I know that the handle has some evil overtones although, being his progeny, I have recieved a heavy dose in the genes. I know that he will counter. All in good fun.

I believe as well that the connection is not really much of a structural concern. But still needs to be fixed. When I look at the root of the weld nearest the spaul, it looks rather healthy. I am siding with expansion of the plate due to the welder not allowing the weld to cool as well as maby the base plate not being thick enough to provide for a proper heat sink.

Cheers all

 

[hokie66]

The two photos are of two different connections. If you look closely at the first photo, there is a crack on the right side some distance from the joint. To me, that discounts the theory that this is only localized due to welding heat. The cracking is due to restraint of volume change due to shrinkage and/or ambient temperature variation.

I would cut loose all these connections before bothering to do any repairs, as otherwise the problem will just repeat. If this were my new building, I would not accept that it is "nothing to worry about".

 

[civeng80]

I agree with Hokie66. The right crack in the first photo would be due to movement and shrinkage and is more incidious and serious, this one will grow. If this was my building I would be concerned. The connection is not a good connection.

Just for the record, I would join the panels with a fish plate bolted to ferrule bolts with slotted holes (recessed if concealment is required).

As a matter of interest what would you guys do to join the panels?

 

[msquared48]

In the secondphoto, the gap appears excessive in width - I would guess 1.5 to 2". Must be a longer pair of panels.

The connection is rigid too - cannot expand or contract. No wonder the failure.

I have already described the connection I would have used.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[civeng80]

If this was my project, I wouldn't be welding the 2 panels together.

 

[msquared48]

Ron and Civeng80:

The movement need not be just due to temperature, it could also come from the normal shrinkage of the curing process. Can be quite a bit in panels of that size. I expect something on the order of 1/4" over the width of each panel.

OP:

How old were the panels when they were picked?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[msquared48]

OP:

Additionally, how old were the panels when the welds were made?

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[Structures33]

I would say the panels were between 3 and 4 weeks when they were placed. It was another week before they started the welding on the ones that were shown in the pictures.

 

[hokie66]

Doesn't matter. Drying shrinkage continues for a long time, and ambient temperature variation is always there.

 

[civeng80]

I think with concrete panels (and masonry also) its best to allow for as much flexibility in joints as possible. So its probably better not to tie the panels up at all. There will always be movements from temperature, shrinkage, foundation movements, creep and maybe more.

Without knowing the complete structural arrangement, however, I cannot comment this.

 

[civeng80]

mssquare48

Couldn't agree more with your comment on movements of large panels.