Logged in as: Public User

Thrie-beam connection to twin steel tube bridge railing

Question
State OH
Description Text

I believe you worked with our group on standard drawing
MGS-3.1.  From past e-mails, I see that she used Iowa’s standard drawing
as a template.  I looked at the Iowa website, but didn’t see a connection
detail like the one shown below.  This is the MGS thrie-beam connection to
twin steel tube bridge railing.  I received a call from a contractor
asking if the washers (highlighted below) are necessary.  Do you know if
this connection detail was based on research from Midwest Pooled Fund or
another state?  I would normally assume that the washers are necessary,
but this particular contractor does a large amount of work for us and his
question makes me wonder whether I’m missing something.



Thanks,



http://www.dot.state.oh.us/Divisions/Engineering/Roadway/DesignStandards/roadway/Standard%20Construct%20Drawings/MGS-3.1_7-18-2014.pdf



 

Keywords
  • Approach Guardrail Transitions
Other Keywords none
Date January 6, 2016
Attachment twin steel tube.jpg


Response
Response

This issue has come up in the past regarding the use of the washers underneath the end shoe and nested thrie beam attachment. We have been recommending that washers be used based on the size and length of the slots in the current thrie beam end shoe pieces. We have some concerns that the size of the slots in the end shoe might allow the nuts to pull through. TTI has been using washers as well based on similar concerns. I believe that they have been using rectangular washers, but I do not have the spec.

 

In our recent tests, we have been using 5/8” F844 washers on the backside of the end shoe. That has worked fine to date. These are more standard parts and are easier to obtain.

 

http://www.portlandbolt.com/products/washers/standard-flat/

 

Thanks

 

Date January 7, 2016
Attachment DSC_5094.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.