Advanced medical, research, and manufacturing facilities require the use of high-precision equipment whose performance can be adversely affected by extremely low levels of floor vibration. We measure the floor vibration and assess the vibration performance using equipment manufacturer specifications or the generic criteria for sensitive equipment when no formal specifications are available.
Manufacturers frequently provide specific vibration criteria for vibration-sensitive equipment. There is no one industry standard for the presentation of these criteria, but we have the experience and flexibility to accommodate any form of manufacturer-provided criteria into our floor vibration assessment.
Flexible Floor Vibration Assessment
Floor vibration problems are not limited to high-tech manufacturing or healthcare facilities. The design and layout of modern office spaces are increasingly based on higher staff density and an open floor plan with fewer full-height partitions that visually and functionally break up a space. This is a recipe for increased incidences of floor vibration complaints.
Some floor systems are particularly susceptible to walking-induced vibration. Many offices are based on "open" floor plans with cubicles. This has two effects: (1) it increases the number of people who work in a given area and, therefore, the number of occurrences when someone is walking through the space and (2) reduces the number of floor-to-ceiling non-structural partitions. Even though these partitions are considered to be non-load bearing, they can have a beneficial effect on the vibration characteristics of the floor. They act as stiffeners that raise floor resonance frequencies (making them less susceptible to walking-induced vibration) and increase the damping (vibration energy dissipation) through friction in their connections and construction.
Identifying the Source of Vibration:
Our structural dynamics testing and analysis experience with a wide variety of aerospace, mechanical, and civil engineering industries means we have the ability to take data apart and figure out what makes it tick. Identifying the sources of vibration is the first step in reducing or eliminating their effect. Walking-induced vibration looks very different from vibration caused by rotating machinery, which looks very different from vehicle-induced vibration. Once we understand the source, we can explore vibration control options.
Pre-Construction Site Vibration Assessment
We can also characterize the vibration at a proposed site for a sensitive facility and then perform structural dynamics analyses of the future structural system to determine whether the existing vibration environment will cause problems and, if so, develop recommendations for design modifications to provide an acceptable vibration environment.
Roadways, large mechanical services buildings, and rail transportation systems are common sources for ground-borne vibration that enter buildings through the foundation structure. Column modes of the structure can actually amplify and transmit the ground-borne vibration to the upper levels. We will measure the vibration at the site before construction begins and determine how that vibration propagates through the proposed building.
Optical Tracking System Self-Induced Vibration
Operating mechanical systems often contain gears and motors that are responsible for self-induced vibration that can adversely affect the performance of the mechanical system. An optical tracking system is experiencing degraded performance and a series of operating vibration measurements are acquired to diagnose the underlying cause of the problem. The tracking system can be operated at a variety of speeds: x1, x4, x8, and x64. Vibration data are acquired for all possible speeds. Higher-order spectral analysis methods (the Bispectrum and Trispectrum)
Related Technical Reports
We perform on-site vibration tests and measurements on short notice:
Contact Dr. James Lamb at 214.412.8388 or via email at firstname.lastname@example.org