Been using the same load chart method for 15 years and just found out it's flawed

I was on a site in Denver last month, setting up a 250-ton crane for a bridge piece. My chart said we were good at 85 feet, 30 degrees. An old rigger I've known for years walked over, pointed at the outrigger pads, and said 'Your chart's lying, the ground here is soft as butter.' He was right. I'd been trusting the book numbers without thinking about ground pressure for over a decade. We had to move the crane 40 feet and use bigger mats. How many of you actually double-check the chart against the real ground conditions every single time?

2 comments

2 Comments

michaeladams1mo ago

Ever ask that old rigger what signs he looks for in the ground first? Before even pulling out the chart.

gonzalez.phoenix1mo ago

Signs he looks for in the ground" makes it sound like he's reading tea leaves or something. I mean, how much can you really tell from just looking at dirt? Seems a bit over the top.