The National Academies

NCHRP 20-123(16) [Pending]

Roadmap for the Transformation to Computer Simulation-Based Assessment of Bridge Railings
[ NCHRP 20-123 (Support for AASHTO Committees and Councils) ]

  Project Data
Funds: $150,000
Contract Time: 16 months
Staff Responsibility: Ahmad Abu Hawash
Comments: A research agency has been selected for the project. The contracting process is underway.


The American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) 2nd edition is the latest in a series of documents that provide guidance on testing and evaluating roadside safety features. Implementing MASH has been a challenging mission for departments of transportation (DOTs). Implementing uniform guidelines has cost the nation tens of millions of dollars. DOTs and other transportation agencies need a roadmap to accommodate future transformations, such as the introduction of electrical vehicles and changes in MASH requirements, in a timely and more cost-effective manner. One of the most expensive and time-consuming pieces of the current process is building full-scale test sections and performing the actual crash tests. Often, multiple crash tests are required for a particular solution. Computer simulations are currently used in association with full-scale crash testing. There is a need for a safe and cost-effective tool for compliance assessment of bridge rails and bridge rail transitions.


The objectives of this research are to (1) evaluate the capability of existing numerical simulations tools in capturing the performance of bridge rails and rail transition systems and (2) develop a roadmap to implement using computer simulations for the compliance assessment of bridge rails and rail transition systems.

At a minimum, the roadmap must address, discuss, or identify (1) the current state-of-the-art practices in computer crash-testing simulations and the knowledge gaps, (2) quality assurance (QA)/quality control (QC) procedures for validating the computer simulation models, (3) the limitations of crash simulations, (4) the types and magnitudes of changes that trigger model updates, (5) the concept of using notional vehicles, and (6) research that will need to be pursued to implement the roadmap.

 Accomplishment of the project objectives will require at least the following tasks.


 PHASE I—Planning

Task 1.  Conduct a comprehensive literature review of relevant research and the current state of practice related to crash-testing bridge railing and bridge railing transition simulations and modeling. Include published and unpublished research conducted through the NCHRP, the Federal Highway Administration (FHWA), and other national, international, state, and pooled-fund sponsored research.

Task 2.  Synthesize Task 1 to identify the knowledge gaps in computer crash-testing simulations.

Task 3.  Propose a table of contents and format for the roadmap to achieve the research objectives. The roadmap will be fully developed in Phase II.

Task 4.  Propose a plan for industry and stakeholder outreach. Outreach shall be accomplished via a survey and a virtual workshop. The project panel should participate in the workshop.

Task 5.  Prepare an interim report that documents Tasks 1 through 4 and provides an updated work plan for the remainder of the research no later than 4 months after contract award. The updated work plan must describe the process and rationale for the work proposed for Phase II.


PHASE II—Road Map Development and Final Products

Task 6.  Develop the roadmap according to the approved interim report. At a minimum, the roadmap shall include:

  • Recommended steps to evolve from the current process for assessing the safety of bridge railing systems to the future state where full-scale crash testing may not be required,
  • An evaluation of federal and state regulations and specifications to allow compliance assessment without full-scale crash testing,
  • A discussion of stochastic/probabilistic methods for using computer simulations,
  • Recommendations for establishing a sustainable national clearinghouse for crash-testing data and models,
  • Discussion on the reliability of the computer simulations for the various bridge rail types with similar features,
  • QA/QC procedures for validating the computer simulation models,
  • Identification of limitations of crash simulations, and
  • Identification of additional areas of research needs.

Task 7. Conduct the virtual outreach workshop to obtain feedback on the roadmap. Prepare a technical memorandum that summarizes the workshop comments and lists proposed modifications to the roadmap for review and approval. Present findings from the technical memorandum to NCHRP at an online meeting. NCHRP approval of the memorandum must be obtained before work on remaining tasks begins. 

Task 8. Modify the roadmap based on the comments received in Task 7.

Task 9. Submit the final deliverables, including (1) the roadmap, (2) a final report that documents the entire research effort, and (3) a stand-alone technical memorandum titled “Implementation of Research Findings and Products.” 

The draft final deliverables are due no later than 8 months after approval of Phase I.


STATUS: A research agency has been selected for the project.  The contracting process is underway.

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