|Principal Investigator(s) and Institution(s)
Ronald T. Eguchi, ImageCat, Inc.
Under Task 106-E-7.3.1 of FHWA/MCEER Project DTHF61-92-C-00106, the
methodology and beta version software for conducting a seismic risk
assessment (SRA) of highway systems (currently called REDARS) was
developed. Certain extensions are being considered to make the software
more adaptable to decision making. Ultimately, the software will be used
to improve the seismic design and construction of new facilities, the
seismic retrofit of existing facilities, and the development of
effective post-earthquake response and recovery strategies.
Prior to starting work on these extensions, however, it is desired to
have the existing methodology and software independently reviewed,
calibrated, and tested. The purpose of this task is therefore to perform
an in-depth review of the current REDARS methodology and
software. Specifically, the following objectives will be pursued in Year
2: a) test the usability of the program by implementing an example for a
new study area, e.g., Los Angeles, b) identify key program modules and
parameters by performing sensitivity studies, c) validate the
methodology by comparing the results of REDARS to actual
earthquake data, e.g., 1994 Northridge earthquake, and d) determine the
usability of the results by working with an end-user panel or group.
During Year 2, the following subtasks will be performed:
- SRA Review. The project team will complete its review of
the SRA methodology. Particular attention will be given to those
parameters and models that can be modified or replaced. Since one of
the tasks this year deals with the sensitivity of results to changes
in parameter values, it will be important to determine the extent to
which these models can modified.
- Implementation of REDARS Code. During this phase of the project,
we will install REDARS on our system for subsequent testing and
evaluation. We understand that the Beta version of the program will
be available for testing prior to July of 2000. We will implement
several simple examples, as well as install the Memphis Case study.
As part of this subtask, we will also test the completeness and
understandability of the Users Manual.
- Develop Input Data for Los Angeles Case Study. To implement
REDARS for Los Angeles,
compile data and information on local seismic hazards in the Los
Angeles area (including soil data), bridge information (including
bridge types, configurations, number of spans, etc.), highway
network data, and traffic flow information. In Year 1, the project
team collected damage and post-earthquake traffic information on the
1994 Northridge earthquake. These data will be used in the
sensitivity and validation studies.
- Conduct Sensitivity Studies. In Year 2, we will begin conducting
sensitivity studies in order to identify key parameters and modules.
The purpose of these sensitivity studies is to 1) identify the
effect that parameter uncertainties have on the final loss
estimation results, and 2) to identify possible simplifications in
the methodology to facilitate more rapid calculations of loss or
impact. In particular, we will focus on those simplifications that
will help to improve the modeling of post-earthquake traffic
patterns and levels. These sensitivity studies, which will focus on
Los Angeles, will be combined with similar studies for Memphis (see
task statement for B1-2).
- Conduct Validation Studies using Data from the 1994 Northridge and
1987 Whittier Narrows Earthquakes. We will begin the validation
process by developing the input required to run REDARS for two
southern California earthquakes: 1994 Northridge and 1987 Whittier
Narrows. The Northridge earthquake will test REDARS' ability to
identify changes in post-earthquake traffic patterns after a major
earthquake. The Whittier Narrows event will be important in ensuring
the programs reliability for a smaller and less damaging event. This
validation process will begin in Year 2 and will continue in Year 3.
- Conduct Workshop focused on End-User Needs. At the beginning of
Year 2, we will conduct an end-users workshop that will 1) introduce
the SRA methodology and the REDARS software program, 2) examine
addition performance measures, 3) identify ways in which loss
estimation methods can be used for the design and construction of
new facilities, the retrofit of existing facilities, and the
development of more effective post-earthquake response and recovery
strategies, and 4) identify a mechanism to involve end-users
throughout this research project. The results from this workshop
will help to define the requirements for a Decision-Guidance tool
(see task statement for B1-2).
- Technical report documenting the review of the SRA methodology.
- Technical report documenting the results of the sensitivity
- Interim report on the validation studies.
- Proceedings of the End-User workshop
Testing Beta version of the REDARS software program. Testing
preliminary versions of any software program can often be problematic.
To overcome this challenge and to ensure that this task stays on
schedule will require extensive interaction between the software program
developer, SSEC and the reviewer, ImageCat, Inc.