How do you determine the appropriate amount of concrete core samples?
How do you determine the appropriate amount of concrete core samples?
(OP)
All,
I am working for a concractor on a restoration of an existing 2 story building. The building has a foot print of 50ft x 300ft. The building has a concrete floor system for the 2nd floor. The restoration project requires some extensive modifications to the existing truss system that supports the roof. The building has high ceilings, and due to the loads of the steel components being used in the renovation, power equipment will be needed to hoist and hold the material into place. Using some simple beam analysis, using the EOR's Live design loads, I beleive that the girders and beams will support a piece of equipment.
One area of concern that I do have is in regards to the strength of the concrete floor itself. During my initial analysis I assumed a compression strength of 3000 psi. I then used the steps in ACI-318 (Chp. 22) to determine a unreinforced nomial shear and moment strength. These nomial values are setting the limits on the piece of equipment that can be used. To confirm my assumption, I have elected to hire a testing company to come out and take some cores of the 2nd floor. Hopefully this will atleast confirm my assumption, or better yet, allow my equipment load limits to increase. Which leads me to my question. How many core samples should I have the testing company take? Is there also a random sampling procedure that I should follow. I know the more samples the better the analysis, but wanted to know if there was either a certain ACI/ASTM procedure that I should follow, or a good rule of thumb, (ie, one core for every 1000 sqft or something like that).
Thank you for any advice or information that you can give.
LNT
I am working for a concractor on a restoration of an existing 2 story building. The building has a foot print of 50ft x 300ft. The building has a concrete floor system for the 2nd floor. The restoration project requires some extensive modifications to the existing truss system that supports the roof. The building has high ceilings, and due to the loads of the steel components being used in the renovation, power equipment will be needed to hoist and hold the material into place. Using some simple beam analysis, using the EOR's Live design loads, I beleive that the girders and beams will support a piece of equipment.
One area of concern that I do have is in regards to the strength of the concrete floor itself. During my initial analysis I assumed a compression strength of 3000 psi. I then used the steps in ACI-318 (Chp. 22) to determine a unreinforced nomial shear and moment strength. These nomial values are setting the limits on the piece of equipment that can be used. To confirm my assumption, I have elected to hire a testing company to come out and take some cores of the 2nd floor. Hopefully this will atleast confirm my assumption, or better yet, allow my equipment load limits to increase. Which leads me to my question. How many core samples should I have the testing company take? Is there also a random sampling procedure that I should follow. I know the more samples the better the analysis, but wanted to know if there was either a certain ACI/ASTM procedure that I should follow, or a good rule of thumb, (ie, one core for every 1000 sqft or something like that).
Thank you for any advice or information that you can give.
LNT
RE: How do you determine the appropriate amount of concrete core samples?
Given that, I would consider 6 to 9 cores, and possibly some consistency verification using either a swiss hammer or Windsor probe. This way you minimize the holes and maximize the relevant data.
ASTM C42 is the procedure for coring. Evaluation can be done under ACI guidelines.
RE: How do you determine the appropriate amount of concrete core samples?