steel rebar installation depth in concrete wall

[jikewang]

Hi, everyone! I'm a novice in the field of structural engineering.

Recently, I found a rebar corrosion detection system called iCAMM (Inspecterra), which detects rebar using magnetic fields. However, I noticed that the detection range is limited to 3–10 cm.

I wonder that: is this sensing range sufficient for detecting rebar embedded in walls of typical buildings (e.g., houses)? I found that wall thickness varies with different wall types. For example, load-bearing walls can be as thick as 300 mm.
What happens if the rebar is installed at a depth exceeding 10 cm within the wall surface? does this situation happen in daily scenario?

I have learned from the ACI standards that rebar installation typically only needs to meet minimum concrete cover requirements (usually just a few centimeters), and single or double rebar layers are sufficient for most buildings due to cost-effectiveness.
Additionally, rebar is usually installed closer to the load-bearing surface, rather than the middle of the wall, even for thicker walls.
Based on these, I guess 3~10 cm can be adequate for the majority of wall types? Is my assumption correct?

Lastly, are there official guidelines that define the clear depth of rebar installation and wall thickness for different wall types?

Looking forward to insights and advice from the experts here!

 

[EngDM]

Rebar is typically installed close to the faces of concrete (with varying cover depending on application but nothing as high as 10cm AFAIK) so you can benefit not only from strength but also stop the concrete from spalling and offer some crack control. In cases where a single layer of central reinforcing is allowed, there are maximum wall thicknesses and restricted use cases.

 

[Lomarandil]

Agreed, 3-10cm is suitable for detecting bars in all but the largest structures, assuming you have access to both sides of the wall (or all sides of the column, etc).

There are official guidelines defining minimum clear depth (cover) of rebar in your relevant concrete building code document. Many scenarios do not have a maximum limit for clear depth, but other factors make it unusual to significantly exceed that minimum depth.