Located in Pennsylvania hill country, about 72 miles southeast from Pittsburgh, is one of the
world's most famous houses. Fallingwater, the stunning creation of architect Frank Lloyd Wright
(1867-1959), has been an American phenomenon since its construction in 1937. Millions of visitors
have made the pilgrimage to the site and stared in awed at the building's concrete terraces hanging
over a clear, swift-running stream. In 1991, the American Institute of Architects voted it the best
work ever produced by an American architect.
Fallingwater is the embodiment of his concept for organic architecture,
which sprang from his love for the land, his desire to create an American art form, and his faith in new
technology. Wright embraced new technology as a way to design buildings which re-connected mankind to the
natural world, and adopted the cantilever as the ideal structural means to express the freedom and repose
he thought was so vital to American life. His buildings engage their landscapes, drawing inspiration from
natural forms to harmonize with them. They provide shelter without confinement; their horizontal nature
secures them to the earth.
Fallingwater has many memorable features: the rough stone walls, the cantilevered
balconies, the bold use of glass, and the remarkable asymmetrical fireplaces. But the way the home is sited
is truly Wright's most stunning accomplishment. Walking over the ground for Fallingwater
with his client, Edgar Kaufmann, Wright noted: "You love this waterfall, don't you? Then why build your house
miles away, so you will have to walk to it? Why not live intimately with it, where you can see and hear it
and feel it with you all the time?"
Despite Wright's brilliance, Fallingwater had a critical flaw. The design did not
provide enough support for the cantilevered section of the house that hangs over the stream. As a result, the
house's famed terraces began to droop as soon as they were constructed, causing large cracks to appear in the
concrete. What is more, the sagging continued over the next six decades. In 1995, the Western Pennsylvania
Conservancy, which now owns Fallingwater, was concerned enough to hire the engineering
firm Robert Silman Associates to examine the house's structural problems. The results of this investigation
indicated that the beams supporting the house were continuing to bend and that the building would eventually
collapse into the stream below if nothing was done.
Repairs to the major cantilever beams were completed in March 2002. The severe over-stresses were
relieved through the creative use of post-tensioning. High strength steel cables were rigged on both sides
of each beam, anchored in concrete blocks, and attached to the beam's end (see
illustration below). The cables or strands were then tightened from the outside
using a hydraulic jack. The tension in the post-tensioning strands exerts a positive bending moment on the
beam, counteracting the negative moment caused by the cantilever action. The strengthening of
Fallingwater's cantilever beams guarantee the structural stability of the house for
years to come. Moreover, the plan stabilizes the house without the need for permanent props rising from
Bear Run stream.
Fallingwater is located 1.5 hours southeast of Pittsburgh. The house is
located on PA Route 381 between the villages of Mill Run and Ohiopyle. Since it is located in a very rural
area, there is no public transportation to the site. For visitor's information see
Source: Silman, Robert., 2000, "The Plan to Save Fallingwater,"
Scientific American, September, pp. 88-95.