HARTFORD HEALTHCARE AMPHITHEATER, Bridgeport, Conn.
TENSILE ENCLOSURE ARCHITECT/ENGINEER: FTL Design Engineering Studio
BASE BUILDING ARCHITECT: Mingolello & Hayes Architects
BASE BUILDING STRUCTURAL ENGINEER: Szeker Engineering Inc.
MECHANICAL & ELECTRICAL ENGINEER: General Drafting & Design, (203) 239-6818
GENERAL CONTRACTOR: Joseph A Grosso & Sons LLC, (203) 336-9717
SPECIALTY STRUCTURE CONTRACTOR: Dunn
DEVELOPER: Howard Saffan, Bishop Development, (203) 277-4598
In 2017, the local minor league baseball team moved away, leaving the city with an empty facility. Local developer Howard Saffan, in association with Live Nation and the city, developed the empty ballfield into a covered outdoor music facility for an underserved performance market.
The existing stadium was in good shape, having been built in the 1990s. The design and construction team’s goal was to preserve as much of the existing facility as possible while augmenting it with a new enclosure. This required the design team to become forensic designers and engineers, examining the structure and foundations to determine where the strong points were located and where additional loads could be added; in addition, the existing tall bleachers required for sport sightlines would have to be covered.
Spanning an old ballfield with most materials—concrete, steel or glass—is difficult. Tensile approaches are desirable with their minimal weight on the existing structures. FTL Design Engineering Studio developed different design approaches and, with the owner, decided on a hybrid structure. Inserting a frame at the perimeter of the old ballfield and locating the stage at second base gave the orchestra and bleacher seating the ability to accommodate the required 5,700 seats.
The frame structure was in effect two different structures conjoined along a trussed gantry walkway, circling 80-feet above grade. The first structure covering the ballfield became a tensegrity roof with spans of 150 feet, using seven “flying masts” for a membrane roof. The second structure integrated this central tensile structure with the existing stadium, using framed steel trusses with a tensioned membrane. This skirt was supported in the open areas with piers to keep the perimeter open for exiting. In addition, an iconic entry wayfinding element was developed to draw spectators through ticketing and screening into the performance facility.
Using a structural membrane presents advantages and challenges. The fabric had to be structurally framed for curvature to resist wind pressures, luminous to allow for volumetric lighting and acoustically shaped to avoid trapped sound pockets. A luminous PTFE-coated glass fabric was used, which is non-combustible and boasts a lifespan in excess of 30 years. The areas where the flying masts join the fabric, ETFE foil skins bring in more light. Between the two structures was a black mesh fabric for passive cooling. In addition, large fans were located in the central space to circulate air in the summer months. New seating and a stage house were developed as a simple truss frame with metal cladding to mimic the curve of the fabric roof.
PTFE-COATED GLASS FABRIC: Saint Gobain