A photo only an engineer could appreciate. I had hours to kill waiting for my plane, and my attention was quickly grabbed by the unusual construction of the airport. Note first the curved inner beams. As I thought about it, I realized that they probably serve a purpose other than merely aesthetic. Hong Kong can get hit by typhoons (huricanes). Fast moving wind will create very low pressure outside the windows, causing them to want to bulge outwards. This design of the steel structure is a very efficient way of strengthening the walls against this type of force (more so than a simple vertical beam). Now, look at the top of those beams, at the joint. See the next picture for details.