I keep seeing these large rectangular structures on job sites they put in the ground.


I'm guessing something for strengthening the surface structures?

  • 3
    $\begingroup$ I believe this is a trench shield or steel trench box, which protects workers from cave ins while working on utilites $\endgroup$
    – depperm
    Commented Mar 5, 2020 at 17:37
  • 1
    $\begingroup$ Ahh!!! That's it! Thanks! If you put it as an answer, i'll mark it as such. $\endgroup$
    – v15
    Commented Mar 5, 2020 at 17:40
  • 3
    $\begingroup$ Yep. And despite them being required by OSHA (I think), you'll still come across an operation where they are not being used. Usually shows up on the evening news when a worker is buried due to a wall collapsing. $\endgroup$
    – SteveSh
    Commented Mar 5, 2020 at 17:41
  • $\begingroup$ I'm voting to close this question as off-topic because this isn't about home improvement. $\endgroup$ Commented Mar 6, 2020 at 2:24
  • $\begingroup$ Is there another meta site you can move this too? Looking at the views and up votes it appears to be useful information $\endgroup$
    – v15
    Commented Mar 6, 2020 at 2:28

2 Answers 2


It is a trench shield. It gets placed in a trench after the trench is dug to prevent workers from being hurt or killed in the event of a trench collapse.

enter image description here

This picture from GMC trench shield shows a partially collapsed trench with a shield installed that would protect the workers installing the blue brute pipe.

  • $\begingroup$ I remember 2 instances where a person lost his life due to that person going into or working in a trench where one of those supports was on the job but not used. One such accident happened at a job near Philadelphia, Pa. and one happened at a job site north of Pittsburgh, Pa. $\endgroup$
    – d.george
    Commented Mar 6, 2020 at 14:48

It is shoring for trenching work.

If a trench collapses on a worker the weight and force of the material will lead to crush injuries. Even if you are able to dig someone out from a collapse, crush injuries can lead to crush syndrome ending with kidney failure and death.

  • 4
    $\begingroup$ The primary risk in a trench collapse is simple suffocation. $\endgroup$
    – isherwood
    Commented Mar 5, 2020 at 18:03

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