The mechanics of a seismic portal

This photo shows the seismic portal before any of the architectural finishes have covered up the components that facilitate the portals movement. Taken from the fixed base medical office building, the unistrut grid system in the ceiling of the portal allows for portal movement towards and away from the cameraman. If the rooms in the background were to move left and right during a quake, the portal stays centered in the photograph while sliding along the hospital edge of slab. See the “X-Axis” photo to understand how this connection works.