Skyscaraper Mass Damper in use during earthquake

A mass damper is a huge weight suspended inside many new buildings to dampen the motion of the building caused when an earthquake strikes. When the building moves, the mass damper moves in the opposite direction to cancel out or "dampen" the motion.

The attached You Tube video shows the worlds largest mass damper in action in a skyscraper during an earthquake in Taiwan

The fabrication of that enormous weight on-site must have been a very tricky undertaking.

Even though the damper was put together in pieces, the parts still had to be lifted to the top of the skyscraper and installed with tight tolerances.

The damper was something that had to right the first time. Can you imagine what would have happened if they had got the calculations wrong.