Last week's answer

Question: Connecting Prince Edward Island to mainland Canada, the 8-mile Confederation Bridge spans the frozen Northumberland Strait. During winter, massive ice floes moving with ocean tides hit the bridge piers. To prevent these crushing ice sheets from destroying the hollow concrete supports, how did civil engineers design the waterline geometry of each pier shaft? 

Answer: They installed 52-degree conical ice shields that force incoming ice sheets to ride upward until the ice's own weight causes it to snap and break downward.

These massive concrete shields break up the sea's ice layer as it flows into them, as they are raised by the structure's inclined surface. The ice then bends and breaks under its own weight. 

Source: The BYU Design Review