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The Minnesota DOT is looking to implement standards for anchoring temporary barrier over bridge expansion joints. Early discussions have led us to reviewing 2 standards used by the Kansas DOT (attached). The first drawing is for situations where the anticipated movement at the expansion joint is less than 1.5". We like this standard and are wondering if you know of its history or use by other states? Do you have any recommendations or suggestions regarding anchoring barriers over expansion joints or know of any other examples that have been crash tested?
The second attachment was developed by John Jones at the Kansas DOT. Even though the barrier is only rated to TL-3, John designed the wire rope that runs through the barriers to take a TL-4 load, independent of any other connections. He also designed the 1" dowel between the barriers to take a TL-4 load without any other support. Lastly, he designed the steel cover plate to take a TL-4 load without any support from the wire rope or 1" dowel. Hence, this design should be very conservative as each "link" was independently designed for TL-4. He indicated the system has NOT been crash tested. Are you aware of any other state details or crash tested systems that can accommodate more than 1.5"? John thought this system could be used over expansion joints with movement up to 4-5 inches.
Any thoughts, recommendations, or references to other state standards or details would be greatly appreciated.
|Date||April 7, 2012|
|Attachment||Kansas Less than 1.5 inch movement rd622b.pdf|
|Attachment||Kansas More than 1.5 inch movement rd622c.pdf|
We are aware that the KsDOT developed a design detail for providing temporary positive protection across an expansion joint utilizing a pinned, F-shape TCB in combination with dowel bars, interior cables, and a steel cap plate. We were involved with some of the initial discussions but did not conduct any type of analysis. Instead, it was my understanding that the KsDOT Bridge Division conducted an FEA analysis to verify the structural capacity and investigate plate deformations within the cap plate. I believe that the KsDOT has implemented this system in a couple of locations over the last several years but have not seen photographs of the system nor feedback on how it worked.
A couple of years ago, the MoDOT also investigated the KsDOT system for use in a particular application. Joe Jones of MoDOT was involved in this discussion. Since I do not know what transpired from this situation, you may want to contact Joe directly to further investigate whether the steel cap plate and other KsDOT details were ever implemented. I have provided an electronic pdf copy of the prior email correspondence on this issue that occurred between MwRSF, KsDOT, and MoDOT. Additional details on gaps and lengths were provided by KsDOT.
Over the years, the Florida DOT has implemented significant details for the F-shape concrete barrier segments into their state standards. I would suggest that you review their many details which may provide additional insight for spanning expansion joints with pinned TCBs. MwRSF has provided review and comment on many of their TCB details when asked.
Finally, I am not aware of any other details or anchored temporary barrier systems that have specifically accommodated expansion joints/gaps.
Please let us know if you have any further questions or comments regarding the limited information provided above. I am sorry that we could not be of more help on this matter.
|Date||April 13, 2012|
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