Implementation of MASH Ali Hangul, P.E. Tennessee Department of Transportation
Guardrail Standards
At The beginning of MASH
TXDOT research at TTI passed MASH using 36” barrier height 31” w-beam GR with 8 blackout tested for a small vehicle by TTI for TXDOT
Pooled Fund Study : “Placement of Guardrail on Slopes” 31” w-beam GR with 8 blackout tested for a small vehicle by TTI for TXDOT 31” w-beam GR in slope TTI completed for Roadside Safety Pooled Fund 6:1 6’ post 4:1 7’ post 3:1 8’ post 2:1 9’ post 1:1 11’ post Pooled Fund Study : “Placement of Guardrail on Slopes” Phase III: New Guardrail Design for Placement on 1H:1V Slopes
Updated Standard drawing
Updated Standard drawing
Terminals TL-3 Tangential GR end terminals (Proprietary items) Two models reevaluated per NCHRP 350 for 31” (Confusing for users) One new design evaluated per MASH for 31” (One point to consider, MASH does not require 31” installation height) Waiting for two additional manufacturers to have their products being evaluated. Than the Department can adoped MASH exclusively.
Downstream End Terminals Recently TTI completed a study for TX DOT
Downstream Terminal detail
TXDOT Standard
TDOT Standard Initial detail
Revised Standard, further adjusted wood post length
Currently no MASH evaluation (TL-2) is proposed for slotted flared terminal
Current Issue 31”Bridge parapet transition Working process Design and NCHRP Report 350 Finite Element Analysis of Stacked W-Beam Transition for 31-inch Guardrail (601721)
Currently the only alternative is adopting thrie beam transition detail developed by TXDOT
Buried in Back slope terminal anchor
Simulation completed for NCHRP 350 TL-3 at 31” further evaluation is needed for MASH
Tangential Guardrail End Terminals Initial revision did not address the special GR length as well as payment length
Revised to show terminal Payment length to 46’-10 ½”
Study has been done, needs FHWA Eligibility Letter
Concrete Bridge Rail/Median Barrier
TDOT Current Concrete Barrier Wall Standard
Roadside Safety Pooled Fund Program Research Problem Statement Future Work Roadside Safety Pooled Fund Program Research Problem Statement State: Texas Title: MASH Coordination effort Problem Statement: As we approach MASH implementation agreement sunset dates for NCHRP 350 devices many entities, individual state DOT’s, Pooled funds, and private industry, will be crash testing highway safety devices to MASH standards. Currently, DOT’s don’t have a reliable method to know what other DOT’s have tested and are working on testing. This environment of each state working in a vacuum is not conducive to planning and may lead duplicate efforts, wasted time and money. Objectives of the Study: The objective of the study is to create a database of MASH tested devices, proposed testing and DOT needs for MASH testing. The database should be accessible to all state DOT’s or at least a representative of each state. Also, a recommended procedure for updating the database should be part of the deliverable. Expected Benefits: The benefits of this project would be that it would provide State DOT’s the opportunity to better plan their tests, reduce the risk of duplicate efforts and provide an opportunity for collaboration between states on mutually beneficial projects. Description of the Proposed Feature to be Tested: (Be as detailed as possible. Include drawings and/or plans, if available.) The database could be a spreadsheet that is maintained by an individual and updated and emailed to contacts monthly, a website, spreadsheet or application that is accessible for edit to approved persons from each state, or any other format that would allow the information to be shared and updated. Estimated Cost (of the feature per linear foot installed): Total Estimated Cost of Crash Test: Contact Person: Chris Lindsey Telephone: 512-416-2750
Thank you ALI R. HANGUL P.E., CPESC| Assistant Director Headquarters Roadway Design and Office of Aerial Surveys James K. Polk Bldg, 13th Floor, 505 Deaderick St., Nashville, TN 37243 Phone No. 615-741-0840 ali.hangul@tn.gov tn.gov/tdot