Marianne Russell-Marti and Robert F. Marti
This paper discusses the structural aspects of treatment of a large scale late 19th- early 20th century Japanese cast bronze eagle located outdoors on the Ward Parkway in Kansas City, Missouri. The eagle weighs approximately 800 pounds, with a wingspan of fourteen feet, and rests on a cast bronze, 5-foot tall hollow mountain/base. The alloy is a typical Japanese art bronze alloy, karakane, containing a 15% lead content. The sculpture was originally constructed in several discreet sections, including the eagle body, the wings, the head and neck, and the mountain/base. These sections were fitted together by means of mechanical attachments.
By 1935, the original wrought iron interior armature had deteriorated, and the sculpture was with filled with concrete and rebar in an effort to hold it together and to give the sculpture stability against tremendous wind uplift under the wings. The presence of the concrete eventually caused severe damage to the bronze, rupturing the sculpture through the action of freeze/thaw cycles.
The sculpture was treated by Russell-Marti Conservation Services, from the Spring of 1990 to November of 1991. The sculpture was disassembled, and the concrete interior was removed. An interior support system was designed and fabricated, using high-strength brass of a compatible alloy to the bronze. Where possible, the original concepts in supporting and joining the various parts of the sculpture were recreated. The Copper Development Agency (CDA) was consulted for advice on the alloy and the physical configuration of the various parts of the new armature. The design of the new armature is such that the weight of the entire sculpture is borne by the armature, with no localized stresses on the eagle or the base. The entire assembly can be easily dismantled in the future, should that be necessary.
Brief mention will be made of other phases of the treatment of the sculpture, including repair of ruptures and casting flaws (using patches and welding), removal of corrosion products, patination and construction of missing parts.