Seismic Demands for Performance-Based Design Bridges

Principal Investigator: Bozidar Stojadinovic
Graduate Student: Kevin Mackie
Project ID: 3122000



OBJECTIVE & IMPACT

          The goal of this project is to frame performance-based design of straight short- and medium-span
          bridges in a design space defined  by  unconditional probabilities of exceedance of measures  of
          bridge performance.  The results of this project will contribute to  better understanding of the
          demand issues critical  to  performance-based  design of short- and medium-span bridges.   These
          results,  and  the results  of  other  PEER projects  focused  on capacity issues,  will make it
          possible to formulate a consistent performance-based bridge design procedure.          
          

PROJECT DESCRIPTION

      1.  Collect a suite of approximately 1500 earthquake ground motion records representative of a typical
          site in California  (near-  and  far-field records  with  various directivity and soil  profiles).
      2.  Identify bridge parameters, such as the number  and  type of joints  and  hinges, length of seats,
          number and height of columns,  and severity of skew.    Identify bridge performance measures, such
          as drift, curvature or shear distortion of columns, hinge rotations or seat motions.
      3.  Make a  3-dimensional parametric model of a bridge in OpenSEES,  using realistic non-linear models
          for bridge  components expected to incur damage  (such as columns or hinges)  and elastic or rigid
          models for bridge components expected to remain undamaged (such as bridge deck).
      4.  Choose a baseline set of bridge parameters,  and identify a number of variations from the baseline
          configuration.  The total number of different parametric bridge types should not exceed 15.
      5.  Perform a series of simulation studies.   For each model representing an instantiation of a bridge
          in the space of bridge parameters, run dynamic analysis for the suite of ground motions.
      6.  For each simulation study, compute the probability of exceedance of measures of bridge performance
          and construct bridge performance design curves in the design space.
      7.  Across a set of simulations,  extract the values of measures of bridge performance associated with
          characteristic of ground motion and construct bridge performance sensitivity curves.
      8.  Define bridge performance objective  curves and perform trial  designs to compare with the current
          design methods.
     

PROJECT DELIVERABLES

      1.  Project database.
      2.  Code for data exchange between OpenSEES and project database.
      3.  Unconditional Probability curves
      4.  Bridge performance objective curves
      5.  Final report and project web page
     

RETURN