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what is the purpose of beam guard in the photo attached

Question
State	WI
Description Text	The RDG indicates that the guardrail shown on the attached file should be used near a short radius system. Any idea on why?

System Performance Evaluation

System Types

Applications
Bullnose Systems

System Features

Date July 1, 2015
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Attachment Doc5.docx

Response
Response (active)	I would assume that the guardrail shown upstream of the short-radius system in the attached figure is based on two related concerns. 1. All previously developed and tested short-radius systems have focus only on impact locations ranging from the center of the nose of the system and towards the primary roadway. Thus, the behavior of the system farther up on the secondary roadway is unknown. 2. Based on potential vehicle trajectories and runout length calculations, current short-radius systems may potentially be insufficient to shield the range of potential impacts. Placement of the additional barrier on the upstream side of the primary roadway limits the potential for these concerns. We have currently been working on a research project for NDOR to develop a treatment for intersecting roadways that better addresses the hazard area and has significantly higher capture capabilities. The Phase I report for that should be out this month and Phase II started July 1.

Response

Response
(active)

I would assume that the guardrail shown upstream of the short-radius system in the attached figure is based on two related concerns.

1. All previously developed and tested short-radius systems have focus only on impact locations ranging from the center of the nose of the system and towards the primary roadway. Thus, the behavior of the system farther up on the secondary roadway is unknown.

2. Based on potential vehicle trajectories and runout length calculations, current short-radius systems may potentially be insufficient to shield the range of potential impacts.

Placement of the additional barrier on the upstream side of the primary roadway limits the potential for these concerns. We have currently been working on a research project for NDOR to develop a treatment for intersecting roadways that better addresses the hazard area and has significantly higher capture capabilities. The Phase I report for that should be out this month and Phase II started July 1.

Date July 2, 2015
Previous Views (92) Favorites (0)