Elevating a building by placing it on a hydraulic lift system involves moving the structure temporarily, constructing a pit under the building, installing the hydraulic equipment and necessary structural supports, and placing the building back over the pit. During flood events, the building is temporarily elevated via hydraulic lifts and truss supports, which resist lateral forces caused by wind and floodwaters. During normal operations the building is lowered back over the pit, making the flood protection invisible during normal operations.
There are several advantages to elevating a building by hydraulic lift. First, the hydraulic lift system is essentially invisible during normal activities and, therefore, the building’s relationship to the landscape and any significant landscape features remains unchanged. Second, the system can be tested before flood events occur to ensure that it is working properly, and the rate at which the building is raised and lowered can be controlled, which minimizes the amount of warning time needed to mobilize the system. Finally, the hydraulic lift can be mobilized remotely at the push of a button and by a single person, making this an ideal solution for a site that has a very small staff. Hydraulic lifts can work in all weather conditions, including freezing temperatures, and the system works even when submerged under water.
The major disadvantage of elevating a building by hydraulic lift is that it is an expensive solution and creates more building systems to maintain. Additionally, regular maintenance and inspection of the system must be performed to ensure that it is working correctly.
- Smaller, lighter buildings are the best candidates for elevation by a hydraulic lift system.
- Buildings that have a regularly-shaped footprint are much easier to raise and lower by hydraulic lifts. Buildings that have an irregular footprint may require multiple hydraulic lift systems, which increases the cost and complexity of the flood protection system.
- Excavating the pit required to hold the hydraulic lift equipment becomes much more difficult and expensive if there is bedrock near the ground surface.
- To make room for the pit and hydraulic lift equipment, any below-grade spaces (like a crawlspace or basement) may be lost.
- A redundant power source (like a generator at higher ground), as well as regular maintenance and inspection, is essential to make this a fail-safe solution.
- The building’s utilities must be waterproofed and flexible connections must be installed.
- Before construction begins, it is important to determine if the land beneath your building has the potential to yield archaeology that is important to history or prehistory.
- Farnsworth Flood Mitigation Project: farnsworthhouse.org/option-c-hydraulics