The developer of Symphony House, a 32-story, $125 million condominium, promised “a provocative design that takes from the grandeur and romance of the 1920s and gives it 21st century transformation.” The same can be said about the building's exterior, featuring almost 900 CarbonCast carbon fiber, reinforced, architectural wall panels.
CarbonCast panels use non-corrosive, high-strength, resin-bonded, C-GRID carbon fiber reinforcement in the panel face, replacing conventional steel mesh. Ultra-strong, 1-mm-thick, C-GRID requires less concrete cover than welded wire, enabling lighter pre-cast sections and longer life.
This technology permits panel thicknesses of 1 ¾ to 10 inches or more, allowing design freedom with no weight penalty, less overall mass, less energy to install, and lower shipping and erection costs. All of this translates to a smaller CO2 footprint.
The high-performance 5000 psi panels for Symphony House consist of recycled and local materials. The panels were 7 inches thick and deeply articulated, but weighed 66% less than conventional precast, so they could be slab-attached. This resulted in fewer interior columns and more open spaces. Although the 507,000-square-foot building sits on poor soil, the carbon fiber panels allowed better seismic performance, but with fewer columns and less structural mass than conventional precast.
Carbon fiber panels are energy-efficient, as the carbon fiber shear truss provides low thermal transfer between a steel-reinforced v-rib and the panel face. Crews embedded expanded polystyrene (EPS) foam in the panels for insulation, improving energy efficiency and reducing weight.
Symphony House's insulation has a composite value of R-9, a value not possible to achieve with conventional pre-cast panels. Each inch of insulation on this project also cost about half as much as it would for solid concrete paneling.