What Is a Grout Filled Flat Jack?
A grout filled flat jack is a low-profile lifting and load-transfer device designed for applications where conventional hydraulic cylinders may not fit within the available installation space.
Flat jacks are installed between structural surfaces and inflated using an appropriate high-pressure injection system. Depending on the application, the flat jack system may use hydraulic oil for temporary lifting, or grout or resin for permanent applications.
Grout filled units are designed for applications where the applied force or load is required to remain in place after the lifting or adjustment operation.
Flat jacks are available in both round and rectangular configurations, allowing the equipment to be selected according to the available space, load requirements, and application.
Permanent, Temporary & Transfusion Flat Jack Applications
Flat jack systems can be configured for different applications depending on the structural requirements of the project.
Temporary Applications
Temporary flat jack applications can use hydraulic oil to generate the required lifting force. Once the lifting or adjustment operation is complete, the temporary flat jack can be removed.
Permanent Applications
For permanent load or force applications, the flat jack is installed in position and filled using a high-pressure injection system. Cementitious grout or other suitable filling materials may be used according to the application. Once installed, the flat jack remains permanently in place.
Transfusion Applications
Transfusion systems provide a method of transferring a temporary hydraulic load into a permanent load. The appropriate configuration depends on the engineering requirements of the project.
Round & Rectangular Flat Jacks
Flat jacks are available in both round and rectangular configurations.
The shape and dimensions of the flat jack can be selected according to the installation area, available clearance, required capacity, and structural application.
Low-profile flat jack designs allow lifting equipment to be installed in areas where access is restricted and conventional hydraulic cylinders may not be suitable.
When requesting a flat jack, provide the available installation dimensions and required lifting capacity so the appropriate configuration can be identified.
Flat Jack Capacities & Installation Heights
Flat jacks are available across a wide range of capacities and physical dimensions for specialized structural lifting and load-transfer applications.
Available configurations can include:
- Capacities from approximately 1 ton to 1,240 tons
- Installation heights as low as 1.2 in
- Round flat jack designs
- Rectangular flat jack designs
- Different dimensions to suit available installation space
- Configurations selected according to the required load and application
The actual capacity, dimensions, and installation height depend on the specific flat jack selected for the project.
How Flat Jack Systems Work
A flat jack is positioned within the required installation location and connected to an appropriate injection system.
The flat jack incorporates fluid connections that allow fluid to be introduced into the unit and displaced fluid to exit through the second connection. The exact filling and operating procedure depends on whether the application is temporary, permanent, or uses a transfusion process.
For permanent grout-filled applications, the appropriate filling material is introduced through the injection system and the flat jack remains installed after the required structural operation has been completed.
Because flat jack applications can involve significant structural loads, the installation procedure should be planned and carried out using the appropriate equipment and engineering controls.