1. GMSM Mission and Vision Jennie Watson-Lamprey October 29, 2007

2. Ground Motion Selection and Modification The results of nonlinear dynamic analyses are sensitive to the suite of input ground motions. There is no consensus as to the best method, thus the choice is largely subjective.

3. GMSM Mission To provide guidance to the engineering community on appropriate GMSM methods for nonlinear dynamic analyses.

4. GMSM Mission Identify an application for which the ground motions will be employed. Identify the goal of the application. Identify the candidate GMSM method. Develop an evaluation procedure. Compare the results of the analyses using the evaluation procedure.

5. 2006 Research Start with a simple case to develop our work plans. Typical California 4-story structure Deterministic earthquake scenario Common structural response parameter

6. 2006 Results

7. Large variability in median predictions Overestimation of median on average Taking nonlinear response into account in some way improved the estimates Variability of structural response was not accurately predicted

8. 2007 Research Focus on median predictions Additional structural models Same deterministic event Continue to interact with method developers as their methods change

9. 2007 Research Main analysis complete Some additional work necessary to finish conclusions PEER Report to come out next year

10. 2008 and Beyond Using the comparison method we developed to look at: –Ground motion inputs –Structural models –Analysis goals

11. 2008 and Beyond GMSM Vision: To serve as a resource for major research projects to address this key issue.