Seismic performance and loss assessment

Sponsors: New Zealand Earthquake Commission (EQC), Tertiary Education Commission (TEC)

Collaborators: Rajesh Dhakal, Greg MacRae, Misko Cubrinovski, Dominic Lee (UC), Jack Baker (Stanford)

Postgraduate researchers: Sam McHattie, Trevor Yeow, Mohammad Koopaee

Seismic performance and loss assessment of the Fitzgerald Avenue twin bridges (Bradley et al. 2010).

Seismic performance and loss assessment methods combine (two or more of) seismic hazard, seismic response, damage fragility and damage consequences to allow quantification of seismic risk. As a result, such methods provide improved seismic performance metrics which can be used to understand and improve communication of seismic risk to non-technical stakeholders.

This research has focused on both the development of seismic performance and loss assessment methods, as well as applications to case study structures.

Specific contributions in terms of methodological developments include:

(i) Assessment of the accuracy of simplified performance and loss estimation methods (Bradley and Dhakal, 2008, Bradley and Lee, 2010);

(ii) Intensity measures for use in seismic performance assessment of soil-pile-structure systems (Bradley et al. 2009), and effect of intensity measure selection for prediction of spatially distributed seismic demands in a structure (Bradley et al. 2010a, 2010b);

(iii) Efficient numerical solution of the governing integral equations using "Magnitude-oriented Adaptive Quadrature" (Bradley et al. 2009);

(iv) Consideration of correlations between different structural components (Bradley and Lee, 2010);

(v) Consideration of epistemic uncertainties in seismic hazard (Bradley 2009) and component fragility (Bradley 2009) on seismic performance metrics; and

(vi) Application to high-rise structures (Bradley et al. 2009), and bridge-foundation-soil systems (Bradley et al. 2010).

SLAT: Seismic Loss Assessment Tool

A Fortran-based program is freely available which contains the above methodological developments is freely available. The download contains the exe files, source code, user manual and examples.

The program is currently being ported into Java and written using Object-oriented Programming in order to facilitate development from third parties. If you would like to help contribute to this initiative, please contact me.

Seismic performance and loss assessment of the Red Book building (Bradley et al. 2009).

Relevant Publications:

1. Bradley BA, Cubrinovski M, Dhakal RP, MacRae GA. Probabilistic seismic performance and loss assessment of a bridge-foundation-soil system. Soil Dynamics and Earthquake Engineering 2010. Vol. 30 No. 5, pp 395-411.
2. Bradley BA, Dhakal RP, Cubrinovski M, MacRae GA, Lee DS. Seismic loss estimation for efficient decision making. Bulletin of the New Zealand Society of Earthquake Engineering 2009, Vol 42 No. 2, pp 96-110.
3. Bradley BA, Dhakal RP, Cubrinovski M, MacRae GA. Prediction of spatially distributed seismic demands in specific structures: Structural response to loss estimation. Earthquake Engineering and Structural Dynamics. 2010. Vol. 39 No. 6, pp 591-513.
4. Bradley BA, Dhakal RP, Cubrinovski M, MacRae GA. Prediction of spatially distributed seismic demands in specific structures: Ground motion hazard and structural response. Earthquake Engineering and Structural Dynamics. 2010. Vol. 39 No. 5, pp 501-520.
1. Bradley BA. Epistemic uncertainties in component fragility functions. Earthquake Spectra 2010, Vol 26 No. 1, pp 41-62.
   1. Bradley BA, Lee DS. Component correlations in structure-specific seismic loss estimation. Earthquake Engineering and Structural Dynamics 2010, Vol 39 No. 3, pp 237-258.
2. Bradley BA, Lee DS. Accuracy of approximate methods of uncertainty propagation in seismic loss estimation. Structural Safety 2010, Vol 32 No. 1, pp 13-24.
   1. Bradley BA, Dhakal RP. Error estimation of closed form solution for annual frequency of structural collapse. Earthquake Engineering and Structural Dynamics 2008, Vol. 37 No. 15, pp 1721-1737.
3. Bradley BA. Seismic hazard epistemic uncertainty in the San Francisco bay area and its role in performance-based assessment. Earthquake Spectra 2009, Vol 25 No. 4, pp 733-753.
   1. Bradley BA, Cubrinovski M, Dhakal RP, MacRae GA. Intensity measures for the seismic response of pile foundations. Soil Dynamics and Earthquake Engineering 2009, Vol. 29 No. 6, pp 1046-1058.
4. Bradley BA, Lee DS, Broughton R, Price C. Efficient evaluation of performance-based earthquake engineering equations. Structural Safety 2009, Vol. 31 No. 1, pp 65-74.
   1. Bradley BA. The seismic demand hazard and importance of conditioning intensity measure. Earthquake Engineering and Structural Dynamics (in press).
5. Bradley BA, Design seismic demands from seismic response analyses: A probability-based approach. Earthquake Spectra 2011. Vol 27 No 1. pp 213-224.