Further Development of Tubular Eccentrically Braced Frame Links for the Seismic Retrofit of Braced Steel Truss Bridge Piers

Keywords: Retrofitting.  Braced steel truss bridge piers.  Eccentrically braced frames.  Self-stabilizing tubular links.  Seismic load resisting systems.  Finite element (FE) analyses.  Parametric studies.  Design parameters.  Link rotation capacities.  Energy dissipation.  Overstrength.  Structural behaviors.  Rectangular link cross-sections.  Web compactness.  Flange compactness.  Local buckling.  Strength degradation.  Ductility.  Seismic performance.

Abstract: This report is a continuation of research on eccentrically braced frames with self-stabilizing tubular links for use as both a retrofit alternative and seismic load resisting system for new bridges (see Technical Report MCEER-05-0004).  A finite element parametric study was performed to investigate the effects of key design parameters for rectangular link cross-sections on link rotation capacity, energy dissipation, and overstrength.  Results from this parametric study were used to develop proposed design recommendations and provide insight into the behavior of tubular links.  An experimental program was developed to test fourteen links with cross-sections that were at the revised limits for web and flange compactness and four different link lengths.  The results provided in the report indicate that the design recommendations are successful in achieving links that can sustain their target rotation prior to strength degradation from local buckling.  An abstract, figures, and references are included.