The 22-foot-tall Alma sculpture is constructed of stainless-steel pipes and solid rods that evoke the undulating shape of a ship’s sails. It was installed outside the Office of the County Medical Examiner in San Francisco in November 2017. The sculpture is composed of two individually curved “sail” assemblies that meet at a single point at the center of the sculpture. One sail has two supports at the base and the other sail has one; when the two sails are connected to each other, they form a tripod.
The artist’s 3D model was imported into a structural analysis program to design for the sculpture’s self-weight and loading from wind, earthquake, and the possibility of people climbing on the structure. The main design challenge was ensuring stability of the sculpture given the aesthetic limitations. The two sails rely on each other for stability; it is only through their connection to each other that a tripod base is formed. The connection point of the two sails was one of the main challenges, and close coordination with the artist was required to find an appropriate solution.
The design solution involved adjusting the “seam” members—the larger steel pipe spines that run horizontally across each sail—to align between the two sails. These seam members, in addition to several surrounding smaller members, were designed to connect the two sails together at mid-height. The inherent flexibility of the structure and three-dimensional curved geometry of the sails made analyzing the structure a complex, iterative process to decide which members could be lightweight hollow pipe, which could be heavier hollow pipes, and which needed to be solid rods. Through extensive coordination and iteration with the artist and feedback from the steel fabricator, an elegant design was achieved that met the artist’s vision.
Photo Credit: Courtesy of Richard Deutsch Studio