ATLSS Report No. 10-06:
Self-centering steel concentrically braced frames (SC-CBFs) are being studied as part of an ongoing research program on self-centering seismic-resistant structural systems. This research was conducted at Lehigh University in collaboration with Princeton University and Purdue University under the NSF-funded NEESR program. Self-centering systems make strategic use of post-tensioned interfaces between main structural elements to create joints which open under seismic loading. The opening of gaps at these critical joints significantly increases the lateral drift capacity of the structure without causing serious damage to the main structural members.
Previous self-centering systems studied include unbonded post-tensioned precast concrete walls, unbonded post-tensioned precast concrete frames, and self-centering moment resisting frames with post-tensioned connections. The research showed that these systems could withstand the design basis earthquake loading without significant damage to the main structural members and with minimal residual drift.
The current research on SC-CBFs includes analytical parametric studies of a prototype structure designed for a site in Los Angeles, and the development of a reliability-based, performance- based design procedure for SC-CBFs. The research also features experimental testing of a 0.6- scale, four story SC-CBF at the NSF NEES RTMD Earthquake Simulation Facility at the ATLSS Engineering Research Center at Lehigh University in Bethlehem, PA. This report focuses on the performance-based design, experimental setup, material testing and stiffness testing of the 0.6-scale SC-CBF test structure.