Repairing damaged stirrups

[JoeBaseplate]

So I have a condition where one side of the beam stirrup has had significant rust. See attached for a schematic layout. How do I go about replacing the damaged leg of the stirrup? I understand that there are hook requirements for stirrups per section 7.1 ACI but I don’t see a practical way to achieve the hooks. Can I drill and epoxy in a half tie as shown on the sketch replacing one vertical leg of the existing stirrup?

 

[hokie66]

I wouldn't consider doing as per your sketch...too much drilling, depending on adhesive, development in the cover concrete, etc. Welded splices to the existing may be an option.

 

[msquared48]

That's what I was thinking too.

Just install a new leg with a hook at the top and weld the bottom to what's remaining. Simple.

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

 

[kieran1]

If there is significant rust on one side as your sketch suggests, I would also be worried about the main steel. If you need to replace shear reinforcement, in this instance I would be quite worried

Kieran

 

[JoeBaseplate]

Hokie, Mike, you mean weld the new piece directly to the existing piece or would you rather use a coupler? The problem with coupler is that there won't be enough concrete cover. It would be great if the two pieces can be simply welded together. Are there any guidelines on ACI for welds?

 

[hokie66]

Look at ACI 12.14.3.3 and the Commentary to 3.5.2. Basically, welded splices are allowed, provided they are done in accordance with the welding code, which in your case I believe is AWS D1.4. Other than replacing the damaged reinforcement, make sure you determine why the corrosion occurred and do the repair in a manner which will ensure future durability.

kieran1, in many cases the ligatures corrode substantially, enough to cause spalling, without damage to the main bars.