October 23, 2010 – A year and $1 million later, workers are finishing a massive project to repair concrete on Marina City’s residential towers, at one time the tallest structures made of reinforced concrete.

The exterior, high-rise work had to be done by the start of winter, but the workers themselves estimate they will be done during the first week of November.

With work on the west tower completed, a memo from the residential property management office at Marina City said workers were on the “last drop” of the east tower as of October 8. According to the memo to residents, “there have been no unexpected cost overruns.”

The work began in September 2009 to comply with a request by the city to repair problem areas identified by engineers inspecting the concrete in 2006 and 2007.

As seen in the sequence of photos below, each area of weakened concrete is cut into, exposing the steel reinforcing bars. The rebar is then sandblasted, sealed with epoxy, and covered with a special adhesive-added concrete. (Click on images to view larger versions.)

Workers visited 16 balconies on each of 44 residential floors in two towers. The project will cost condo owners at Marina City $1,023,500.

 Related story: Concrete repair scheduled for residential towers (September 20, 2009)

	High-rise repair act (Left) Kneeling on a small platform suspended between two balconies 37 floors above ground, Juan secures a wooden form that will hold new concrete as it dries.
	As Jorge retrieves the platform, Juan steps back into the scaffold.
	(Click on images to view larger versions.)