NEHRP Clearinghouse
- Title
- Seismic Behavior of Bidirectional-Resistant Ductile End Diaphragms with Unbonded Braces in Straight or Skewed Steel Bridges.
- File
- PB2008105141.pdf
- Author(s)
- Celik, O. C.; Bruneau, M.
- Source
- Federal Highway Administration, Washington, DC.; National Science Foundation, Arlington, VA. Earthquake Engineering Research Centers Program., April 11, 2007, 206 p.
- Identifying Number(s)
- MCEER-07-0003
- Abstract
- This research aims to extend the ductile end diaphragm concept used on steel bridges to make it applicable for bidirectional earthquake excitations, using unbonded braces as ductile fuses. Irregular (i.e. skewed) bridge superstructures are also covered to determine if the ductile diaphragm concept could be used in skewed bridges. Two retrofit schemes are investigated in detail to determine the best geometrical layout (to maximize the dissipated hysteretic energy) of the ductile diaphragms with unbonded brace end diaphragms. Closed form solutions are sought for practical design purposes. Behavioral characteristics of the proposed retrofit schemes are quantified with an emphasis on hysteretic energy dissipation. Results from numerical examples show that the bidirectional loading, loading ratio (or the assumed combination rule), and skew angle have a pronounced effect on the end diaphragm's inelastic behavior. Based on volumetric hysteretic energy dissipation, the effectiveness of the proposed retrofit schemes are compared under several loading cases for both non-skewed and skewed bridge superstructures.
- Keywords
- Seismic design; Bridges (Structures); Skewed bridges; Earthquake engineeting; Retrofitting; Energy dissipation devices; Bridge models; Loads (Forces); Numerical models; Steel superstructures