Tom Surtees has been a Graduate Member of the Institution since 1999, and a Chartered Member since 2007, practising as a structural engineer for 14 years. Here he discusses his work on The World Trade Centre Transportation Hub (“The Oculus”) a unique structure which will serve over 200,000 New Yorkers a day as a subway and railway hub in Manhattan. The Oculus has been shortlisted in The Structural Awards 2016 “Infrastructure or Transportation” category.
I have always had an interest in architecture and the built environment, from houses to bridges and everything in between. Structural engineering was the perfect career choice as it’s a great way to be involved in some of the world’s most impressive construction projects. Your role as a structural engineer is to work as part of a team, applying science to the elements that support the built environment, in order to ensure the safety, health and welfare of the public. Engineering has allowed me to gain a wealth of experience, expanding my knowledge and skills across the world. I trained to be a structural engineer in Britain and had my first job there, working on historical buildings, before moving to Switzerland, then Canada, focusing on bridge design.
The Oculus was a fascinating challenge as it required me to apply my bridge building expertise to an entirely different kind of structure – a railway station. I admire a number of stations, from the classic British, Victorian era, glazed roofs of St Pancras and Paddington, to modern stations that use curved timber in their design, like Bern Station in Switzerland. The Oculus, however, was a very different kind of challenge, as you can see from the design. The inspiration and architectural design is by Santiago Calatrava, an architect with significant engineering ability and training.
COWI applied bridge building methods through the use of “segmental construction”, that is: assembling the structure piece-by-piece in a predefined sequence. The reason this worked so well for the Oculus was that we were able to calculate the necessary construction forces and the deformations at every stage, meaning that not only would the structure remain safe but also construction would progress in the correct direction with minimal need for geometrical correction. It was hugely satisfying to see the final arch piece lowered into place with fractions of an inch to spare either side, achieving our ultimate aim of building the structure through bridge engineering concepts.
Our biggest challenge was the limited site access in downtown Manhattan, which required the steel to be delivered to site through full road closures and police escorts. Public perception was also a factor and it was important to maintain progress from a political perspective, as the World Trade Centre site is a place of emotional resonance for every New Yorker.
The completion of the Oculus has been a step towards finishing the wider re-development of the site, and returning the area to the city that suffered so much from the events of 9/11. A building like this and on this scale has never really been contemplated before and it is testament to all those involved that it was seen through to its ultimate conclusion.
Learn more about The Structural Awards.