A STATE-OF-THE-ART FACILITY
It is five o’clock on a September afternoon, and the streets of Fitzrovia are bustling. School children in uniforms, blue-col- lar and white-collar workers,and stunningly dressed young women pass one another on the pavements of this central London neighbourhood. Behind a small red brick building housing a pub, the first floors of the future proton therapy centre of University College London Hospitals (UCLH) are under construction. The centre is scheduled to open in July 2020, and when it does, it will be one of only two such facilities in the UK offering this advanced technology for the treatment of cancer (see inter- view, page 79). A few streets from the present UCLH complex, Bouygues UK and Bouygues Travaux Publics, working together in an integrated consortium, are constructing a new building. It will have 107 hospital beds on its upper floors, eight operat- ing theatres, and a centre for proton therapy treatment on the basement levels. The demolition, excavation, and construction of the foundations began in 2015 and lasted 18 months. During the project as a whole, almost 400 workers were on the job at the busiest periods.
Last June and July, the cyclotron (the particle accelerator that produces the proton beam) along with the equipment for one of the four treatment rooms was delivered to the worksite. The cyclotron arrived at the end of a 640-kilometre journey from Germany, where it was manufactured. Amazing from the standpoint of its weight (70 tonnes) in relation to its size (that of an automobile), it was lowered into its concrete enclosure by a 750-tonne mobile crane. Owing to the building’s location in the city centre, the related space constraints, and characteristics of the proton therapy technology, the treatment centre has been placed in the basement1. This is the deepest excavation ever done in London”, says project director Charles Pérès.
Almost 80,000 cu. metres of materials have been extracted in digging a huge hole the size of 650 London buses!
1. The expertise of Bouygues Travaux Publics in civil engineering was crucial to the very deep excavation work for the underground portion of the project.
The dense urban environment and the close proximity of the surrounding buildings have not made the task any easier for the workers from Bouygues Travaux Publics. “We have dug the foundation down to a depth of 28 metres, through the water table, and within just 10 metres of a London tube line. To get to that depth, we had to construct a diaphragm wall shored up by four levels of struts2”, adds Steve Meecham, civil engineering works manager. As a consequence, and to meet requirements related to radiation absorption, walls and slabs up to 2.50 metres thick were built around the cyclotron. “The quantity of concrete per surface area is huge, with 80% of the volume located in the lower levels of the building. It’s as though we were constructing a mini nuclear power plant.”
2. Wooden or metal elements used in the shoring of excavation pits and as temporary supports.
at Bouygues UK
Complete lines of piping awaiting installation lie along the corridors on the lower floors. Altogether, more than 8 kilometres of pipes and a large number of electrical conduits will be incorporated in the concrete structure to meet multiple needs, including the colossal cooling capacity required for the operation of the cyclotron and the treatment rooms. The delivery and installation of the last pieces of proton therapy equipment had to be organised so as to disrupt the other activities on the site as little as possible. Because of the number of operations going on simultaneously and the diversity of the work, a digital mock-up is being used to facilitate coordination among all the people involved. “We took an innovative approach from the start of the work by using a very advanced version of a digital mock-up, with 3D up to 6D modelling. The last will be for the maintenance of the structure”, explains Gérald Farque, operations director at Bouygues UK. “It’s going to be widely used in the industry in future years.” In this complex proj- ect, the Bouygues Construction teams’ commitment is total. Charles Pérès sums it up this way: “Working on a project whose purpose is to improve the chances of recovery of young patients is a privilege at the same time as a source of motivation shared by everyone.”