ClientMB Real Estate Services, LLC
BackgroundAt 50 feet tall, Pablo Picasso's untitled, enigmatic sculpture strikes an imposing figure as the centerpiece of Chicago's Richard J. Daley Plaza. Constructed from 162 tons of weathering steel, the Cubist monument was manufactured at U.S. Steel in Gary, Indiana, and shipped by barge to Chicago for assembly and installation. Although financed by three private donors, the sculpture was dedicated in 1967 to the citizens of Chicago and remains a city landmark today.
SolutionAs a part of the condition survey and document review, WJE specialists conducted a variety of field tests to identify and assess the source of corrosion. The investigation determined that water collection in joints and crevices had eroded the rust-like protective layer distinctive to weathering steel, exposing it to the degenerative effects of moisture. Accordingly, WJE designed a tailored conservation approach to correct the corrosion damage and mitigate future deterioration.
To remove corrosion scales and debris in the base cavity, WJE preservationists combined light-impact hammering with moderate pressure hot water. The preservationists also installed silicone sealant "water sheds" to deter water accumulation in the facial features of the sculpture and resealed gaping joints to increase water resistance. Furthermore, magnetic particle testing revealed several weld cracks for which WJE prepared precise repair guidelines, specifying the weld type, size, and preheat temperature. Finally, WJE evaluated alternative, nonabrasive cleaning methods to reduce surface streaking and discoloration as part of a detailed strategy for future maintenance.