This page contains answers to Frequently Asked Questions about the Farnsworth House Flood Mitigation Project.
We know that it is feasible to create a hydraulic solution that has a single point failure system or in other words, has redundancies that prevent the lifting system from failing. The hydraulics solution requires more engineering studies to resolve these details, especially at the connection between the lower and upper decks as they will likely be uncoupled. These studies are currently underway.
The current of the Fox River in this location does not move quickly, but moving debris is a significant concern. Debris containment on the outside of the pit walls is being studied. Additionally, the trusses will have to be braced in the other direction.
Hydraulic systems work in the cold without negative consequences. If we were to consider a water hydraulics system, it would require antifreeze.
Many different systems were evaluated. A barrier dam solution needs vertical elements (visual disturbance) or they could be hydraulically lifted, but it is difficult to create a water-tight seal. Also, the pressure of holding back water above three feet becomes difficult. Even if barriers are erected around the house, once the water rises above 4-5 feet, the pressure would push the water below the barrier system and the water would rise on inside the barrier. Cofferdam systems would work below grade but would need a an above grade curb along with a very complex system of hydraulically raised walls tied to the below-grade cofferdam that would rise up to form the above-grade dam that would somehow have to be sealed to the curb and to the adjoining elements. Rubberized plastic barriers that are inflated with water are not designed for these heights of water and they are not anchored. These systems are not designed for quick response. Limited staff capacity dictates that any new system can be activated by one person in less than two hours during poor conditions. The costs of these systems have not been estimated and the site aesthetics would be compromised.
The unified jacking system synchronizes equal pressure across the structure during the extend/retract process to prevent damage to the glass regardless of differential loads. This system would be employed for the house lifting and the hydraulic lift option.
The lift cycle for the hydraulic system is designed to elevate the building less than 1” per minute over a two hour period.