# RE: FALLING ICE

• To: "'seaint(--nospam--at)seaint.org'" <seaint(--nospam--at)seaint.org>
• Subject: RE: FALLING ICE
• From: Paul Meyer <PMeyer(--nospam--at)HASimons.com>
• Date: Wed, 26 May 1999 15:16:29 -0700
Title: RE: FALLING ICE

Strength of the ice varies with temperature.  When it's very cold, you may as well assume it's steel.
Force isn't dissipated, energy is...either by shattering the ice (which means you need to know the design temperature to estimate work of fracture) or by deforming the thing it lands on.  Either way, you ultimately generate some heat...0.5 mass times velocity squared and all that.

To get a force, recall that force equals mass times acceleration.  If you assume that the mass decelerates from its falling speed to rest in X seconds, you can get the acceleration, and hence the force.  The trick is estimating the time to go from falling to zero, and guessing the mass of the biggest chunk of ice that might fall.

Best bet is to design  the thing with a flat roof and a parapet so ice can't slide off the roof...
-----Original Message-----
From: Michael O'Neil [mailto:moneil(--nospam--at)f-w.com]
Sent: Wednesday, May 26, 1999 12:14
To: SEAINT (E-mail)
Subject: FALLING ICE

I AM LOOKING FOR INFORMATION ON THE IMPACT FORCE FROM ICE FALLING FROM A TOWER OR TALL BUILDING AND HOW THIS FORCE IS DISSIPATED.

T