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Side-mounted weak post MGS w-beam

State IN
Description Text

The SGR53 side-mounted weak-posted MGS w-beam was design to attach to a culvert.  Are the details also acceptable to use with a slab bridge?

Also are there min/max dimensions for how far apart the mounting brackets/threaded rods are?


Bridge Rails

Date April 8, 2024
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Attachment INDOT Bridge Rail.jpg Attachment Side mounted MGS TL-3.pdf

A few comments to address your questions.


  1. We did adapt this system to a bridge deck application for NDOT several years ago. Details are in the report link –
    1. The bridge deck design was developed for a 7” deck. It does not require upper and lower anchors like the culvert mounted system.
    2. This is the most efficient side-mounted connection we have to date.
  2. The original version of the system developed for bridge decks used a through bolt. This design was for an 8” deck. -
  3. TTI has used a top mounted version of this weak post bridge rail as well. I can find the report for that if you need it.
  4. We would not recommend moving the anchors on the culvert mounted system closer together to fit in a thinner bridge deck. This would change the moment arm for the socket anchorage and would increase the load on the upper tensile anchors. This is why we developed the alternative bridge deck connection for NDOT.


Let me know if you need anything else.



Date April 9, 2024
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