Vibration control: the vital factor: part 1.


Fatima Taha, Principal Vibro-Acoustic Engineer

An important part of building design.

Vibration may not be the most apparent consideration when it comes to building design, but for some developments, it is a vital factor in delivering the right environment for people and sensitive equipment.

A good example is that of residential developments close to railway lines or in proximity to underground rail tunnels. If vibration is not considered in the design, this can lead to occupants hearing the noisy rumble of trains or experiencing tangible effects via physical perception. Both effects are not congenial with rest and sleep. The possibility of adverse impact (and not just from rail) extends beyond residential markets, and it is not unusual to find issues in theatres, cinemas, studios, hospitals, schools and modern offices when a strong source of vibration is located nearby.

In addition to the above use classes, the Scientific Research and Development (R&D) sector stands out as a building typology with a particular sensitivity to vibration. This category encompasses diverse facilities, equipment, operations, and end-user needs, making it crucial to address vibration requirements on a case-by-case basis.

In these spaces, it is not just the effect of vibration upon occupants that are of concern, but more critically the instrumentation and processes used during experiments, measurements, and observations.

The growing prevalence of vibration-sensitive facilities in urban areas further underscores the importance of vibration design in developments of this type, both new builds and those which are existing and proposed for conversion.

This article specifically delves into elements of vibration control for R&D facilities and how they influence the overall success of these developments in daily use.

What is vibration?

Vibration is the motion of an object or particle about a point of equilibrium and classic examples such as pendulum motion or plucked guitar strings immediately spring to mind when trying to visualise simple systems in action.

We may also imagine how this action may produce a wave-like nature of vibration propagation.

In picturing the tossing of a pebble into a tranquil pond, the disturbance provided by the source (pebble) induces ripples in the water. The energy dissipates as the waves move outward from the point of disturbance.

In the real world of the built environment, sources of vibration produce similar effects in the surrounding soil – though instead of pebbles, they typically comprise road, rail, construction, and industrial operations.

The type of excitation associated with vibration sources can differ too. Some are transient which die away quickly. Others are more continuous in nature. When undertaking measurements of vibration for sensitive developments, it is usually the spectrum of vibration frequencies that is of interest more so than just the overall level. Just as a prism disperses white light into a spectrum of colours, different frequencies of vibration can be measured as contributions distinct in their wavelengths. Understanding vibration frequencies is essential in vibration engineering, as it helps determine the correct course of action in predicting response and setting schemes of mitigation and control.

In part two, we will look at how vibration can affect R&D facilities.