Located at the Palo Alto Junior Museum & Zoo, this interactive art installation designed by artist Charles Sowers consists of four 40-foot-tall pivoting aluminum poles that penetrate through an opening in the main entry portico of the museum. The poles swing in a pendulum motion as visitors push and ride at the bottom. When not in use the pendulums also naturally swing back and forth due to wind.
Structural support is provided by a welded steel tube frame that is hung from the portico framing. The primary steel gussets, which connect the pendulum frame laterally to the support frame, are slotted vertically at the bolted connections to allow for precise leveling during installation. A detailed three-dimensional analysis of the frame was performed taking into consideration wind and seismic loads as well as impact loading from the poles onto the frame. A fatigue analysis of the poles was also performed due to the dynamic nature of the installation.