The trend of death defying walkways started in 2007 with the opening of the Grand Canyon Skywalk and appears to be gaining momentum. Tourists are thrilled with the exciting views and make a point to visit these spectacular walkways. However, there has been growing concern about the safety of the glass panels.
Just a few weeks ago and only two weeks after the opening of Tower Bridge’s glass walkway in London, a glass panel was shattered from a dropped beer bottle and further damaged by a pair of stilettos. Visitors were assured that it was only the top “sacrificial” layer that broke and there was no real safety concern.
Breathtaking Views from New Heights
The Grand Canyon Skywalk hovers 4,000 feet above the floor of the Grand Canyon jutting 70 feet past the rim. The design is a u-shaped, partially-enclosed cantilevered glass walk with a 2.8 inches thick floor, comprised of five layers of glass. The Skywalk was built to sustain an 8.0 earthquake and is strong enough to support about 71 fully-loaded 747 jets.
If 4,000 feet is just a bit too high for you, perhaps the Willis Tower Skydeck in Chicago is more your speed. Opened in 2009, the Skydeck offers visitors a view of the city from 1,353 feet in the air. Comprised of three half-inch thick layers of glass laminated seamlessly into one unit, the four fully enclosed glass boxes can retract into the building for cleaning and maintenance. Halcrow Yolles, experts in international structural glass design, were able to eliminate all of the structural steel along the perimeter and sides to create a near-invisible support system, making visitors feel as though they are truly floating above the city.
Unlike the Grand Canyon Skywalk (which requires visitors to wear shoe covers), visitors are not required to wear any special footwear to stand on the Skydeck. It was instead designed with a one-quarter inch thick “sacrificial” top layer of glass which can be replaced as necessary. Similar to the Tower Bridge incident, it was this top layer that cracked earlier this year under the weight of some very scared tourists. Halcrow Yolles assures however, that the glass boxes can support nearly 10,000 pounds.
One of the more recent structures to undergo the addition of a glass floor is the Eiffel Tower. In an effort to revitalize the city, the first floor of the Eiffel Tower was outfitted with glass, providing dramatic views to the ground 187 feet below. Made by laminating three sheets of glass with two high-strength films, the final product is about 1.25 inches thick.
While each venue takes a slightly different approach to the increasingly popular glass walkway, there is one structural similarity –- laminated glass. Because glass can be damaged and fail instantaneously, each layer of glass is actually designed to support the necessary load. So, while it might not entirely ease your mind to know that glass can fail – and quite often does – take some comfort in knowing that these glass walkways have been over-engineered to account for such shortcomings and keep you safe.
- Learn more about the lamination process of bullet-resistant glass.
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