Analysis of UCS by OpenSees

1
Analysis of UCSby OpenSees

• GSR Tae-Hyung Lee
• PI Khalid M. Mosalam
• May 23rd, 2002 Meeting at RFS

2
Objectives

• Conduct and verify a 2-D nonlinear time history
  analysis of UCS using OpenSees
• Develop floor responses to be utilized for the
  UCB and UCI shake table tests of the building
  contents
• Assess the importance of the different sources of
  uncertanties on the structural response
• Extend investigation to 3-D modeling including
  multi-directional ground motion

3
Current Status

• 2-D structural model completed for the UCS
  building
• Time history results (as absolute and relative
  floor displacements and accelerations and
  mid-points of all floors) are available for two
  levels of seismic hazard (50 and 10 in 50
  years)
• Similar results will be available for the third
  level of seismic hazard (2 in 50 years) by the
  end of July.

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Future Tasks

• 1) Verification
• A similar shear wall building where response data
  are available will be analyzed using the same
  modeling approach in OpenSees
• An example is the 9 story Robert A. Millikan
  Library Building at Caltech McVerry 1979

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Future Tasks (Cont.)

• 2) Assess Importance of Uncertainties
• The following five sources will be considered
• Spectral acceleration
• Mass
• Damping
• Force-deformation characteristics of the
  different elements, e.g. in terms of
  moment-curvature relations
• Soil/foundation properties

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Future Tasks (Cont.)

• 2) Assess Importance of Uncertainties (Cont.)
• The objective is to conduct similar study to that
  of (Porter et al. 2002, Earthquake Spectra) with
  focus on structural response parameters (rather
  than costs) and their sensitivity to modeling
  issues and input intensities.
• The importance of uncertainties will be assessed
  by developing a tornado diagram using the idea
  of swing estimation.

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Future Tasks (Cont.)

• A methodology has been developed using SFEM to
  generate probabilistic moment-curvature or
  interaction diagrams of RC elements Lee and
  Mosalam, 2002, Computers and Structures

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Future Tasks (Cont.)

• Several verification studies were conducted

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Future Tasks (Cont.)

• Some results of interaction diagrams

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Future Tasks (Cont.)

• 3) Extension to 3-D
• Modeling structural elements in longitudinal as
  well as transverse direction.
• Subject the building to simultaneous components
  of the ground motions.
• Investigate variations of floor response
  parameters within the floor space.