CompositesWorld
Issue link: https://cw.epubxp.com/i/620463
JANUARY 2016 24 CompositesWorld INSIDE MANUFACTURING ยป Te use of fber-reinforced composites in architectural appli- cations is on the rise, often adopted for the design fexibility they ofer. Tis was indeed the case for a self-supporting spiral stairway for a residential project designed in 2015 by William McDonough + Partners (Charlottesville, VA, US) in partnership with stairway consultant Charlie Lovely. Instead of a traditional spiral staircase, where the stairs are supported from a central pole, the team conceived a stairway that would feature an outer curved spar structure from which the stairs are cantilevered with a central core that is open, termed a cascading stair. Although carbon fber-reinforced plastic (CFRP) was a new material for the architects, it was chosen for the stair- case build because the cutting, bending and fnal surface fnishing of steel to achieve the complex design would have been prohibi- tively expensive. While the stairway's outer curved spar would faunt its carbon fber structure visually, the CFRP stairs would be clad in white oak veneer. Glass balustrades would spiral up both sides of the stairway, supported within a groove in the CFRP struc- ture and capped by a white oak rail. Naval architect Eric Sponberg (Sponberg Yacht Design, St. Augustine, FL, US) was contracted as the liaison for composites structural engineering. Of the seven companies that responded to his request for proposals, and of the three short-listed for the job, selectee Clear Carbon and Compo- nents (Bristol, RI, US) was the only one with in-house 3D modeling, CNC-machining and a storyboard explaining how it would build the staircase. "Te design presented a signifcant challenge for fabrication," explains Clear Carbon president Matt Dunham. "No one could fgure out how to make it in one piece." Clear Carbon and Components produces high-performance, high- quality aesthetic parts made from a wide range of composites, with special expertise in CFRP. Although a signifcant part of its business is high-end production parts for other companies, including musical instruments, yacht ladders and components for aerospace and naval applications, By Ginger Gardiner / Senior Editor Composites fabricator uses digital techniques and an innovative molding approach to actualize architect's customized residential stairway. Structural work of art Freestanding, one- piece spiral staircase A rendering of the fnished cascading stair (fnal installation was pending as this story was prepared). The staircase features a one-piece spiral spar that supports cantilevered stairs, all made from carbon fber-reinforced polymer (CFRP) because it ofered design and production fexibility unavail- able with steel at a competitive price point. Source | Charlie Lovely