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Tuesday, May 18, 2010 - 11:05 AM

Cyclic Testing of An SMA-Based Articulated Quadrilateral Bracing System

M. Speicher, R. DesRoches, R. T. Leon, Georgia Institute of Technology, Atlanta, GA

An articulated quadrilateral (AQ) bracing system is developed and tested for seismic resisting applications. The AQ setup provides a convenient means of combining in parallel NiTi wires with energy dissipating elements.  For these prototype tests, NiTi SMA wire bundles were combined with long C-shape energy dissipators in an attempt to create a system with a good balance of recentering and energy dissipation.  The bracing system maintained good strength, ductility, and recentering after being cycled up to 2% drift.  At 3% drift, the system began to lose recentering due to the SMA wires being strained beyond their superelastic range of approximately 8%.  By using the same basic bracing setup, a wide range of force-deformation responses are at an engineer’s disposal by simply varying the geometry of the AQ, cross-sectional area of the NiTi wire bundles, and the dimensions of the C-shape dissipators.    

Summary: Cyclic tests are carried out on an articulated quadrilateral bracing system incorporating SMA wire bundles and C-shape energy dissipators. This system was devised in order to create a lateral bracing system that would have a predetermined balance of recentering and energy dissipation for optimal performance under earthquake loading.