Minor Cantalever Issue

[Marcel R. Cyr]

Originally Posted by jpope

Did you take that picture Marcel? Jumping towers was always the most dangerous part of crane operation, but this looks like a "self-raising" tower. Is that so?

Sorry for the drift. . .

Yes it was Jeff, was the only one I could find that would let me copy for trying to explain what I wanted to say. Took me a few minutes but read the article as I went.

Not much tower crane use here in Maine other than Portland, Maine now and then.

Good pick-up Jeff.

Marcel

[Jeffrey R. Pope]

I've raised a tower or two in my time. . .

[Marcel R. Cyr]

Originally Posted by jpope

I've raised a tower or two in my time. . .

I figured that much Jeff with the previous response.

Was a crane operator myself for awhile when younger and gave it up about 16 years ago, nerves cannot handle it and keep telling everyone that you can't run a crane and run a job at the same time.

Was driving me nuts due to the vantage point.

60 ton hydraulic.

Marcel

[rbrady]

Here is a picture of the joist hangers and ledger. If my basic physics are correct the uplift would be about 2 to 1 based on the location of the beam, so if you had 700 pounds at the edge, you would have 1400 pounds of uplift.

[jkogel]

Originally Posted by rbrady

If my basic physics are correct.

Agreed. Any kid that's built a tree fort could see that design is way wrong. They could have moved the doorway, probably just a garden storage shed, or constructed an arch over the door to support the beam properly. You are right to call for a repair.

John Kogel
www.allsafehome.ca

[Richard A. Hetzel]

How do you arrive at 700 pounds at the edge? Take one joist, assuming the joists are 16 inches on centers. Assume two people are standing back to front at the rail, at say 175 pounds per person. That's 350 pounds on one joist, over an area of 2.67 square feet, incidentally a load of about 130 PSF. The load isn't all at the very edge, so let's say its assumed to be at 12 inches from the beam. If the "main span" is 16 inches, then the uplift at the inside end of the joist is 350 x 16 / 24 = 233 pounds.

All of Simpson's face-mount joist hangers are capable of resisting at least that much uplift, and most will resist many times more, as can be seen here: http://www.strongtie.com/ftp/catalog...-2008-p082.pdf

There is nothing wrong with the deck pictured, as long as the hangers are fully nailed as specified by the manufacturer.