Aug 2012

NSF Project Funded to Study Self-Centering Moment Frames

A research project was funded by the National Science Foundation to develop new self-centering moment frames.  Stay tuned for more information as our research group makes progress on this exciting project!

http://www.nsf.gov/awardsearch/showAward.do?AwardNumber=1200237

Abstract:

An innovative new self-centering truss moment resisting frame (SC-TMRF) is devised to make building frames more resilient to earthquakes and reduce associated damage. The SC-TMRF consists of a truss with an assembly of concentric tubes at the bottom chord that creates restoring force in conjunction with post-tensioning strands. Conventional seismic force resisting systems use inelasticity in structural members and connections to dissipate seismic energy and protect buildings against collapse. However, the structural damage distributed throughout a building and related permanent residual drifts can make a conventional structure financially unreasonable to repair following a large earthquake. Recently developed seismic systems that mitigate residual drifts suffer from difficult or complex field construction, large cost premiums, and challenges associated with deformation compatibility. The unique configuration of the SC-TMRF solves many of these problems. Furthermore, steel plates with cut-outs leaving butterfly shaped links act as structural fuses, dissipate seismic energy, and can be readily replaced if necessary. The research project will develop the SC-TMRF concept through component testing, large-scale system experimentation, computational simulation, and the creation of proven set of design guidelines that will allow the application of the SC-TMRF concept in practice.

The SC-TMRF uses common materials in an innovative configuration. Preliminary design and analyses suggest that the SC-TMRF virtually eliminates permanent drifts, concentrates structural damage in structural fuses that can be easily replaced after severe earthquakes, can be shop fabricated allowing conventional field construction methods, and utilizes approximately the same amount of steel as conventional moment resisting frames. Because the SC-TMRF is a self-centering seismic force resisting system that is expected to be competitive with traditional systems, the SC-TMRF is a transformative new technology that has the potential to significantly reduce the economic losses due to earthquakes through a competitive building system that may not require structural repair after most earthquakes.