|Logged in as: Public User|
We have a request from the district to narrow the w beam
|Other Keywords||Cable Barrier|
|Date||February 12, 2015|
You are correct that we have tested two versions of the cable to W-beam transition system. The first test was conducted using the standard low-tension cable system transitioning to G4(1S) guardrail. The original cable to W-bean transition was tested with both a BCT end terminal and a the second test used a FLEAT end terminal. The cable heights for the original system used a 27" top cable height with 3" cable spacing. This cable height and spacing correlated well with the W-beam barrier height used in the design and allowed the top cable to be run along the top of the W-beam and the bottom two cables to be run along the bottom of the W-beam as they were transitioned from one system to another.
In both tested systems, the terminals were offset 4’ laterally from the cable barrier. For both systems the testing of the 2000P vehicle showed the potential for vehicle instability when the system was impacted such that the vehicle contacted the terminal end and the cable system simultaneously. Thus, there is concern that moving the terminal ends closer to the cable barrier may increase the vehicle instability further. In addition, the vehicle could deflect the cable system ahead of the terminal end allow the vehicle to get behind the end of the terminal at the shorter offset. This may further degrade the system performance. As such, we have allowed the end terminal systems to be extended to larger offsets in the past, but we have not allowed shorter offsets as we believe that they would potentially adversely affect the transition.
Let me know if you need anything else.
|Date||February 13, 2015|
130 Whittier Research Center
2200 Vine Street
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