Seismic Vulnerability of the Highway System

Task B1-2: Support for Review of REDARS Seismic Risk Analysis Software and Evaluation of Multi-tiered Architecture Standards

Subject Area: Loss Estimation Methodologies
Research Year 2

Principal Investigator(s) and Institution(s)

Stuart D. Werner, Seismic Systems & Engineering Consultants


This task continues work to develop and improve loss estimation methods for highway systems, by building on the methodology for seismic risk analysis (SRA) of highway systems that was initiated under the FHWA Contract DTFH61-92-C-00106 (Project 106). During Research Year 2, this task will include: (a) continued support of the independent SRA review being carried out in Task B1-1; (b) sensitivity studies; and (c) software architecture assessment and planning. Subtask (c) has been elevated in importance as the California Department of Transportation (Caltrans) has now expressed interest in the REDARS software and is currently assessing its capabilities for possible implementation and evaluation. In order to run effectively, however, in a Caltrans-like environment, it may be critical to have the system ported to a client-server operational standard.


During Research Year 2, the following subtasks will be performed: 

  1. Support of SRA Review. The team that developed REDARS during FHWA Project 106 will continue to provide assistance to the reviewers of the software working under Task B1-1 to address questions that may arise, assist in their evaluation and assessment, and work with them in developing a software evaluation plan.
  2. Sensitivity Studies. During Year 2, work will begin on the use of models from the Research Year 1 demonstration SRA of the Shelby County, Tennessee highway system, in order to assess the sensitivity of the SRA results to variations in selected input and model parameters. Results from this two-year effort will be used together with parallel work being carried out under Task B1-1 for the Los Angeles, California highway system to: (a) establish priorities for further development of the various modules of the REDARS SRA methodology during future years of Project 094, and (b) assess the potential for future simplification of REDARS input data needs and SRA methodology.
  3. Software Development Planning. A three-tier software application is one in which the application and database reside on a server, and all processing of the programming takes place on a server. The user would have a client window on their PC on which they would enter information and review results; however the PC is a viewing tool only. During Year 2, we will investigate the feasibility of developing REDARS as a three-tier application by: (a) estimating costs and times required for this development effort and for validation of the resulting software; and (b) evaluating the benefits of this approach pertaining to computability, software maintenance, database integrity, programming, and costs. This planning effort will provide a basis for assessing whether REDARS should be developed as three-tier software during future years of this project.


  • Program plan for use in assessing feasibility of further development of REDARS into a three-tier application, and support to Caltrans during their review of the REDARS software application.
  • Technical report describing interim results of our sensitivity studies.
  • As-needed support of independent review of SRA methodology under Task B1-1, in response to any questions or requests for support that may arise.

Technical Challenges

The major challenges for Research Year 2 will be: (a) providing the necessary support for the SRA review under Task B1-1 within a fixed budget that can only be roughly estimated at this time; (b) the implementation of sensitivity studies to establish future research plans and priorities; and (c) the development of a program plan to assess future directions for further development of the REDARS software.


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