Logged in as: Public User

Guardrail Transition to a Bridge

Question
State KS
Description Text

We have a guard fence transition to a bridge that was recently hit.  This will be repaired per our maintenance policy.

 

My question is:

    1.    Can we use double blockouts in the portion where the curb is in front of the guard fence for the full length of the guard fence to bridge rail transition section?  How many posts can have more than one blockout and is there a limit, i.e. some may want to use three blocks on several posts.  I am looking into the height of the bridge rail to see if we can get thrie beam on it.

Keywords
  • Guardrail
Other Keywords none
Date September 5, 2006
Attachment DSC00006.JPG
Attachment DSC00005.JPG
Attachment DSC00004.JPG
Attachment DSC00003.JPG
Attachment DSC00002.JPG
Attachment DSC00001.JPG


Response
Response

I have reviewed the photos you sent and I believe we can retrofit your installation to improve it significantly. I have attached a schematic of our proposed modifications. We are basically proposing that you blockout the existing system using 24" deep spacer blocks (basically three standard 8" deep blocks in series). We have used 16" blocks on several systems in the past with no problems and we believe that 24" of spacer block is okay as well. We are also recommending that you replace the first 12'-6" section of w-beam with nested 12-gauge thrie beam. Then a W-thrie transition section would be placed between the nested thrie and the standard w-beam. This layout would make you installation very similar to the Iowa transition developed by the Pooled Fund and would increase the safety of the installation greatly. After the W-thrie transition section, the spacer blocks could be reduced incrementally to taper the w-beam to meet the existing installation.

Date September 7, 2006
Attachment trans.jpg


Contact Us:
130 Whittier Research Center
2200 Vine Street
Lincoln, NE 68583-0853
(402) 472-0965
Email: mwrsf@unl.edu
Disclaimer:
The information contained on the Midwest Roadside Safety Facility (MwRSF) website is subject to change without prior notice. The University of Nebraska and the MwRSF is not responsible or liable, directly or indirectly, for any damage or loss caused or alleged to be caused by or in connection with the use or misuse of or reliance upon any such content, goods, or services available on this site.