The US Bank Tower’s terrifying Skyslide attraction is a glass slide that hangs off the side of the building, connecting the 69th and 70th floors. The building itself is designed to lean up to 30 feet during an earthquake, but what about the slide: How would it stand up to a big shaking? "It would be scary as hell, but the glass wouldn’t break," structural engineer Michael Ludvik of M. Ludvik Engineering, which designed the slide, tells The Architect’s Newspaper.
"We tested the pants off of absolutely everything," says Ludvik. The slide is built out of 1.25-inch thick glass panels, the majority of which are "tempered and laminated" with SentyGlass, a special element that’s used for hurricane glazing in Miami-Dade County.
In parts of the slide where, because of "complex bent geometry," SentryGlass wasn’t an option, Ludvik says, "we chemically strengthened the glass to be as strong as steel."
There are other components that make the slide earthquake-safe, Ludvik says. "This thing is a machine as much as a structure," he told the newspaper.
The design of the slide includes a "complex array" of so-called soft touch connections, which contain ball joints. These joints allow the slide to move separately from the building, so it could sway on its own during a quake. The ball joints are supposed to be incredibly strong: Ludvik says they are capable of carrying a New York City subway car’s worth of pressure on each soft touch connection.
"The wonderful contradiction of the slide is that it only feels unsafe," Ludvik told Slate in March. "It’s built with factors of safety and levels of redundancy which would make the most conservative engineer blush."