During the initial structural condition analysis, it was noted that existing concrete walls were carbonated to a depth of 3 to 4 inches and destructive testing pointed out that the outer layer of reinforcing walls was placed approximately 1/2” from the finished exterior surface mainly due to the fast-paced construction of the Pentagon. This improper placement of the reinforcing steel, coupled with years of carbonation, had created an environment ideal for corrosion. Also, the last minute addition of a fifth floor after construction was well underway led to inadequate reinforcing bar splices between the fourth and fifth floors. All of these factors contributed to the fact that the lightwell walls indicated telltale signs of concrete spalling and exposed reinforcing steel corrosion. Approximately 20-30% of the exterior wall was in need of repair.
Delaminated, spalled, and cracked concrete related to steel corrosion was removed
down to sound concrete
Reinforcing steel was cleaned, treated with corrosion-inhibiting coating, and relocated
to provided adequate concrete coverage
Concrete repair material were installed mainly by form and pump methods. Intricate
formwork was installed to match the existing rough cut board finish. Result was that
the final product matched in color and texture.
Exposed concrete surfaces of the building were treated with an amino-based
penetrating corrosion inhibitor, silane sealer, and mineral based anti-carbonation
Full and partial depth column and beam repair requiring extensive use of shoring
Removal and replacement of miscellaneous floor coatings, expansion joints, and