Abstract
The ductile end diaphragm concept developed for regular (i.e., straight) slab-on-girder or deck-truss steel bridge superstructures is expanded to make it applicable to bidirectional earthquake excitation. Buckling restrained braces (BRBs) are used as the ductile fuses. Two retrofit schemes (Retrofit Scheme-1 and Retrofit Scheme-2) are investigated to seek the best geometrical layout to maximize the dissipated hysteretic energy of the ductile diaphragms with BRB end diaphragms. Closed form solutions are presented for practical design purposes. Behavioral characteristics (strength, stiffness, and drift) of the proposed retrofit schemes for end diaphragms are quantified with an emphasis on hysteretic energy dissipation. Results from selected numerical examples show that the generic bridge geometry, bidirectional loading, and the loading ratio (or the assumed combination rule), have a pronounced effect on the end diaphragm's inelastic behavior. Volumetric hysteretic energy dissipation is used to compare the effectiveness of the proposed retrofit schemes under several loading cases. These indicate that, in most cases, Retrofit Scheme-1 is superior to Retrofit Scheme-2 and may exhibit better seismic response.
Original language | English |
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Pages (from-to) | 380-393 |
Number of pages | 14 |
Journal | Engineering Structures |
Volume | 31 |
Issue number | 2 |
DOIs | |
Publication status | Published - Feb 2009 |
Funding
This research was conducted at the State University of New York (SUNY) at Buffalo and was supported by the Federal Highway Administration (FHWA) under contract number DTFH61-98-C-00094 to the Multidisciplinary Center for Earthquake Engineering Research (MCEER). However, any opinions, findings, conclusions, and recommendations presented in this paper are those of the authors and do not necessarily reflect the views of the sponsors.
Funders | Funder number |
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Federal Highway Administration | DTFH61-98-C-00094 |
State University of New York |
Keywords
- Bidirectional earthquake effects
- Ductile end diaphragm
- Hysteretic energy dissipation
- Seismic retrofit
- Straight steel bridges