Precast Double Tee Bearing Displacement

[TRAK.Structural]

A contractor client sent me some photos of a precast parking deck that has some damage. At one location it looks like the bearing connection at the end of a double tee has failed and the tee has displaced. Can't tell from the picture if this double tee has a dapped end or not. Has anyone seen something like this before? Are there any resources out there from PCI that show common bearing end details and common repair schemes for these types of structures?

 

[BridgeSmith]

At this point, you probably need to retrofit a corbel anchored into the wall or a pilaster to the floor to support it.

To avoid future problems, you'll need to determine what moved, and mitigate it.

 

[TRAK.Structural]

At this point, you probably need to retrofit a corbel anchored into the wall or a pilaster to the floor to support it.

To avoid future problems, you'll need to determine what moved, and mitigate it.

A new corbel would put moment into the supporting wall that likely would not have been accounted for in the design of the wall. A new pier, anchored to the wall and extending down to the foundation would have to pass through the "floor" of lower levels which seems like would be a huge pain.

 

[phamENG]

Looks less like something moved and more like the bearing spalled off allowing it to fall straight down.

Water running down through from above (where it's obviously wet) and rusting those bars and blowing out the concrete seems likely. The fix will likely be a pain. But a lot less painful than that thing falling on your head.

 

[TRAK.Structural]

Looks less like something moved and more like the bearing spalled off allowing it to fall straight down.

Water running down through from above (where it's obviously wet) and rusting those bars and blowing out the concrete seems likely. The fix will likely be a pain. But a lot less painful than that thing falling on your head.

Yea that's my first impression too. Looks like there may be some cracking around where the flange/slab meets the web which would be my biggest concern for being able to re-form the bearing and set the tee back in place.

 

[ANE91]

You’d be surprised to know how often this happens to corbels, either because the design was bad or the rebar cage was misplaced in the form. Can’t say I’ve ever seen the flange delaminate like that (las photo). Scary. My vote is no dapped end. Jack it up and rebuild the wall/bearing, as a “bandaid.”

 

[BAretired]

Looks like the contractor should get a shore under the web in photo #2 and #3 (photo #1 is a smaller version of photo 2).
Not sure what the black stuff is...could be some kind of fill...could be just a void.
Needs inspection to determine how much bearing is available and whether or not the web is dapped (doesn't look like it).

The simplest repair for #2 is to fill the gap with grout, if that is possible, and provided there is sufficient bearing on the wall. It looks like the wall was saw-cut to create space for the web.

Hard to say about #3, but it looks like the double tee is just hanging from the flange in that location. Need to find out.

It is possible a permanent shore is required in both locations. Needs a proper study.

 

[BridgeSmith]

A new corbel would put moment into the supporting wall that likely would not have been accounted for in the design of the wall.

You may be correct. The wall would need to be analyzed for the loading.

A new pier, anchored to the wall and extending down to the foundation would have to pass through the "floor" of lower levels which seems like would be a huge pain.

Probably, but what other alternative is there? It's got to be supported somehow, or that section of the parking garage should be shut down permanently. Hopefully, it's shut down now until the beam support is restored.

 

[TRAK.Structural]

You’d be surprised to know how often this happens to corbels, either because the design was bad or the rebar cage was misplaced in the form. Can’t say I’ve ever seen the flange delaminate like that (las photo). Scary. My vote is no dapped end. Jack it up and rebuild the wall/bearing, as a “bandaid.”

That may be a solution if there is enough bearing length. The spalling doesn't look that deep but hard to tell from the pictures. The crack at the flange is problematic.....

 

[TRAK.Structural]

You may be correct. The wall would need to be analyzed for the loading.

Probably, but what other alternative is there? It's got to be supported somehow, or that section of the parking garage should be shut down permanently. Hopefully, it's shut down now until the beam support is restored.

Agreed that an easy fix here may not be possible. if the double tees below are all aligned than the pier probably cant go down because it would interrupt the webs/bearing of each tee it passes through. Maybe some FRP reinforcing on the outside face of the wall panel to resolve the tension side stresses from a new corbel would work.

 

[Tomfh]

Seems a very common problem. The bearing length is often way too short.

There’s one in Sydney (Goulburn St Carpark) where they retrofitted steel columns throughout.

 

[TRAK.Structural]

Seems a very common problem. The bearing length is often way too short.

There’s one in Sydney (Goulburn St Carpark) where they retrofitted steel columns throughout.

Ouch. Wouldn't want to be the one responsible for whatever mess up required that fix!