Advanced Technologies for Mitigation of Human-Induced Vibration

There is an inexorable trend for civil engineering structures to become more slender and lightweight, as engineers strive to design more efficient structures with reduced economic cost, reduced carbon footprint and increased flexibility of usage. Unfortunately, due to their reduced mass and stiffness these structures are inherently lively and there is a desperate need for advanced technologies that are capable of ensuring satisfactory vibration performance when people walk, run and jump on them. There are two key issues to address:

(1) Technologies are required to deal with existing vibration problems, which are increasingly and widely observed in structures such as floors, footbridges, sports stadia and staircases. Currently available technologies are insufficient to deal with the majority of these problems, which means that extensive and low-tech structural modification schemes have to be employed that are both expensive and highly disruptive.

(2) If the ambitions of structural engineers for ever more slender and efficient structures are to be realised, it will be necessary to 'design in' advanced methods of vibration control when developing new structures. This is because many contemporary structures are already being designed at their limits of vibration acceptability. Unfortunately, the new technologies required for this transformative design approach are not yet available.

In the last five years, the applicant and his team have carried out exciting research into active control of vibration in floor structures, in which large reductions in vibration have been achieved that are not possible using other floor control technologies. They have also demonstrated that significant material savings may be made using this technology, which has the potential to significantly reduce the carbon footprint of new buildings. This is the main vision for this fellowship and the future, where advanced and intelligent vibration control strategies will become commonplace in structures subject to human dynamic loading.

However, a solution that works for floor vibrations from a single person walking is not necessarily going to work for a sports stadium with many thousands of people jumping during a rock concert. Hence, what is required is a required is a complete 'suite' of control technologies, from which the most appropriate solution may be chosen and implemented for any particular vibration problem. In these days of active noise cancelling headphones and semi-active vehicle suspension systems, it is time for these advanced technologies to find their place in civil structural engineering, to solve the unique problems of human-induced vibration.

Hence, in this research a comprehensive framework of technologies will be developed, so that the most appropriate technologies may be selected for a particular application. This will be the first time in the world that such a holistic approach has been taken to mitigation of human-induced vibrations. Fundamental research into a range of these technologies, including active, semi-active and hybrid vibration control techniques will be carried out to prove their viability in the civil engineering sector through analytical modelling, laboratory testing and in-the-field implementation. Finally, extensive industrial liaison and public outreach activities are planned to ensure the take-up of these technologies, which is the key way in which this research will benefit UK plc.

The key beneficiary of the proposed research is the UK civil engineering and construction industry, who at long last will have access to effective vibration control technologies. This will ensure that they can deal with vibration problems encountered with structures in service in a relatively inexpensive manner and with minimal disruption to the occupants. In addition, the vibration control technologies will facilitate the future design of more efficient and slender structures with satisfactory vibration performance, which will use less materials and hence have reduced economic cost and carbon footprint.

The following activities are designed to maximise the industrial impact of the proposed research:

- Individual visits will be made to UK consultants and technical presentations given at the Institution of Structural Engineers, to disseminate research and to seek input into future research directions.

- Steering group meetings will be help biannually, which will include a number of industrial participants.

- Mitigation technologies will be implemented on real civil structures and case studies made available.

- PR will have input into national and international working groups to disseminate the latest research and develop guidance to ensure the take-up of the new vibration control technologies.

- A textbook will be written that will be accessible to practicing engineers.

- The developed technologies will be exploited commercially, to ensure that the technologies are available for use by the industry.

The owners and users of buildings will benefit through the increased slenderness of structures that may be achieved, leading to cheaper and lower carbon structures that have increased flexibility of usage. Users of controlled structures will also benefit from an enhanced vibration environment, leading to increased comfort and, in the case of offices and structures housing vibration sensitive equipment, increased productivity. In many cases, building users are comprised of members of the general public, who will benefit from reduced vibration in structures such as public buildings, footbridges, sports stadia, arenas and theatres.

PR will also dedicate valuable time to development of public outreach activities. Structural dynamics is inherently a very visual subject, whereby scientific principles can easily be illustrated using videos, animations and even physical models. The following public outreach activities are planned:

- Imaginative physical models, posters, presentations and simulation software will be developed to demonstrate the fundamental principles of vibration problems and the mitigation technologies developed.

- Opportunities will be sought to promote civil engineering (and particularly structural dynamics) to the wider community, especially schoolchildren who might be interested in a future career in engineering. In particular, PR will volunteer to give demonstrations to and develop interactive activities for school children attending the University of Sheffield Engineering Summer School and at UCAS open days.

- A web site will be designed specifically for non-experts, to introduce and explain the problems of human-induced vibration and the technologies being developed to deal with these problems. This will make use of some of the virtual simulations mentioned above, and will include collaborative and interactive elements to encourage active exchange of knowledge.

- To maximise the opportunities for public communication of the research, all researchers employed by the LF and associated research projects will attend a Royal Society course on public communication and media.