The viaduct had long been viewed as a barrier between downtown and the city's waterfront, with proposals to replace it as early as the 1960s. Questions of the structure's seismic vulnerability were raised after several earthquakes damaged similar freeways in other cities, including some with the same design as the viaduct. During the 2001 Nisqually earthquake, the Alaskan Way Viaduct suffered minor damage but later inspections found it to be vulnerable to total collapse in the event of another major earthquake, necessitating its replacement.