Saw a tower crane tip over in downtown Denver last spring - changed how I look at ground conditions now

It was a Liebherr 180 EC-H. The crew was setting it up on a new high rise site. Wind was fine that day, nobody was rushing. But the outrigger pad sank into some old fill dirt. Nobody checked the soil report close enough. The whole thing just went over slow. No one got hurt, but it was close. Now I wonder - do we trust the crane setup crew too much? Or should operators be double checking ground prep themselves before we start? What's your take on who owns that responsibility?

3 comments

3 Comments

wood.uma4d agoMost Upvoted

I mean you said it yourself - that outrigger pad sinking into old fill dirt was the whole story right there. So if I'm an operator arriving at a site, what am I even supposed to check that the setup crew hasn't already missed? Like, am I supposed to dig a test hole every time or just trust the stamped report? Feels like the crew owns the ground prep but the operator owns the final call if something looks off.

emma_baker614d ago

Old fill dirt is exactly the problem, and that stamped report only covers what they tested. But here's something people don't talk about enough - watch for any cracks in the ground around where you're setting up. I saw a guy once drop an outrigger on a site that looked solid, but there was this hairline crack running through the dirt. Turned out there was an old drainage pipe three feet down that collapsed under the load. You ever noticed how many operators just look at the pad itself instead of scanning the whole area for signs of settlement or buried stuff?

keith2744d ago

Emma's point about the hairline crack is something I see all the time now, not just on cranes. I was at a gas station last month and watched a semi back up over a patch of asphalt that looked fine, but a whole section just caved in where a storm drain had rotted out underneath. It's like that old train crash in Montana a few years back where the track looked perfect on top but the ground underneath had washed out from a beaver dam. We treat the surface like it tells the whole story when it almost never does. I think the operator has to own the final look because they're the one who's going to feel it when things go bad, but the crew should be digging test holes or at least probing that ground before anyone sets a rig on it. The problem is nobody wants to be the guy who slows down a 500k setup.