Modern Steel Construction February 2012 : Page 43Various possible ybS configurations. stiffening due to second-order geometric effects. This stiffening behavior allows for a better distribution of yielding in braces over a building’s height at large drift levels. In the event that deformations begin to collect in a single story, the system’s post-yield stiff-ening and strengthening will cause braces in adjacent stories to be activated, thereby reducing the likelihood of the formation of a “soft-story”. Neither of these advantages is available in systems that exhibit little or no post-yield stiffness. Further, after a sig-nifi cant seismic event, the yielding fi ngers of the connectors are fully accessible and can be easily inspected for signs of severe inelas-tic deformations or damage. Scorpion connectors are produced through a highly controlled steel casting process that ensures excellent quality con-trol and a high repeatability of geometry and mechanical properties. It is envisioned that each unique connector from the series will be subjected to full-scale structural testing to confi rm the mechanical response of the standardized component. Then, the performance of subsequent production components can be assured through non-destructive examination of each part and the physical and chemical testing of steel produced from every heat. also For Retrofi t The combination of high stiffness and low activation force also makes the YBS ideal for retrofi tting seismically defi cient structures. The high elastic stiffness of the system can reduce the drift levels of older building frames while lower activation forces reduce costly remediation of mem-bers, connections and foundations. In fact, the YBS is currently being considered for use in the seismic retrofi t of a school in the ➤ Charlevoix region of Quebec, Canada’s most severe seismic region. Furthermore, because all of the inelas-ticity in the brace is confi ned to the Scor-pion connectors, engineers using the sys-tem have the fl exibly to employ a wider range of brace confi gurations than can be accommodated with other yielding brace systems. For example, a single-bay, single-story X confi guration can be employed to reduce the number of frames which are lost or obstructed. In the case of retrofi t, this confi guration can reduce the cost of the removal and replacement of building envelope and fi nishes. For more information regarding the Scorpion YBS including typical details, recommended design level deforma-tions for each connector, or for design assistance, contact AISC member Cast ConneX ( www.castconnex.com ). fabric structures FLEXIBLE FINANCE SOLUTIONS ON FABRIC STRUCTURES * TERMS UP TO 7 YEARS RATES AS LOW AS 4.99% AS LITTLE AS 10% DOWN *Subject to credit approval. solutions Sustainable design-build & more! for manufacturing, storage Call one of our ClearSpan specialists today at 1.866.643.1010 or visit www.ClearSpan.com/ADMSC. Low in cost per square foot. Natural daytime lighting. Easy to relocate. Expandable. february 2012 MODERN STEEL CONSTRUCTION 43 ClearSpan Fabric Structures |
