Foundation vibration and the added-building effect: Experimental evidence from a ground-borne vibration measurement campaign

Abstract

As new buildings are constructed to accommodate the growing urban population, there is increasing use of sites close to both surface and underground railways. An important design consideration concerns the internal levels of perceptible vibration and re-radiated noise, which may have a negative impact on both the quality of life of occupants and the functioning of sensitive equipment. When considering this vibration serviceability, noise and vibration predictions are often made based on initial measurements of the free-field ground vibration, and by applying empirical relations available in the literature. Coupling loss, floor-to-floor and column-to-floor factors are all defined on the basis of data collected from a limited range of pre-existing buildings, and yet they are applied in practice on a wide range of soil–foundation–building systems. This paper presents the findings of a ground-borne vibration measurement campaign conducted during the construction of a 17-storey building above the Bakerloo line of the London Underground. Vibration levels are compared as the construction progresses over a two-year period, from the original brown-field site to the completion of the building, with the aim of identifying the so-called added-foundation and added-building effects. These effects, which refer to the attenuation or amplification of ground vibration levels resulting from the construction, are quantified in terms of coupling losses that are conceptually different from those found in vibration assessment procedures. Further results describing the variation in vibration levels within the completed building are compared with guideline values and their significance in a design context is discussed.