The Kent TensegriTree project : collaboration and experimentation in action

By definition, an experimental project involves tackling new, untested ideas, which can bring uncertainty and risk but potential extra value; economic, aesthetic, functionality, etc. Effectively managing that uncertainty, whilst also enabling creative experimentation, is essential. A successful experimental project starts with assembling the right team.

When we talk about experimentation and new ideas in the structural engineering design context how untested is untested? Does it mean untested on that particular site? Or untested anywhere worldwide in the last 30 years? Have key elements of the design idea already been tested in a different setting, such as a laboratory or workshop?  Perhaps the fundamental idea is already well tested and ‘just’ needs to be applied to a new situation?  Of course it is all a question of one’s cultural frame of reference and horizon of expertise and knowledge. Clearly if a design problem can be solved by a brief discussion with colleagues then it’s not really an experimental project, nor is it likely to need noteworthy research and development. But does this mean experimental projects require days of head scratching, and going well outside your comfort zone? Perhaps… but not if the team has the right mix of skills and expertise.

Expedition’s approach to tackling experimental projects, which continues to evolve and develop, begins with an R&D network of experts and technical specialists across industry and academe. This is not about LinkedIn, or a large collection of business cards, or social networking (although all these things might be useful at times). It is about people with trusted opinions and insights, and expertise across a broad range of fundamental areas, with whom we engage in a timely and considered manner. We think that TensegriTree, a new 12m x 12m tensegrity sculpture at the University of Kent, is a great recent example of this approach.

In 2014 we were approached by Don Gray, head of the Kent School of Architecture, with a request to help create a placemaking sculpture to commemorate the 10th anniversary of the department and the 50th anniversary of the University of Kent in the summer of 2015. The brief was for a sculpture based on tensegrity principles which would create intrigue through the relationship between form and force, architecture and engineering. It was quickly apparent that without an unrealistically large budget this sculpture structure could never be the tallest/biggest/longest ever tensegrity. Rather the project was about creating something unique, a talking point at the entrance to the architecture faculty within a limited budget (as appropriate for a public body): a new tensegrity form.

Tensegrity structures, comprising a network of stressed cables and seemingly ‘floating’ compression members, are by their very nature difficult to build. They are amongst the least intuitive of structural engineering typologies to design and analyse, due to complex interdependent technical issues (effects of prestress, non-linearities, very low stiffness , form-finding, etc.). The fundamental mechanical behaviour is more complex than, say, concrete-framed buildings, lightweight footbridges, long span timber roofs, cable nets… Technical complexity also comes with the risk that key stakeholders, such as clients and building users, see it as a black-box design solution which they are not able to ‘own’ and do not feel a part of.

With the above challenges we could see from the outset that we needed to assemble the right experts to collaborate on the project, who we knew from previous projects, research collaborations, PhD vivas and a dinner party! The great thing about experimental projects is that although comfort zones may be stretched, in trying to do something new and exciting there is a great sense of ownership from everyone:

  • Prof Andrea Michaletti, University of Rome, with his expertise in physical modelling and form development of tensegrities, enabled us to run tensegrity model making workshops with the Kent architecture students; thereby having real engagement with the project and a sense of ownership, developing their ideas into the final sculpture form.
  • Howard Woodliffe and Olly Watts, ESGlobal. As contractors with a track record of delivering unusual lightweight structures, it meant that all the way through the design process the team was developing proposals which were economic and practical.
  • Dr Simon Guest, University of Cambridge, an academic specialist in mathematical stability modelling and mechanics. Simon provided validation of the Expedition design and insights to help resolve key technical challenges in a timely manner.
  • Brian Wood, Kent School of Architecture technician and model making specialist, through whom prototyping enabled the students and client body to see the evolving sculpture and also the design team to test and refine key details.
  • Don Gray, head of Kent School of Architecture, a well-informed client who engaged throughout the design and construction process; decisions were made based on a good understanding of the potential benefits and uncertainties of experimentation.
  • …but who/what didn’t the team include? Targeting experimentation, and deciding what not to do is just as important as what does get done. For example, at the conceptual stage we did, amongst other things, consider using some rather unusual materials… but using bamboo had to wait for a different project at Anglesey Abbey….

The expert team complemented Expedition’s experience in creativity, design innovation and lead design coordination.  Without all parts of this assembled team, the work would have taken longer, with much greater uncertainty and risk, and there would not have been so many successful facets to the project:

  • Novel sculptural form which adds to the unique place making of this project: The TensegriTree is, as it stands, a completely new form and geometry in the taxonomy of tensegrities, when almost all other tensegrities physically constructed use pre-established shapes.
  • Budget: all parties covered the costs of their input in terms of time and materials. By contrast, many other tensegrity projects are either loss leaders or use volunteer labour (students and enthusiasts!)
  • Time: the TensegriTree from scheme design to completion on site took just 3 months.
  • Design Life: the sculpture was designed to be a permanent installation, in contrast to almost all other tensegrity structures.

We have been involved with the International Association of Shell and Spatial Structures for a number of years, and the TensegriTree was presented and well received at the 2015 annual conference [download the paper here (678KB PDF)]. The anecdotes from talking to numerous members of the Association’s tensegrity group (the world’s foremost experts) were rather enlightening. Such is the complexity of realising tensegrity structures at-scale that one university research group planned to build one in a week, and ended up taking all summer. Another tensegrity sculpture had been immaculately designed by practicing engineers, but no contractors would tender for the job so it never got built!

So what did we learn from this experience? Perhaps that creative technical experimentation, and turning untested ideas into successful design innovation, doesn’t need to be that far outside one’s comfort zone. Nor does it need to involve compromising on time/cost/quality, with the right team and drawing appropriately on trusted expert research networks. Drop us a line at and let me know what you think.