Ground Motion Studies for Transporation Systems

Ground Motion Studies for Transportation Systems

Project # NCTRJB

Research Team

  • Jack Baker, Professor of Structural Engineering, Stanford University (PI)
  • Nirmal Jayaram, Graduate Student, Stanford University
  • Shrey Shahi, Graduate Student, Stanford University

Research Abstract

This project contains three subsets of objectives related to ground motion selection and scaling for transportation projects.

Objective 1, Ground Motion Selection, will consist of selecting a versatile set of ground motions for the TSRP program, to enable researchers to perform a variety of studies while still using a standardized set of ground motions.

To maximize the value of the ground motions selected, Objective 2, Guidance for Use of Ground Motions, will be conducted. These activities focus on enabling users to perform useful analyses with this ground motion set, which contains several new features that researchers will not be experienced in utilizing. The techniques will be demonstrated using example analyses of simple bilinear SDOF’s, to transparently illustrate the procedures in a situation where the audience can intuitively predict resulting responses.

Incremental Dynamic Analysis (IDA) has become a popular tool for use in Performance Based Earthquake Engineering (PBEE), to quantify the relationship between ground motion intensity measure (IM) and structural response. A notable shortcoming of this approach, however, is that the input ground motions are considered to be identical at all IM levels, while probabilistic seismic hazard analysis (PSHA) clearly show that ground motion properties (such as causal magnitude and spectral shape) change as the IM changes. Objective 3 of this project, Demonstration of Adaptive Incremental Dynamic Analysis, will improve current IDA methods, to account for the fact that these grounmotion properties change with the IM.

Research Outcomes

The following files document selected ground motions for use in the PEER transportation systems research program.

Documentation

Set #1a: Broad-band ground motions (M = 7, R = 10 km, soil site)

See the report above for background regarding the selection of these ground motions.

Set #1b: Broad-band ground motions (M = 6, R = 25 km, soil site)

See the report above for background regarding the selection of these ground motions.

Set #2: Broad-band ground motions (M = 7, R = 10 km, rock site)

See the report above for background regarding the selection of these ground motions.

Set #3: Pulse-like ground motions

See the report above for background regarding the selection of these ground motions. Further information on the technique used to identify these ground motions is available here.

Set #4: Site-specific ground motions for Oakland

This set of ground motions consists of ground motions selected to match the uniform hazard spectrum and associated causal events for a site in Oakland, California. Forty ground motions are provided to represent the ground motion hazard at each of three hazard levels (2%, 10% and 50% probabilities of exceedance in 50 years).

Presentations and other

The following are presentations given in the process of developing these ground motions

Research Impact

Ground motion selection is a topic of growing concern in practice, due to the growing use of nonlinear dynamic analysis (see, e.g. SEAONC’s recently initiated Seismology Subcommittee on Ground Motions). The results from this project may thus be a useful resource to the growing number of practitioners with interest in selecting and utilizing ground motions for analysis.

PEER Center - 325 Davis Hall, University of California, Berkeley, CA 94720-1792 -