#HTE

This Bridge is Cleverly Designed to Slice Ice Into 250-Meter-Wide Strips

Flight instructor Paul Tymstra was flying 7,500 feet over Canada’s Confederation Bridge when he spotted this unusual site. Tymstra snapped a pic and Tweeted it:

Here’s a closer look:

So what’s going on here? The Confederation Bridge, which connects Prince Edward Island with the mainland, has been designed to mitigate the considerable lateral force presented by enormous floating sheets of ice. Rather than beef the piers up to withstand the force, which could require enough material to make the bridge unaffordable, the bridge’s designers introduced a very clever bit of engineering. Look at this elevation view of one of the piers:

From “Confederation Bridge – An innovative approach to ice forces” by T.G. Brown, University of Calgary

The waterline is above the pressure panels, level with the beginning of that 52-degree-angle cone. When a moving sheet of ice contacts the cone, it has nowhere to go but up. This generates a bit of “ice rubble,” and then a crack is induced in the ice, as the sheet simply breaks at that point under its own weight. 

From “Confederation Bridge – An innovative approach to ice forces” by T.G. Brown, University of Calgary From “Confederation Bridge – An innovative approach to ice forces” by T.G. Brown, University of Calgary

The ice can then flow beneath the bridge in neat, rectangular sheets.

Also, to give you an idea of scale, those piers are 250 meters apart. So those ice floes are massive: You could lay the length of nearly two and a half football fields across their width.

Via Kottke

http://www.core77.com/posts/73661/This-Bridge-is-Cleverly-Designed-to-Slice-Ice-Into-250-Meter-Wide-Strips