Vibration mitigation is often a key element of new structure design. Whether they’re building a super-tall structure or a long-span bridge, designers and engineers understand the inherent value of—and need for—motion and vibration reduction, often using damping technology to address these challenges.
While the industry often focuses on ‘new builds’ and incorporates vibration mitigation into the design and construction phases of a project, requests to address vibration challenges in existing structures are becoming increasingly common.
Post-Construction Floor Vibrations
Recent trends, including those linked to business, wellness, and the environment, are increasing the potential for problematic post-construction floor vibrations that property owners today must address.
On elevated floors, human activity is often the most critical source of floor vibration. Human-induced floor vibrations are typically not large enough to be dangerous with respect to the structural integrity of the building. However, the perception of the vibration can be noticeable and potentially distracting or disruptive to users. In research and medical facilities, even small-scale vibrations that are lower than what humans can perceive can disrupt the function of sensitive equipment.
Impact of Growth: Medical Facility Expansion and Redesign
There is a growing demand to expand facilities, particularly medical facilities like hospitals, as a result of population growth of a city or region. These structures often house sensitive pieces of equipment, such as MRIs, that require extremely low floor vibrations in order to function. These vibrations must be well below human perceptibility.
Hospitals are designed with this in mind, but when a medical facility is redesigned due to an expansion or modernization, the area that will house the sensitive equipment may be moved. This is one post-construction trend that results in the need for an analysis and potential mitigation of the new, repurposed space.
An Investment in Health and Wellbeing
Companies are prioritizing employee health and wellbeing at an increasing rate. One of the ways they do this, repurposing existing office space into a gym or other fitness area, can trigger uncomfortable floor vibrations. The original space, such as a conference room or desk area, would not have been designed to accommodate the high vibration-causing forces that occur in a gym. Such forces can be due to an individual running on a treadmill or a group of people moving in unison in a fitness class. The forces produced by these activities can be significantly higher than those generated by walking and are especially problematic because they often excite the resonant response of the floor.
An analysis of the building and how the addition of a gym will affect employees in other areas of the building is also incredibly helpful when it comes to repurposing certain areas in the office. This type of floor vibration doesn’t pose a risk to the integrity of the floor and structure. However, when building owners encounter this situation during office space repurposing, it is difficult to mitigate.
In an office building, there is likely more than one place you can put a gym or other fitness space. We can conduct an analysis of the floors and potential vibrations to learn how the gym will affect employees and other building occupants.
An analysis can reveal where floor vibrations from the gym will disrupt office workers the least. This is often in the furthest location from the main workspace. Planning the spacing in the gym itself can also be helpful to lessen floor vibrations. This strategy is even more significant when dealing with offices that will turn paperless.
The Unforeseen Challenge: The Paperless Office
Many office buildings were designed for a ‘papered’ office with heavy filing cabinets, multiple printers, and reams of new paper. All of these ‘papered’ office elements add mass to the floor, helping mitigate floor vibration as a result. However, in an effort to proactively respond to environmental and climate challenges, many organizations have embraced new technology and moved to reduce paper utilization in their offices.
In most cases, issues with floor vibrations in paperless offices occur in specific locations, such as near a high-traffic corridor. Most offices re-arrange their layout when they turn paperless, as there is additional space made available due to the absence of filing cabinets and printers. Understanding the implications a paperless office will have on floor vibrations is vital for organizations to minimize the effects on workers.
Designing A Solution: Comprehensive Vibration Analysis
Mitigating floor vibrations in existing structures is achievable. The process begins with understanding the potential for vibration in these structures, using detailed modeling and analysis to do so. Addressing the situation early in the redesign process and incorporating analysis results, can help reduce floor vibration issues later.
In paperless offices, for example, we can conduct an analysis that predicts the floor vibrations expected after going paperless at every point in the office and produce a map of potential vibrations on the floor plan. The analysis will provide companies with an opportunity to consider the effects of removing heavy filing cabinets and re-arranging desks and corridors when planning their new office layout.
Where the analysis predicts uncomfortable levels of vibration, several mitigation strategies can be pursued. Desks and corridors can be strategically placed to minimize vibration. Additionally, floor vibrations can be mitigated by strategically placing mass throughout the space, for example, by using heavy planters with indoor trees, flowers, or plants. It may also be possible to engage the mass of the floors above or below the impacted office floor by installing posts at key locations.
Of course, spaces that are built with the intention of holding large groups of people simultaneously or people moving in unison to a beat require floor damping solutions for the vibrations they will cause. Learn about the specific challenges that floor vibrations present on the dancefloor in Bad Vibrations on the Dancefloor.