Reinforcing Steel - Concrete Cover

[hondashadow1100vt]

I am a PE (mechanical) working on a construction project. Our contractor is in the process of building reinforced concrete equipment bases for tanks, pumps, etc. The reinforcing steel and form work have been completed but concrete has not been placed. The design calls for the top mat of steel in the equipment bases to have 1-1/2" of concrete cover however, as constructed, the contractor has installed the steel to have 3" of concrete cover. I am not a structural engineer but I would like to be armed with a technical understanding of what could happen if the amount of concrete cover over the top mat of steel is not corrected. What are the technical problems that could result from leaving this matter uncorrected?

 

[hydrae]

This question should be posed in a concrete forum

but to respond as I remember
The distance between the re-bar and the center of the compression half of the section raised to the 2nd power is directly related to the bending strength
therefore decreasing this distance reduces the strength by a large amount quickly

Hydrae

 

[cvg]

except that top steel in equipment foundations is usually not in tension. better to have it installed correctly though if you are not the designer.