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Vehicle crash barrier (W-beam or Thrie Beam)
2
thread507-462566 Forum Search FAQs Links MVPsForum
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(Structural)
(OP)
17 Jan 20 20:38Does anyone have experience using a AASHTO highway style vehicle barrier in a building? Specifically the W beam or Thrie-beam style bent shapes made from light-gage steel bolted to wide-flange beams.Example:The issue I have is that I cannot get these members to pencil out in flexure using the 6,000 lb load. Spans I have used 12'-6". Based on my research, it appears these are used to more deflect a vehicle back in the direction of travel rather than to withstand a direct impact.Would love to hear some feedback.
(Structural)
17 Jan 20 21:07I'm not overly familiar with AASHTO, but looking at chapter 13, Traffic Railing is defined as "Synonymous with vehicular railing; used as a bridge or structure mounted railing, rather than a guardrail or median barrier as in other publications."
I think the website you posted is more of a median barrier intended to slow or redirect traffic as you said.
The AASHTO design values seem to all be based on an angle of impact less than 90 degrees (since these are oriented parallel to the flow of traffic and things really have to go sideways for a straight on impact). So I'd be inclined to not use those values, except perhaps to take the vector sum of the transverse and longitudinal loads for the appropriate "test level" in chapter and appendix 13 to get a good head on equivalent static force.
2
STrctPono(Structural)
17 Jan 20 21:14These guardrails are not meant to remain elastic. Your best chance of getting the analysis to work out would be running an inelastic analysis or yield line analysis. I've attached the excerpt from the latest AASHTO (taken from MASH) that addresses this. Also, since you will most likely be mounting this guardrail to concrete?..... you will be interested in the last few pages that discuss analyze the concrete for breakout with that configuration. I've also attached the table in AASHTO that addresses the test level load values and how they are applied and at what height. It's a static pseudo load but it's not a point load. It's a distributed load. See Table A13.2-1 and Figure A13.2-1. 6,000 lbs is super low, even lower than the lowest test level of TL-1.Nowadays all barrier systems are crash tested and they don't load them at an orthogonal angle. Depending on the size of the truck and test level, it's typically between 15 and 25 degrees. Even the shapes for different concrete barriers need to be crash tested. You can't just come up with your own single slope face barrier. Each state either tests their own barrier systems or steals it from another state that invested the money to do the testing.
(Structural)
17 Jan 20 21:15Here's the other attachment.
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