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.