Remember that big windstorm in Chicago back in 2015? I was on a job downtown and it changed how I think about load charts forever.

3 comments

3 Comments

Was that the one where the gusts hit 70? We had a tower crane on a high rise site that day. The chart said we were fine, but watching the load swing wild made it clear numbers don't tell the whole story. I started adding a big buffer for wind after that, no matter what the book says. You just can't trust a perfect forecast when you're that high up.

kai_webb9117d ago

Ever try a wind sock up there?

nathan10017d ago

Kai, a wind sock is a solid idea for a general read, but it's not enough for crane work. The problem is lag. By the time that sock whips straight out, the gust is already hitting your load. We use live anemometers up the tower and in the boom tip. Even then, like Felix said, you need that buffer. Seeing a load start to walk across the roof in a gust you didn't see coming changes how you read every chart after that.