By Frank Rausa
Lorado Taft’s 50-foot-tall Eternal Indian statue (“Black Hawk”) at Lowden State Park, Oregon, Ill., was constructed out of concrete in December 1910, then later unveiled and dedicated in July 1911. During construction, the concrete was monolithically placed in lifts with a thick interior structural concrete with a hollow void in the center, and an approximately 2-inch-thick exterior finish concrete. The 103-year-old statue has lived through several previous repair projects, most recently in circa 1990.
Current damage to the statue prompted the recent Phase 2 Investigation and Documentation project. Thornton Tomasetti, Chicago, was contracted in October 2013 to undertake this recent investigation, which is a follow-up and more detailed investigation than the previous limited study conducted by Thornton Tomasetti in the latter part of 2008.
The four purposes of the Phase 2 study are to:
1) Assess the current condition of the statue
2) Determine the composition and chemistry of the original concrete materials used during construction
3) Evaluate previously implemented repairs and treatments and how they affected the statue
4) Develop a restoration plan, which is slated to begin in the summer of 2014
In October 2013, a team from Dynasty Group, Chicago, used digital laser scanners to document the existing shape of the Black Hawk Statue. Thornton Tomasetti’s Research and Development Group, New York, N.Y., used this data to create a 3D model of the statue. Dynasty Group also used non-destructive testing (e.g., ground-penetrating radar) to determine the location of some of the reinforcing steel bars within the statue.
In April 2014, an up-close investigation was performed by Thornton Tomasetti using an articulating boom lift to be able to access most of the statue. During the investigation, much of the statue’s surface was sounded using a metal probe to determine areas that are unsound or delaminated. Up-close observations were made, and significantly damaged areas were documented. The arms, the areas under the arms, the vertical fold in the robe, and a large section in the middle of the robe were found to have the most damage.
Samples were removed from the statue and sent to Schmitt Technical Services, Inc., Cross Plains, Wis., for laboratory petrographic analysis to determine the composition and condition of the outer finish concrete and the condition of the structural concrete. Some of the samples were miscellaneous pieces that fell from the statue and were collected at the base by Lowden State Park staff. Samples were extracted from selected locations on the statue. The laboratory results helped to understand the current condition of the concrete and will be used to replicate the original concrete mix used in the outer finish concrete.
Results from the current investigation of the Black Hawk Statue are much more significant than was anticipated and greater than what was documented in Thornton Tomasetti’s 2008 report. This past winter also played a role in the statue’s deterioration as the damage is even more severe than the laser scanning documented in October 2013. Some areas are so badly deteriorated that engineers were unable to sound the concrete for fear of dislodging the delaminated concrete.
Water infiltration continues to cause damage to the statue. Efflorescence and calcium carbonate deposits are signs of water infiltration and are visible at many of the cracks on the statue. Most significant locations where efflorescence is leaching can be found on much of the front of the statue near spall and delaminated areas as well as on the sides below the statue’s arms. Full restoration of the statue is now at a critical state in the statue’s life.
About the Project Team:
Ms. Amy Lamb Woods, P.E., Thornton Tomasetti, serves as the project manager and preservation materials engineer. Woods has 15 years of experience in the field of historic preservation and forensic engineering of materials and construction systems. She has a B.S. and M.S. in architectural studies from the University of Illinois with a focus on historic preservation; and a M.S. in civil engineering building materials with a focus on concrete and cement chemistry. This restoration project utilizes findings from her research to help match historic concrete in order to preserve the Black Hawk Statue.
Dr. Andrzej Dajnowski, Ph.D., serves as the team’s conservator. Dr. Dajnowski received his doctorate from the University of Nicolaus Copernicus, Torun, Poland. He worked for nine years as a sculpture conservator for the Chicago Park District and the Art Institute of Chicago. He was responsible for the restoration of Lorado Taft’s Fountain of Time in Chicago.
Ms. Anne T. Sullivan, FAIA, serves as the historic preservation consultant. With more than 20 years of experience in the field of historic preservation architecture, she has a B.A. in art history and a B.S. in architecture from the University of Illinois at Urbana-Champaign and a M.S. in historic preservation from Columbia University. Currently, she is the director of the graduate Historic Preservation program at the School of the Art Institute of Chicago and maintains a private consulting business.
Ms. Charron Rausa, Sterling, Ill., a member of the Friends of the Black Hawk Statue, said, “Through grants received from the Illinois Department of Commerce and Economic Opportunity, the Jeffris Family Foundation, the Chicago Blackhawks hockey team and donations from foundations, individuals, the Oregon Trail Days Festival and “Pennies for Black Hawk” from schools in Sterling and Oregon, Ill., over $700,000 has been raised.”
More funds needed
As a result of further damage to the statue, it is estimated that additional funding will likely be needed to complete the restoration of the Black Hawk Statue.
Tax-deductible donations can be made at www.ilcf.org or sent to: Illinois Conservation Foundation, One Natural Resources Way, Springfield, IL 62702. (Indicate the donation is for the Black Hawk Statue.)
For more information, contact Frank Rausa at (815) 370-8757 (cell), (815) 626-8757 (home) or firstname.lastname@example.org.
From the July 2-8, 2014, issue