Soil-Structure interaction in Building Base (Vibration) Isolation
Buildings near busy roads and railways can be subjected to ground-borne vibration, resulting in unacceptable levels of structure-borne noise and vibration for the building occupants. These vibrations are a significant consideration for the designers of new buildings, and they often limit a building's serviceability unless appropriate mitigation measures are taken.
Building base isolation is one such measure that limits the transmission of vibration into a building by introducing either elastomeric bearings or steel springs between the primary structure and the foundation. Although this has been used for a long time, the available design guidance is limited.
The required performance of the isolation heavily depends on the purpose of the building and, because vibration isolation is an integral part of the building design, it must be considered carefully during design. Each project necessitates a tailored and custom-made solution depending on the load distribution, the type of structural elements, the acoustic requirements and the available supporting surface area.
This course presents some recent findings from a theoretical study into the effectiveness of base-isolation for a typical multistorey building founded on piles adjacent to an underground railway. It establishes which aspects of the soil-structure interaction between a building and its foundation are significant, and considers some of the practical implications for isolation design.
The course begins by identifying the typical sources, understanding the vibration transmission mechanisms and examining the vibration and noise emission at the receiver. It then proceeds by summarising the various components of soil-structure interaction that govern the vibration transmission at the building-foundation interface and discussing some recent modelling work that has sought to understand better this soil-structure interaction and the physics behind this so-called coupling loss between a building and the supporting ground. This course focuses specifically on this interaction because it is essential for predicting the dynamic behaviour of buildings and choosing, subsequently, the vibration isolation solution.
In conclusion, different possible locations for the building isolation are presented, together with guidance on how to select the best location from the three presented: ground floor columns directly on the isolation bearings; a ground floor slab that ties together the feet of these columns, just above the bearings; and a ground slab or pile cap that ties together the pile heads, with the bearings on top of this and the building columns directly on the bearings.
Learning objectives:
Building base isolation is one such measure that limits the transmission of vibration into a building by introducing either elastomeric bearings or steel springs between the primary structure and the foundation. Although this has been used for a long time, the available design guidance is limited.
The required performance of the isolation heavily depends on the purpose of the building and, because vibration isolation is an integral part of the building design, it must be considered carefully during design. Each project necessitates a tailored and custom-made solution depending on the load distribution, the type of structural elements, the acoustic requirements and the available supporting surface area.
This course presents some recent findings from a theoretical study into the effectiveness of base-isolation for a typical multistorey building founded on piles adjacent to an underground railway. It establishes which aspects of the soil-structure interaction between a building and its foundation are significant, and considers some of the practical implications for isolation design.
The course begins by identifying the typical sources, understanding the vibration transmission mechanisms and examining the vibration and noise emission at the receiver. It then proceeds by summarising the various components of soil-structure interaction that govern the vibration transmission at the building-foundation interface and discussing some recent modelling work that has sought to understand better this soil-structure interaction and the physics behind this so-called coupling loss between a building and the supporting ground. This course focuses specifically on this interaction because it is essential for predicting the dynamic behaviour of buildings and choosing, subsequently, the vibration isolation solution.
In conclusion, different possible locations for the building isolation are presented, together with guidance on how to select the best location from the three presented: ground floor columns directly on the isolation bearings; a ground floor slab that ties together the feet of these columns, just above the bearings; and a ground slab or pile cap that ties together the pile heads, with the bearings on top of this and the building columns directly on the bearings.
Learning objectives:
- Recognize the importance of building base vibration isolation solutions.
- Understand the vibration transmission mechanisms, the vibration propagation path and especially the soil-structure interaction.
- Learn about what needs to be considered and what aspects need to be paid attention to during structural design and their impact on vibration propagation.
- Discuss vibration control strategies based on the foundation chosen.
- Discuss the added value of intermediate measurements on foundations.
- Select the best location for the building base vibration isolation solution.
