Engineers have often observed that tube bending can change the mechanical properties of a hollow structural section (HSS). Typically the yield and tensile strength increases as a result of tube bending, but there may be a loss of ductility, however minor. And any decrease of ductility is likely to become an issue when curved tubes are to become the frame of a structure in a seismic zone.
Nevertheless, the structural, seismic, and blast engineer for the Mineta San Jose International Airport, Magnusson Klemencic Associates (MKA), solved the issue of using curved tubes in the most highly populated and active earthquake area in the United States.
Among the solutions MKA developed was a “special truss moment frame” which performed well while resisting gravity, earthquake and wind loads all in one system.
Another solution was the use of Teflon-coated elastomeric bearing pads wherever the curved tubes meet the curbside level. These bearing pads allow up to 28in. of horizontal movement.
Once again, ingenious engineers have developed creative solutions resulting in amazing architecture while ensuring safety during seismic events.
Mineta San Jose International Airport