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Evaluation of the Concrete Columns
Office Building
 Difficulties
were experienced during concrete placement of some of the building
columns and exterior walls. Resulted surface imperfections were patched.
However, the City Inspector expressed concerns regarding the internal
quality of the concrete. Patched concrete on one of the columns was
chipped out and large areas of honeycombed concrete and voids were
discovered. As a result, the Architect as well as the Building Inspector
requested to test the suspect area of the columns and walls to determine
the internal condition of the concrete.
Concrete Science, Inc. used pulse velocity and impact-echo, both nondestructive
techniques, to evaluate the concrete of the columns and walls. Pulse
velocity readings were taken at every 1-ft. interval starting at 3-in.
from the bottom of each column. The measured transit times on the
columnswere mostly consistent except at the bottom of the columns.
The results were confirmedby chipping the concrete at these locations.
All suspect locations showed honeycombed concrete around the reinforcing
steel.
 Impact-echo
tests were conducted on the exterior walls. The test results showed
insignificant voids and honeycombed concrete. Again, the results were
verified by chipping out the concrete which revealed minor honeycombing,
very close to the surface.
Concrete Science, Inc. gave the Architect and the Engineer guidance
in choosing the repair materials and procedures. |
