NCHRP-IDEA 172: Bidirectional-Ductile End Diaphragms for Seismic Performance and Substructure Protection

Principal Investigator: Michel Bruneau

PhD Student: Xiaone Wei

Start Date: 6/1/2013

End Date: 12/31/2015

Abstract: This project will develop bi-directional ductile diaphragms for implementation in straight and skewed bridge superstructures to provide resistance to bidirectional earthquake excitations. Work involves non-linear time-history dynamic analyses to investigate the seismic performance of bridges with the proposed bi-directional ductile diaphragm concept, considering variations in skew, span length, reactive mass, fundamental period of vibration, and earthquake excitation characteristics. The dynamic analyses will allow investigating the impact of these parameters on global behavior as well as an understanding of the magnitude of local demands and the extent of bi-directional displacements that the hysteretic devices must be able to accommodate while delivering their ductile response. Work is also conducted to identify effective and practical details for hysteretic energy dissipating devices. Research also involves scaled experiments to subject selected device and connection details to a regime of relative end-displacements representative of the results predicted from parametric analytical studies. The outcome of this part of the project will be an understanding of expected dynamic seismic performance as a function of key design parameters, and viable hysteretic devices and connections schemes.