I-Fly was the first indoor skydiving center to be constructed in the Pacific Northwest. This building contains an 80 foot tall vertical wind tunnel in which air moves at a very high velocity up through the center of the structure. This creates the “flight chamber” where customers enjoy the thrill of simulated skydiving. The high seismic risk of the Seattle area presented a new challenge to the standard vertical wind tunnel framing system used in other locations around the world. The tunnel layout leaves little room for standard lateral bracing, and a creative approach was required to fit within the space allowed while conforming to building codes. A combination of concentrically braced frames, steel plate shear walls, and moment frames was selected and designed to work together to form the lateral force resisting system.