Project Title/ID Number Database and Acceptance Criteria for Column Tests—5282002
Start/End Dates 10/1/02—9/30/03
Project Leader Marc Eberhard (UW/Faculty)
Team Members Mike Berry (UW/Grad Student), Haili Camarillo (UW/Grad Student)
Project goals and objectives

The goal of this project is to develop and calibrate tools for assessing reinforced concrete column seismic performance, including data and models for both seismically conforming (ductile) and non-conforming (brittle) columns.

Role of this project in supporting PEER’s vision

PEER's mission is to "develop, validate and disseminate performance-based seismic-design technologies." This mission has many facets, but one important step is to relate deformation demands placed on structural members with the likelihood of reaching particular levels of damage. For example, at a particular level of deformation, what is the likelihood that the reinforcing bars in a column will have buckled? This project provides the data and tools necessary to construct this link for reinforced concrete columns, one of the most vulnerable and critical structural components of building and bridges.

Methodology employed
  1. Continue to expand the scope of existing PEER column database, which was developed in years 1-5. This database will provide the basis with which to evaluate seismic design and assessment tools. The online database can be accessed at
  2. Develop and apply performance models to relate numerical data from simulation models to damage states that represent column performance in the PEER PBEE methodology. In particular, we will select, calibrate, exercise and validate OpenSees models for columns in collaboration with Professors Fenves, Fillippou and Deierlein.
  3. Investigate whether and how accounting for the effects of cumulative deformation will improve the accuracy of estimates of column damage.
    Implement these models as part of the I-880 bridge testbed. The column performance models will incorporate uncertainties and inaccuracies in column behavior and be able to track the effects of these factors through the analysis.
Brief description of past year’s accomplishments and more detail on expected Year 6 accomplishments

The size and scope of the database have been expanded during the past year. Most importantly, the online database not only provides test properties and digital, force-deflection histories, it also now provides the peak level of column deformation preceding the observation of each level of damage. The database is available at

A series of non-dimensional measures of column deformation (drift ratio, displacement ductility, plastic rotation, nominal compressive strain and nominal tensile strain) have been evaluated to determine the suitability for predicting the onset of spalling and bar buckling.

For each of these measures of deformation, methodologies have been developed and the accuracy of each methodology has been evaluated statistically. For example, the displacement at onset of bar buckling, buckle, can be estimated as follows:


  • k is equal to 50 for rectangular-reinforced concrete columns and 150 for spiral-reinforced columns
  • L: length of column to point of inflection
  • P/Agf'c : axial-load ratio
  • : transverse reinforcement ratio
  •  fytrans : yield strength of the transverse reinforcement
  •  f'c : concrete compressive cylinder strength

Figure 1. Typical Fragility Curve

Larger View



For each model, fragility curves have been developed, such as the one shown in Figure 1.

During Year 6, damage models will be developed for the OPENSEES simulation models. The potential of accounting for deformation history will also be investigated.

Other similar work being conducted within and outside PEER and how this project differs

This work does not duplicate research performed by others, but it does depend on extensive interaction with other PEER researchers.

Plans for Year 7 if this project is expected to be continued

Once the models have been calibrated for columns, it will be necessary to integrate the damage estimates into analyses of more complex structures. In such structures, it will be necessary to distinguish between model inaccuracy and inherent variability, in order to large numbers of columns (to what extent are individual assessments of individual columns independent of assessments of other columns in the same structure?)

Describe any instances where you are aware that your results have been used in industry

Fragility curves were provided to CALTRANS.

Expected milestones
  • June 2003 - PEER report that describes current models based on overall deformation.
  • June 2004 - PEER report that describes OPENSEES damage models and their accuracy.

Prediction models and accuracy statistics for development of damage in reinforced concrete columns.