Determination of minimum height and lateral design load for MASH test level 4 bridge rails.

Details

• Creators:
  Sheikh, Nauman M. ; Bligh, Roger P. ; Ivev, Don L.
• Corporate Creators:
  Texas Transportation Institute
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office ; United States. Federal Highway Administration
• Subject/TRT Terms:
  Bridge Railings Bridge Railings--Crash Tests--Texas Bridge Superstructures Guardrails Highway Safety Impact Tests Mechanical Tests Transportation Safety
• Publication/ Report Number:
  FHWA/TX-12/9-1002-5 ; Test Report 9-1002-5
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Test report; Aug. 2009¿Aug. 2010.
• Corporate Publisher:
  Texas Transportation Institute
• Abstract:
  The Manual for Assessing Safety Hardware (MASH) prescribes higher design vehicle impact speed and mass for test level 4 barriers compared to its predecessor National Cooperative Highway Research Program (NCHRP) Report 350. This has resulted in a 56 percent increase in impact severity for test level 4. The current American Association of State Highway Transportation Officials (AASHTO) Load and Resistance Factor Design (LRFD) Bridge Specifications require test level 4 bridge rails to have a minimum rail height of 32 inches and to be designed for a 54-kip lateral load. These requirements were based on NCHRP Report 350 impact conditions and need to be revised for the higher impact severity under MASH. A recent MASH test 4-21 with a 32-inch tall New Jersey profile rigid concrete barrier, which performed acceptably under NCHRP Report 350 TL-4, resulted in the vehicle rolling over the barrier.
  
  This research had the objectives of determining the minimum rail height and lateral design impact load for MASH test level 4 bridge rails. Using parametric finite element analysis and subsequent crash testing, the researchers determined the minimum recommended rail height for MASH TL-4 impact conditions to be 36 inches. Lateral design impact load for MASH TL-4 test conditions was determined to be 80 kips.
  
  A 36-inch tall Single Slope Traffic Rail (SSTR) that meets these rail height and lateral load capacity requirements was crash tested. The 36-inch tall SSTR successfully contained and redirected the impacting vehicle. Details of the simulation analysis, barrier design, full-scale crash testing, and crash test results are presented in this report.
  
  
• Format:
  PDF
• Funding:
  Project 9-1002
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:f1af70d1413fbae4dc20545dcafdb0d8e9ab739b28022b466f0c56c61a6c182678b4d6c97913bf35db4c4e1592f538734746036c04549a2380c80b465b435cfa
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/23779/dot_23779_DS1.pdf
• File Type:
  [PDF - 7.00 MB ]