Floor vibration problems in offices near rail lines can be addressed later in a short period of time!
The office working environment deteriorated due to railroad running vibration caused by the new track construction. By adopting the ultra-thin vibration control device Floormate, it was possible to install it under the OA floor & install it in a short period of time during the holidays, making it possible to take countermeasures afterwards without the need for large-scale construction work.
issue
In buildings located near railroad tracks, vibrations generated by the railroad can be transmitted from the ground to the building's columns and beams, causing floor sway.
Company A's office, located near a railroad track, was a five-story steel-frame building that had never been affected by vibration. However, after the construction of the new track, the floor shaking increased each time the train passed by, and the work environment deteriorated.
Figure 1: Image of the building
Figure 2.
Measurements of floor vibration during the passage of a railroad revealed that the floor resonates and amplifies in the vicinity of 10 Hz.When evaluated using the occupant performance evaluation guidelines of the Architectural Institute of Japan, it was found to be between V-90 (90% perceived probability) and V-70 (70% perceived probability), which is a hailstorm where most people feel the shaking.
In the measures taken,
- ・Existing building does not allow for large-scale construction.
- ・Finish the work in a short period of time so as not to affect the business.
In light of the above, we decided to use the ultra-thin vibration control device Floormate (hereinafter referred to as “FM”), which enables vibration countermeasures to be applied to existing buildings afterwards in a short construction period and in a small space.
Figure 3: Vibration acceleration measurement results when no measures were taken
counter-measure
The floor finish of the room in question was an OA floor with a 50 mm bosom, so FMs with a thickness of 44 mm can be installed under the OA floor.In this case, 10 units, or 4% of the effective mass of the floor in question, were installed.
Figure 4: Floor Mate Installation
Figure 5: Floor mate installation locations
result
After installation of the FM, floor vibration during train passage was measured with the vibration control function OFF for five measurements and ON for six measurements, and evaluated based on the average value of each.
When the vibration control function was turned off, the level exceeded V-70, but when it was turned on, the level was reduced to below V-70.
The series of work, including partial removal of the OA floor, installation and adjustment of FM, effect measurement, and restoration of the OA floor, was completed in one day when the office was closed, and the vibration environment was improved without affecting business operations.
Figure 6: Effects of Floor Mate Floor acceleration when passing a railroad
Related Pages
- added. This report compares AMD (Active Mass Damper) and TMD (Tuned Mass Damper), which are commonly used as vibration countermeasures for building floors, in terms of features, cost, and ease of maintenance. Please use this report when considering vibration countermeasures.
- Product Information Floor Mate