View Q&A

MwRSF recommends that there is at least 7 half post spacing with normal post embedment and 2 ft of flat grading behind the post.

Could longer posts at half post spacing with the grade break at the back of the post be use (i.e. ? TRP-03-452-24 Evaluation of the MGS with Half Post Spacing and 7-ft Posts Adjacent to Slope) instead of the recommended installation in blue?

I think that approach has potential in terms of the system stiffness. For example, in the current research effort to examine the MGS long span adjacent to 2:1 slope, we are using a similar approach by using longer posts adjacent to the unsupported span.

Similarly, if we look at the previous strong post culvert attached post testing with ½ post spacing, we found a dynamic deflection of 29.6” and a working width of 50.8”. The MGS on 2:1 slope with ½ post spacing and 7’ posts that we tested had a dynamic deflection of 27.2” and a working width of 47.7”. These values are very similar and would suggest that the 7’ posts at half post spacing would be reasonable adjacent to the strong post on culvert installation.

One would need to consider the potential for snag on the exposed culvert if it extended above the grading/slope. Additionally, transition guidance provided for the MGS on 2:1 slope with ½ post spacing and 7’ posts to standard MGS would need to be utilized at some point in the system.

Thanks!