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The National Academies

NCHRP 22-35 [Active]

Evaluation of Bridge Rail Systems to Confirm AASHTO MASH Compliance

  Project Data
Funds: $500,000
Staff Responsibility: Waseem Dekelbab
Research Agency: Texas A&M Transportation Institute
Principal Investigator: Mr. William Williams
Effective Date: 6/1/2018
Completion Date: 6/30/2021

BACKGROUND
 
The American Association of State Highway and Transportation Officials (AASHTO) Manual for Assessing Safety Hardware (MASH) is the latest in a series of documents that provides guidance on testing and evaluation of roadside safety features. This document, initially published in 2009 and updated in 2016, represents a comprehensive update to crash test and evaluation procedures to reflect changes in the vehicle fleet, operating conditions, and roadside safety knowledge and technology. It superseded NCHRP Report 350: Recommended Procedures for the Safety Performance Evaluation of Highway Features.
 
The AASHTO Technical Committee on Roadside Safety (TCRS) and the Federal Highway Administration (FHWA) have adopted a new MASH implementation plan that has compliance dates for installing MASH hardware that differ by hardware category. After December 31, 2019, all new installations of bridge rails on the NHS must have been successfully evaluated according to the 2016 edition of MASH. Similar to NCHRP Report 350, MASH defines six test levels for longitudinal barriers. With respect to AASHTO LRFD Bridge Design Specifications, each test level places an increasing level of demand on the structural capacity of a barrier system. There is a need to evaluate the most common non-proprietary bridge rail systems used throughout the states to determine the level of evaluation required to demonstrate MASH compliance.
 
OBJECTIVE
 
The objective of this research is to update the AASHTO LRFD Bridge Design Specifications and the AASHTO Roadside Design Guide for bridge rail geometric design for AASHTO MASH. At a minimum, the research should include crash simulation and crash testing of the bridge railing systems that were found not satisfactory for the MASH equivalent test levels as documented in the NCHRP 20-07/ Task 395, "MASH Equivalency of NCHRP 350-Approved Bridge Railings".
 
Accomplishment of the project objective will require at least the following tasks.
 
TASKS
 
PHASE I—Planning
 
Task 1.  Review the report prepared under NCHRP Project 20-07/Task 395 (see Special Note A).
 
Task 2. Propose analytical and testing programs, to be executed in Phases II and III, to achieve the project objective. The analytical program should be designed using LSDYNA Finite Element Analysis (FEA) computer simulation. The testing program may include full scale crash testing and component testing.
 
Task 3.  Prepare Interim Report No. 1 that documents the results of Tasks 1 and 2 and provides an updated work plan for the remainder of the project. This report is due no later than 3 months after the contract award. The updated plan must describe the process and rationale for the work proposed for Phases II through IV.
 
PHASE II—Analytical Program
 
Task 4. Execute the analytical program according to the approved Interim Report No.1.
 
Task 5.  Finalize the testing program work plan including a matrix of railing systems to be tested. Describe how the testing results will be utilized to achieve the research objective.
 
Task 6.  Identify areas of the AASHTO LRFD Bridge Design Specifications and the AASHTO Roadside Design Guide that will be modified.
 
Task 7.  Prepare Interim Report No. 2 that documents the results of Tasks 4 through 6 and provides an updated work plan for the remainder of the project. This report is due no later than 12 months after approval of Phase I. The updated plan must describe the work proposed for Phases III and IV.
 
PHASE III—Testing Program
 
Task 8.  Execute the testing program according to the approved Interim Report No.2.
 
Task 9.  Validate the analytical program based on the testing results and update accordingly.
 
Task 10. Prepare Interim Report No. 3 that documents the results of Tasks 8 and 9 no later than 12 months after approval of Phase II.
 
PHASE IV—Final Products
 
Task 11. Develop the draft proposed AASHTO modifications based on the research results including barrier hardware system template similar to the AASHTO Guide to Standardized Highway Barrier Hardware according to the approved Interim Report No.3. The draft proposed AASHTO modifications are due no later than 3 months after approval of Phase III.
 
Task 12. Prepare final deliverables including: (1) the proposed AASHTO modifications that reflect consideration of the panel’s review comments, (2) a final report that documents the entire research effort, and (3) a stand-alone technical memorandum titled “Implementation of Research Findings and Products.” See Special Note E for additional information.
 
STATUS: Research in progress

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