Answer by Brian Roemmele:
If a rock was thrown at this glass house, little to no damage would occur.
The instantly iconic and artistically beautiful Fifth Avenue Apple store stands like a glass oasis amongst the almost century old granite and cement buildings in this area. This is an architectural marvel.
Stronger Than Your Average Glass
The 32 foot perfect cube is far more sturdy then it would appear to be. Apple uses a patented process that creates some of the strongest Industrial Grade Structural Glass in the world. This is the masterful collaboration of Apple, including Steve Jobs directly working with architect Bohlin Cywinski Jackson working for. Up until just recently, there was only one company in the world that could produce this Glass for Apple: Seele GmbH & Co. in Gerthofen, Germany.
During the design, tests were carried out using “Nastran” and “Lucas” FEA software, designed to calculate stresses and deformations in complex geometrical structures. The results of the FEA is a color-coded diagram that focuses on load limits of the glass. The lamination process is similar to the glass you would find in an Automotive window, but far, far stronger. Not only is the glass supporting the vertical load of the entire structure, it also completely supports the horizontal loads created by the structure itself and external forces such as high winds with the aid of 25 Glass Fins that run the height of the cube.
The Apple Cube Almost Stops A Speeding Bullet
There are no doubts that a thrown rock at most distances would simply bounce off the Glass panels in most cases. At worse case if hit on a support or corner, there would be some small chips expelled. The Glass can take a rather hard hit with a hand hammer and not offer up anything more than a few external chips. A Bullet from a typical hand revolver would cause a small entry hole, but certainly would not shatter the glass. This is not “Bullet Proof” glass, but in some circumstances a bullet will be deflected by the glass. It is the flexibility the Lamination process creates for the glass that really is the secret to it’s strength. A wonderful presentation on the structural efficiencies of Laminated Glass by the Institute Of Structural Engineers, can be found here:
The Cube is Changing
Just when the the world has gotten used to this amazing structure, Apple is changing it for the better. This process will actually make the cube stronger and more amazing to look at. Apple is in the process of replacing the 90 Glass Panels for just 15!
There are a number of reasons for the change. One of them was a few very minor flaws in the original design that was causing a little more horizontal stress then what was projected, although it would not have caused a failure of the structure.
The new design will have far less connectors and about a 20% increase in panel strength in comparison to the older manufacturing process. Apple found that North Glass Safety Glass Co. in China was able to produce better structural support in comparison to Seele GmbH & Co. Apple tested this process with curved glass at the Sanlitun store in Beijing. Thus, Apple’s remodeling will be complete later this fall.
Apple is far from done with its use of Structural Glass in its stores and at the proposed new headquarters. In the end, glass is still glass– but as technology keeps improving, the strength is being pushed to rival other traditional building materials.