Catherine Poirriez has been a practising structural engineer for almost four years, working at Passage Projects for the last three. Here she discusses her work on The Future of Us Gridshell, an eye-catching enclosure consisting of 11,000 perforated aluminium panels, 12,040 Bolts, 11,188 Steel Plates and 4,620 Steel Elements. The Gridshell was erected as part of the Future of Us Exhibition in Singapore and has been shortlisted in The Structural Awards 2016 “Small Practices” Category.
I have always loved building things, so I naturally oriented my studies towards a structural engineering career. My interest for the works of Gaudi and Frei Otto particularly pushed me to work on complex shapes structures.
I have been lucky to work on some great projects during my career, including the design of a 106m span dome in Manila, which I worked on for two years – it’s a really big and impressive structure and seeing it almost finished makes me very proud.
The main difference between the Future of Us Gridshell and the other projects I have worked on was the tight schedule, which demanded very close teamwork. The coordination between all the parties had to be super-efficient to ensure that all the parameters – whether aesthetic, structural, fabrication, transport or installation - were taken into account at the same time.
As the Gridshell geometry is very complex we took care to rationalise and define the lines of the structure from the free-form shape given by the architects, Singapore University of Technology and Design Advanced Architecture Laboratory. Again, this required very close collaboration, enabling us to achieve a final geometry in four weeks, fully coordinated between the structure and the facade. In fact, whenever an issue appeared the whole team of contractor, engineers and architects met to discuss it and propose solutions. The boundaries between parties were very blurred and we can truly say that throughout the project we worked as one.
I am really proud with what we achieved with the structure, and was particularly satisfied with the very simple idea to divide it into vertical arches, to rationalise the geometry. When one sees the shape of the Gridshell, this approach is not the most obvious solution - but it turned out to facilitate everyone’s work throughout the project.
Speed and simplicity of assembly was a crucial factor in the project’s success. One critical aspect was to design a structure that could be simply fabricated and assembled, and this was designed in right from the beginning of the project. This meant that the contractor should be able to fabricate the structure from the easiest material to handle - steel plates - and assemble the structure with the simplest possible tools, which means bolts. This was a major challenge to achieve with a project of such complex geometry as the Gridshell.
When you see the structure's 3D model on the screen of your computer, you never really feel the scale of it - so it is always a pleasure when you see the work completed. When the work was finished we looked around inside and were very impressed by the quality of the space and the shades provided by the aluminium panels.
Clients, architects, engineers or contractors can sometimes be afraid of structures with complex geometries, because it can lead to complicated and costly steel members, connections and facade fixings. I think the main achievement of the Gridshell was the way we redefined the notion of simplicity by expressing a freeform, unusual geometry with basic construction methods - showing that with great design it’s possible to achieve a ‘simple’ complex structure.
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