Changing concrete corbel to straight wall?

[bigrod223399]

I have a concrete corbel that supports a slab. The contractor wants to simplify the formwork by just making it a straight wall down instead of forming the actual corbel shape (essentially providing a thicker wall). Do you think I'd need to change the reinforcement pattern, or will the added concrete section just act as more cover? Note: I am under the guidance of a senior engineer, just wanted to see what other people thought as well.

 

[jayrod12]

You would need to ensure the new wall dimensions and the reinforcing spec all worked out accordingly. I would not just be providing 4" of additional cover on the bars.

You may have to increase the reinforcement slightly to meet minimums, but otherwise I don't see why it's a bad idea. Depending on how tall the wall is, also could theoretically affect the foundation loads, but I'd expect that impact to be extremely minor except in rare cases.

 

[phamENG]

I agree with jayrod - you'll need to go back and check minimums based on the new section. That may involve new reinforcement sizing, new joint layouts, etc. Could be a fair amount of work for you to simplify the contractor's job.

There could also be architectural impacts. Those 4 to 6 inches may not seem like much, but they could directly impact things like ADA layouts in bathrooms. In a large enough building, it could have a significant impact on the area available to lease out to tenants, which could hurt the developer/owner's bottom line for decades to come.

 

[jayrod12]

Yeah, pham makes a ton of good points why it could be a bad idea, most of those architectural, which I would assume you would have them sign off on the lost floor space. But they are concerns nonetheless.

 

[bigrod223399]

Thanks all, I appreciate the good responses. Will definitely get the architect involved.

 

[chris3eb]

It looks like you're in New York, so it may not matter for you, but for seismic I sure wouldn't want to be adding an extra 50 psf of weight to my wall section.