Stirrup Repair in Spandrel Beam

[rsbmusicguy]

Hi All,

Am dealing with a heavily deteriorated spandrel beam on the perimeter of a building that has seen extensive water infiltration. The water infiltration has exposed the stirrups and longitudinal reinforcement at the underside of the spandrel beam. Additionally, the outermost longitudinal rebar has deflected up to 1.5" with some stirrups experiencing up to 100% section loss at these locations.

Surprisingly the deflected longitudinal rebar section is minimal and I am looking into an alternative to position the rebar back into place and repair the deteriorated stirrups but am having trouble trying to figure out a way to repair the stirrups. My only consideration is to possibly weld a piece of steel to maintain continuity of the stirrup? The spandrel beam is pretty big and by inspection, I am not concerned about shear (I will confirm this with analysis) but am worried about the role of the stirrups when torsion is applied to the beam. I am having a tough time to try and make these severed stirrups continuous once again...

Any help would be appreciated, thanks!

RSB

 

[JoelTXCive]

I don't know what the budget is, but that might be a scenario for a specialist engineer and some FRP Wrap.

I don't think it is cheap, but they can do some really cool stuff.

 

[hokie66]

Joel,
That concrete structure doesn't look like it has suffered from deterioration. Do you know why the FRP wrap was added? Inadequate design or unanticipated increase in loading?

 

[JoelTXCive]

That's just a repair photo I found on the internet. I was trying to find a photo where they did both flexural and shear reinforcement.

Here's a company with several photos on their website:

https://ctech-llc.com/en/wikitech/beam-strengthening-and-repair-with-frp-composite-system

(I know nothing of the company, I was just looking for photos)

If you google 'concrete beam frp shear repair' there are more photos and articles.

For a deteriorated beam, I would think that you would need to shore it somehow; then build back up the deteriorated concrete with a repair mortar.

Then, an FRP wrap could be installed and the shoring removed.

It's complicated stuff though. Aside from the FRP itself, you would get two interfaces that would require calculations. The interface between the repair mortar and the beam; and then the interface between the repair mortar and the FRP sheets.

I took a class in the stuff. It's awesome, but definitely a niche market requiring expertise.

 

[Tomfh]

Hokie66, that image is photoshopped.

 

[JoelTXCive]

Tom - I think you might be correct. Now that I look at the bridge photo; it does look a little strange or manipulated.

I apologize, I did not notice that last night. (I had my 2nd Covid shot yesterday and was out of it all afternoon/evening)