Just read the OSHA report on crane tip-overs from last year and the main cause shocked me
I was looking at the 2023 OSHA fatality and catastrophe summaries online. They said over 70% of mobile crane tip-overs were due to soft ground or outrigger setup failures, not high winds or overloading like I thought. The report specifically called out a case in Tampa where the ground looked solid but gave way under full load. Has anyone else had a close call with ground conditions that seemed okay at first?
Wow, that's exactly it. Like @caseyf32 said, it's never just dirt, there's always something buried. I mean, even a washed-out trench from old rain or a layer of fill dirt that seems packed can just collapse. The Tampa case is basically the same story as a hidden tank, just different junk under the surface. It makes you wonder how many sites get a quick look and a "yeah it's fine" without any real testing.
That "hidden septic tank" detail is the real problem. Someone didn't do their job marking underground utilities before the crane rolled in. This is a major safety failure, not just bad luck.
But what about when the ground is tested and still fails? @angela_robinson mentions fill dirt, and that's the real killer. You can do a probe test and get a decent reading, but that only tells you about the top few feet. I've seen a crane punch right through a compacted gravel pad because there was an old, rotten timber mat buried from a job twenty years prior. It turned to mush under the point load. Sometimes the history of the site matters more than the current surface.