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From: Ronald K. Faller [mailto:rfaller1@unl.edu]

Sent: Wednesday, August 13, 2014 1:10 PM

To: Jewell, John R@DOT; Whitesel, David A@DOT

Cc: rfaller1@unl.edu

Subject: Bridge Rail

John and David:

I received an inquiry from one of our Pooled Fund Member
States (MnDOT) regarding a CALTRANS bridge railing, specifically B11-54. This
concrete parapet utilizes an 8-in. curb/sidewalk in advance of the 27-in. tall
vertical RC parapet. A tubular hand-railing is attached to the top of the
parapet. What is the height to top of hand-railing? Does the hand-railing
contribute to vehicle redirection in the PL-1 or TL-2 tests? Can I get a copy
of the test report as well. Thanks!

Ron,

Here is the detail for the handrail.  The bridge rail you are referring to is the Type 26 and it was never crash tested.  I believe it was grandfathered in as a TL-2 bridge rail a long time ago but I can't say exactly how that happened.  John Jewell may have more information.  That said, we have an ongoing project to test a (hopefully) TL-2 MASH-compliant version of that bridge rail, called the 732SW.  All the crash testing is complete on that project and I am currently finishing up the final report.  To qualify this bridge rail at TL-2, we conducted the pickup test at MASH TL-3.  In that test, it appears the handrail may contribute slightly to vehicle direction and rollover stability as the dynamic deflection of the handrail was approximately an inch.  As a side note, we also conducted a TL-3 small car test but had it fail due to high ridedown acceleration when the impact point was the sidewalk edge.  Essentially the sidewalk impact caused just enough flail space to be taken up such that the occupant impact occurred near the beginning of the impact with the barrier face, thus resulting in higher than expected ridedown accelerations.  It was an interesting phenomenon.  Because of this, FHWA concurred that we could use a TL-2  small car test to qualify the bridge rail at TL-2 so we also performed that test.  If you would like, I can send you a copy of the report when it is complete, which should be in the next month or two depending on how much time I can devote to it.  Please let me know if you would like any more information.

David Whitesel, P.E.

Roadside Safety Research Group

Office of Safety Innovation and Cooperative Research

Division of Research, Innovation and System Information

California Department of Transportation