Technical EASTERN CAMPUS LAYOUT – PHASE 1 – NOVEMBER 2013 How to rebuild an operational airport eastern campus layout - phase 1 - november 2013 Height restrictions mean crawler rather than tower cranes must be used on T2A 1 Terminal 2A Phase 1 when complete 2 Car Park East operational 7 Terminal 2B pier Phase 2 open 8 Potential for station box for Track Transit System (TTS) to be built and Lima taxiway TTS tunnels to be safeguarded Baggage basement built and tunnel safeguarded across Lima taxiway 3 Baggage link to Terminal 1 4 Vertical circulation core connection to tunnel when complete 9 5 Passenger tunnel to T2B when complete 10 Cooling station for air 6 Preparation for Europier demolition Rebuilding Heathrow’s Terminal 2 unearthed significant environmental and logistical challenges that demanded a great deal of creative thinking conditioning 6 3 9 4 project report Damon SchÜnmann 2 Project Phase 1 of Heathrow Terminal 2 Start date October 2010 1 10 Diagram for illustrative purposes only Completion date 2013, opens 2014 Big projects will never fail to present challenges, and the redevelopment and consequent expansion of Heathrow’s Terminal 2 demonstrates a pretty good range of what can be thrown at contractors. The scheme involves the demolition and replacement of the passenger terminal (T2A), 10 new aircraft piers (T2B) and a possible future passenger terminal and car park expansion (T2C). BAA Eastern Campus programme director Joanne White says: “It’s very challenging because the T2B [aircraft piers and stands] work is all airside. “This means vehicle deliveries must all be security screened, with the workforce vetted before arriving on site. “T2A alone is one of the biggest construction projects in the UK. But the total current £2.2 billion project is one of the biggest in Europe, with only the likes of Crossrail exceeding it. And the proposed T2C expansion will also be in the same ball park.” Passenger capacity T2C would increase passenger numbers from 20 to 30 million by expanding the car park and terminal capacity. The overall purpose of the project, says BAA, is to develop Terminal 2 for the Star Alliance airline consortium to ensure it is a convenient hub for onward flight connections. The old T2 demolition was 18 | 28 July 2011 Client BAA The T2B pier and basement T2A passenger terminal design and build main contractor HETCo (Laing O’Rourke and Ferrovial Agroman jv) T2B (aircraft piers and stands) main contractor Balfour Beatty Design Ferrovial Agroman M&E Hoare Lea Aircraft stands, cooling station, service diversion Scott Wilson London Underground structural remodelling Arup T2A architect Foster + Partners, Vidal + Asociados T2A electrical infrastructure UK Power Networks Services Car park Laing O’Rourke completed last year, and BAA says this included the recycling of 95 per cent of the material, adding that the new building will produce 40 per cent less carbon than the old one. An excavation that is currently under way will safeguard space for an underground baggage handling system as well as a light rail line connecting the main T2A transit building with the T2B aircraft pier (and later, the proposed T2C passenger expansion). This excavation requires 600 vehicles a day at the peak of the works, with soil either becoming backfill or being used to cap a nearby tip – as a result, 90 per cent of it is reused. Ms White says: “The new north-facing T2A passenger terminal will afford excellent solar gain protection and a canopy roof extension will provide more shade to prevent excessive summer heat, as well 8 7 5 £2.2bn Value of T2A and T2B as weather protection for passengers arriving from the car park.” New aircraft The building Total number of has been stands at T2B site workers designed with several key things in mind that include biomass unit for supplying hot environmental considerations, water as well as heating the whole site constraints and speed of eastern campus. construction. Mr Pickard explains that being T2A programme leader Duncan an operating airport, the site Pickard says the north-facing has a variety of site constraints. windows within the roof still For example, work must not allow sunlight without the solar interfere with the line of sight gain. “So you reduce your carbon from the control tower to the footprint by turning off the ends of the runway and lights,” he says. “The brise-soleil means you have sufficient canopy construction equipment must not block the overhead horizontal shading without preventing radar pulse. natural light.” Other sustainability features include borehole water that feeds Heavy influence the cooling station – negating the Although the busy airport need for potable water – while environment necessitates a quick the energy centre incorporates a build, the site constraints have 10 4,500 www.cnplus.co.uk heavily influenced the construction sequence and methodology. “We are aiming to build T2 in 40 months, that is from spring 2010 to autumn 2013,” says Mr Pickard. “But while T5 had 30-odd tower cranes, we can’t use any because of the impact on the sight lines from the control tower. “The inner horizontal surface is 45 m above the runway threshold, which provided another construction constraint. “While T5 had 30-odd tower cranes, we can’t use any because of the impact on the sight lines from the control tower” duncan pickard – T2a programme leader www.cnplus.co.uk “This is an area that would be needed should a plane get into difficulty,” he says. “So we had to have a design that allowed crawler cranes to construct from T2A’s leading edge, which means a weight limit of 20 tonnes for any one element.” Building cores The passenger terminal building is based on 12 vertical cores measuring 9 m x 18 m x 24 m high. To maximise speed and quality, the project team opted for offsite manufacture for the M&E, using designed-for-manufactureand-assembly (DfMA) products, while the 27,000-tonne steel frame is being fabricated and erected. “There is a an ethos on the project that if it’s simple do it onsite, and if it’s complex do it offsite,” says Mr Pickard. The four-floor building has a composite metal deck while the roof is a traditional Kalzip aluminium standing seam design. BAA T2B programme leader Richard Walker explains the process. “The basement for a baggage and light rail transit system in the next phase of T2C is under the main aircraft pier here at T2B. It’s 360 m long, 60 m wide and 15 m deep, and with the other subsurface connectivity structures will entail 2 km of diaphragm walling. “The designers opted for diaphragm walling over a more traditional open cut and reinforced concrete wall system due to the reduced footprint of the construction works, an easing of impacts on logistics, and to create a more flexible construction sequence. “The north and south sections of the pier will be delivered using top-down construction, enabling the early commencement of the superstructure. However, the centre section will be built from the bottom up, providing for the earliest completion of the critical path subsurface plant rooms and communications rooms. “At the same time as the diaphragm walling, about 700 large-diameter bored piles and plunge columns are being installed from ground level to take advantage of the predominantly existing concrete stand and taxiway pavement. “The main excavation is about 750,000 cu m, with sands and gravels overlying London clay. All excavated material is being recycled for use in the works or for environmental capping off site. This includes the existing pavement quality concrete, which is being crushed on site for piling mats or stored for the future stand and taxiway works.” The structure is glazed on the east, south and west faces, while the north face is temporary to allow the structure to be extended further to the north. Mr Pickard says the passenger experience is intended to give them the impression of following a wave as they walk beneath the undulating ceiling. Work has included excavation for a basement for the phase 2 baggage system installation – a function that is currently being handled by Terminal 1 for outbound flights. The basement has a raft foundation to minimise movement and spread the load. Mr Pickard says: “Traditionally you might have designed a building and then worked out how to build it. “What we have done is have a concept of what we wanted, and then taken into consideration all the constraints before deciding how to build it first. The design informs the method of construction. “For example, the modular M&E and the steel roof sections and frame need to be assembled with crawler cranes. The steel sections must be able to be 28 July 2011 | 19 Technical “We only have about 400 people on site, which is perhaps half the amount needed for a traditional job of this kind” duncan pickard – T2a programme leader delivered by trucks without escort. It’s all about minimising logistics as there is one main road tunnel entrance to the central terminal area. An escort would impact on Heathrow operations, as it takes out both of the three lanes coming in. “It’s all about being the invisible silent builder that does not impact on Heathrow’s daily operation.” 20 | 28 July 2011 fitting material deliveries to the airport’s schedule “We have to protect the airport from disruption and, at the same time, ensure the logistics plan is capable of supporting the construction programme – and that’s a constant balancing act,” says BAA Eastern Campus logistics leader Tim Brent. The two key themes are movement of materials and people, back and forth. “With materials, it’s a large site – over 1 km long – and the perimeter is 3 km,” he says. “Over the whole project we have 400,000 vehicle deliveries. And we have about 4,500 people across T2A, B, the car park and the baggage handling element of the scheme. “However, material deliveries don’t begin until after 9am to keep them outside of peak passenger times. “The Icelandic ash cloud last year actually had a positive effect on work at Heathrow: it accelerated the programme, since the airport was not operating for a limited period. But we had to be ready to decelerate at short notice.” And other weather conditions affected the contractors’ role beyond the ordinary. “During the adverse winter weather, site workers helped clear ice and snow from the airport,” he says. Project director of the HetCo JV between Laing O’Rourke and Ferrovial Agroman Pablo Riesco says: “In a project like this, in the middle of the airport, the most important thing is getting the logistics right from the very beginning. We have 25-30 lorries delivering steel every day. On T2A we have delivered 95 per cent of the materials to the landside. But to the aircraft stands on T2B, they have to go airside. “The project reached a milestone before the beginning of June by completing the entire basement and substructure, and we are talking about a 200,000 sq m construction area.” Mr Pickard adds: “To put that into context, the commencement of the excavation to having a watertight box is 20 months.” He concludes: “The next big one is the building envelope, which is scheduled for February 2012. So by then we will have completed the substructure, superstructure and roof. “Yet we only have about 400 people on site, which is perhaps half the amount needed for a traditional job of this kind.” www.cnplus.co.uk