Concrete Column Capacity, Reduced Cover
Concrete Column Capacity, Reduced Cover
(OP)
Investigating the moment capacity of some 1200 reinforced concrete Piles.
Due to a bad pour the cover has been compromised and has reduced strength, say 40Mpa in for 50Mpa design strength.
There are inclusions and voids in the cover region of the piles due to issues with bentonite. Some reo was exposed when investigated. The internal diameter within the bars appears sound after investigation.
The problem: There will be a reduced section capacity, I am going to do an analysis with Moment interaction diagram neglecting any cover, (ag cover = 0) for the structural analysis.
However with the cover compromised, can you still develop stress in the steel without the full bond of the bars within the concrete matrix?
Any ideas?
Due to a bad pour the cover has been compromised and has reduced strength, say 40Mpa in for 50Mpa design strength.
There are inclusions and voids in the cover region of the piles due to issues with bentonite. Some reo was exposed when investigated. The internal diameter within the bars appears sound after investigation.
The problem: There will be a reduced section capacity, I am going to do an analysis with Moment interaction diagram neglecting any cover, (ag cover = 0) for the structural analysis.
However with the cover compromised, can you still develop stress in the steel without the full bond of the bars within the concrete matrix?
Any ideas?






RE: Concrete Column Capacity, Reduced Cover
However since quite likely a proper model of the lack of bond (geometrical 3D shape of the situation will be lacking) you may add a factor to reduce capacity on such intent. If after rational estimate you still have reasonable doubt of the piles having the necessary strength, adding more or microplile may be the solution.
RE: Concrete Column Capacity, Reduced Cover
Is it just one pile affected or many? If just one has a check been made to see if the problem continues at a depth exceeding say -5m?
RE: Concrete Column Capacity, Reduced Cover
RE: Concrete Column Capacity, Reduced Cover
RE: Concrete Column Capacity, Reduced Cover
You can also solve the problem by adding sacrificial anodes "pukes", I believe Sika makes some, and i've specified them for concrete repairs. But...they have an effective distance. The other more complicated solution is to add active corrosion protection through an electric circuit.
RE: Concrete Column Capacity, Reduced Cover
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...or if all else fails...core a micropile(s) through the center.