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IASS-SLTE Symposium 2014: Shells, Membranes and Spatial Structures: Footprints


IASS Symposium 2014

SESSION: General 9: Computational Tools, Shape Finding and Optimization

Form-finding for ground vibration reduction in an urban scale

< Table of Contents for General 9: Computational Tools, Shape Finding and Optimization
  • Proceedings Name: IASS-SLTE Symposium 2014: Shells, Membranes and Spatial Structures: Footprints
  • ISSN: (Electronic Version) 2518-6582
  • Session: General 9: Computational Tools, Shape Finding and Optimization
  • Title: Form-finding for ground vibration reduction in an urban scale
  • Author(s): Vedad ALIC, Kent H. PERSSON
  • Keywords: Conceptual design, form finding, optimization, urban scale, vibration reduction, surface masses, soil dynamics.
Abstract
Form-finding is traditionally thought of in context of structures whose performance is dependent on their shape, such as grid-shells or cable nets, among others. This paper extends traditional form-finding by investigating the search of forms in an urban scale that are effective in reducing vibration propagation from external sources, such as highways, high-speed railroads and industrial plan. The aim is to lower their negative impact on the built environment. The scale of the urban forms can range from buildings, down to stones or concrete blocks, depending on site conditions (geometry, medium of propagating waves, targeted frequencies). In this paper a state-of-the-art synchrotron facility, that is located both near a high-way and a city will serve as an example. The facility is located on clay which has resonant frequencies within the range that the facility is sensitive to. It is investigated if further urbanization of the area between the facility and the city can contribute in mitigating vibrations from the external sources, in order to ensure operational conditions for the facility. Forms are investigated numerically by placing out blocks of masses on top of the soil surface, in a tool developed for an iterative study. The vibration levels from external sources are evaluated, with the aim of finding optimal solutions in terms of vibration reduction and suitability as an urban plan. Results indicate that masses on the ground can be used as a means to mitigate ground vibration, but in order for them to be effective they need to be very heavy. Locating masses in a careful manner can be effective for vibration mitigation, and by combining masses of different densities reduction in a wider frequency range can be reached. Some conclusions from the research were: Forms where masses are applied continuously over the whole area can lead to amplification due to lensing or acting as wave guides, however, all discrete organizations of masses show reductions in vibrations. Density variation for the different masses has greater effect than their position.

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