Thursday, August 21, 2008

Rock paper scissors

Or should I say braced scaffolding, independent scaffolding and scissor lifts. Turns out the scissor lift is pretty heavy. About 2,700 pounds. And with a small footprint, that makes about 300 pounds per square foot. Even though the suspended floors are concrete with reinforced rebar ibeams, the rating is merely 40 pounds per square foot. Oops.

So we quickly removed the scissor lifts from the floor they should have fallen through and just as quickly started cobbling together scaffolding to preserve the appointment with the concrete guys.

But wait (should I say weight). I weigh 200 pounds. My feet are about 12” long and less then 6” wide. Doesn’t that mean I am applying 200 pounds per square foot? Am I too fat for my own house?

Of course, nothing is easy. And point loads, live loads and dead loads are confusing enough before factoring in wheel loads, bending moments, mid spans, allowable spans, and so on.

On further review, the scissor lift can probably be safely used along the edges of the walls.

With walls growing to 17’, the great advantage of the scissor lift is combining the up/down with the forward/backward. Turns out, the up disables the horizontal movement. Thankfully the limit switches, safety locks and interlocks are clearly marked and easy to, ahem, adjust.

So the pour is still scheduled for the 22nd. Our first wall pour since LAST November!

Steve

2 comments:

  1. Self-propelled scissor Lifts are the most commonly used today by businesses, commercial establishments, hotels and warehouses. These are the basic types of lifts that you would usually see in big lobbies of commercial buildings.

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  2. attachments make the scissor Lifts more versatile, and save considerable costs for a company or warehouse that uses it. Safety attachments like fork fenders can be used to warn people of moving scissor lift.

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