Achieving vibration serviceability in slender floors for the 21st century

Overview

The UN states that the world needs to construct an additional 230 billion m² of building floors between 2020 and 2060. This represents a doubling of the current stock of building floors, equivalent to adding one city the size of Paris to the planet every week.

The vibration serviceability of building floors is critically important, as it has become the governing design criterion influencing their shape, size, and embodied carbon. Every vibration serviceability problem can be broken down into three components: vibration source, path, and receiver. There is considerable uncertainty associated with each of these sub-problems, with the vibration receiver being by far the least understood.

Historically, structural engineers designing buildings have addressed structural design uncertainties through the generous use of inexpensive construction materials, as no better approach existed.

However, in the context of the climate emergency and the need to eliminate material waste there is a need for radical re-thinking of the design process for vibration serviceability. This is particularly so considering the uncertainties that can render floor vibration design predictions unreliable or longer term even useless.

The following questions are therefore emerging:

•  Are the current processes established in recognised floor vibration serviceability design guidelines for dealing with the vibration source, path and receiver fit for purpose?
• Can vibration control move away from adding normally disproportionally large amounts of structural mass and stiffness to reduce really tiny (a few microns) but still problematic vibrations?

To answer these questions, the talk will present an idea for a new framework for dealing with floor vibration serviceability that does not use mass and stiffness to control floor vibrations. 

The framework is based on:

• More detailed consideration of realistic vibration serviceability design scenarios that make use of the latest developments pertinent to the vibration source, path and receiver. As to the least understood receiver: the early findings from and the need for and future application of the new VSimulator research facility in the UK to establish a new generation of vibration serviceability criteria for buildings. This is particularly crucial for understanding human perception of vertical vibration in building floors, which should be based on objectively measured cognitive performance rather than the currently dominant subjective assessment.
• Stopping structural modifications and replacing completely structural mass- and stiffness- with damping-based floor vibration control. Commercially available and usable in practice both passive and active vibration control products will be reviewed. In particular, CALMFLOOR® the new active mass damping technology - commercially launched in the UK and worldwide in 2022 - has the potential to be a game-changer. The mass-produced CALMFLOOR® mechatronics product allows designers to avoid both the excessive use of materials and significant structural modifications.