Forell Elsesser provided structural engineering services for the supporting frame of a distinctive 60’x30’x40’ stainless steel sculpture, famously known as “the Bean,” commissioned as the centerpiece of Millennium Park in Chicago.

The sculpture consists of meticulously welded stainless steel panels, meticulously ground to achieve a seamless, reflective surface. Design challenges included developing flexible connections between the stainless steel shell and internal steel frame to accommodate thermal expansion and contraction, as well as to withstand transportation stresses without compromising the sculpture’s smooth appearance.

Forell Elsesser’s role involved structural analysis to support Performance Structures, Inc. in designing the internal frame for staged construction and final installation. The primary system features two large internal rings with plate springs mounted to the frame, supplemented by triangular trusses for stability during construction.

• Fabricator: Performance Structures, Ethan Silva
• Sculptor/Artist: Anish Kapoor
• Owner: City of Chicago