Jay Pritzker Pavilion Bandshell
Designed by the world-renowned architect, Frank Gehry, the Jay Pritzker Pavilion Bandshell is a highly sculptured design element that serves as a focal point for Chicago’s Millennium Park. Wallace Engineering worked with the architects and the skin fabricator to design the bandshell’s skin system and its attachment to the structure. The sculptured exterior reflects Gehry’s distinct style, wrapping the stage in a series of panels that erupt like petals of a flower across the expanse.
While the bandshell itself is approximately 60-feet high, it is decorated with unique steel ribbons that burst outward another 35- to 40-feet high. The twisting and hairpin turns of the “petals” consist of over 700 panels – no two alike. The panels, ranging from four to eight feet in width and six to 24 feet in length, are made from aluminum plates or fins, and are cut to the profile defined by Gehry’s computer model. The panels are held in place by 2,064 arms, and 5,200 interlocking stainless steel sheets cover the ribbons. The result is a series of shapes determined by the computer that are cut and assembled into frames on the shop floor, using computer numerically controlled equipment.
The challenge on these panels is that they are exposed to the elements on both surfaces. This requires wind forces to be applied to both sides of the panels and requires them to allow for expansion/contraction over a large temperature range. The panels are attached to the frame in two locations at the top, and hung from the steel frame. Each panel indexes into the panels below with large steel “fork plates” which transfer the wind force, but allow the panel to expand and contract individually to relieve thermal induced stress.