Airport construction presents its own unique set of construction challenges. The structures to be built are often on a grand scale and need to be constructed in a live airport to a tight schedule. The solution to this construction problem is commonly to pre-assemble large structures at ground level, or even off the airport site, and then to transport and erected these heavy structures in carefully engineered operations. DLT has experience of engineering andcarrying out many such operations.
Recent examples of our work include……….
Heathrow Airport, Terminal 5 building and air traffic control tower, UK
DLT were responsible for the detailed erection engineering for the 18,500 tonne steel roof structure of the new main core terminal building, and for a 1000 tonne air traffic control tower. Both were fabricated off-site and erected on-site using strand jack lifting systems. The roof box girders, purlins and cladding to the core terminal building roof was erected in 6 No 2,000 tonne lifts. The control tower was pre-assembled off-site into 7 fully complete modules and then assembled on-site using a unique vertical jacking technique.
Erection system and sequence
Heathrow Airport terminal 5. Erection engineering and heavy lifting using strand jacks.
| The new £3.5bn Terminal 5 at London’s Heathrow Airport is one of the biggest and most complex building projects in recent times in the UK. DLT were responsible for conceptual and detailed design of the erection systems for the 18,500 tonne steel roof of the main terminal building and for the new 1100 tonne steel air traffic control tower. Both structures were fabricated off site and lifted into final position using strand jacks. The main terminal roof was erected using methods more commonly found in major bridge construction. The main roof comprises a series of tied arch steel box rafters with a clear span of 156m, supported on tubular leg assemblies. The leg assemblies are erected first, onto DLT specially designed erection frames, followed by the box rafters. The rafters are assembled at ground level and then lifted to full height in groups of four using strand jacks. Each lift is 2,000 tonnes and is lifted with 16 No 185 tonne capacity strand jacks. The erection frames for the leg assemblies are designed to provide fully adjustable support to each of the leg components and to and skid between erection positions, avoiding the need to dismantle and re-erect. |
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| The Control Tower consists of a 31m high accommodation pod and top mast section, the CAB, supported on a 56.5m guyed mast, total height 87.5m. The mast is stabilised using pairs of pretensions guys attached to the mast just below the CAB structure and positioned at 120º intervals. |
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| The new tower is located adjacent to Terminal 3 and is surrounded by operational aircraft stands and taxiway. To minimise the impact of the airport’s operation an erection concept was developed to construct the CAB off-site before transporting it to the permanent site and lifted it to allow the insertion of the pre-fabrication sections of Mast. | |
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| Once delivered to the final site the CAB was temporarily put down on to the permanent foundation. The temporary steelwork used for the transportation operation was reconfigured and two systems of jacks in open hydraulic circuits were installed between the upper and lower Yoke. These were used to effectively form a structural pin between the permanent structure and the temporary works minimising the forces induced into the permanent works during lifting. Three 16m high Lifting Towers were assembled, one at each corner of the triangular lower Yoke, to support the lifting strand jacks. During lifting, lateral stability of the partially completed Control Tower was achieved by three 180 tonne capacity strand jack operated guys. An additional three 180 tonnes capacity strand jack guys were tensioned to provide additional stiffness to the guying system outside operational weather windows. |
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| The lifting jacks lifted the CAB structure approximately 14m, allowing a section of steel mast to will be installed below. The structure was then put down allowing the lifting system to be reset. This lifting cycle was repeated five time until the final section of Mast was inserted. The completed Control Tower was then lowered onto its permanent foundation and the permanent guys installed. Throughout the lifting operation a bespoke computer controlled system was used to synchronise the operation of the lifting and guying jacks and monitor loads. A separate geo-positioning system was used to constantly monitor the position of the top of the CAB, the lifting yoke and the lifting towers. | |
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HAECO hanger roof lift, Hong Kong
The 2000 tonne steel hanger roof of this maintenance hanger was assembled at ground level in two 1000 tonne units and jacked to full height to save time and money. DLT were responsible for all aspects of the erection engineering for supply and operation of the strand jack system to lift the roof sections. Each roof module was lifted using 9 No DL-S185 strand jacks.
Hanger roof, Chek Lap Kok Airport, Hong Kong. Erection engineering and heavy lift contractor for jacking of roof using strand jacks
| HAECO aircraft maintenance facility erection |
| DLT were responsible for the design, supply & operation of a strand jack lifting system together with all associated erection engineering to lift two 1000 tonne roof structures for the HAECO aircraft maintenance facility at Hong Kong’s Chek Lap Kok airport. The roof sections were assembled at ground level for speed and economy and then each was lifted to full height using nine 185 tonne capacity strand jacks. Once lifted to full height the roof was connected along one side to a reinforced concrete core and released from the jacking system. |
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| Three 300 tonne capacity temporary jacking towers were used, each with two inverted strand jacks climbing up static strands, as shown below. | Lifting adjacent to the concrete core was carried out by three inverted strand jacks housed in tension frames as shown below. |
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Virgin Atlantic Airways hanger roof lift, London
DLT were responsible for the detailed erection engineering for the lifting by strand jacks of an 800 tonne roof truss for this aircraft maintenance hanger at Heathrow Airport. The roof structure was assembled at ground level and then lifted using strand jacks mounted on the top of the permanent columns, which were stabilised by rented proprietary towers that were anchored down to the permanent foundations.---------------------------------------------------------------
Gatwick airport passenger bridge erection gantries, UK
The new airport passenger bridge at Gatwick Airport, UK, spans 128m across a busy taxi way. To reduce disruption to the airport, the bridge was assembled off site, complete with cladding and internal fit out and then transported and erected in a 10 day closure of the taxi-way. DLT were responsible for the detailed design of a pair of 1640 tonne capacity gantries for lifting the completed bridge into final position, weighing 2,660 tonnes. The bridge was lifted using 8 No 410 tonne capacity strand jacks and the gantries were constructed from a modified proprietary jacking tower system.
| Gatwick Airport passenger bridge erection gantries, UK. |
| The new airport passenger bridge at Gatwick Airport, UK, is designed to take 3.5m passengers per year over a busy aircraft taxi-way to the new Pier 6 satellite building. The fully enclosed footbridge spans 128m across the taxi-way with a clearance height of 22m and is supported on two steel pylon structures. The bridge was assembled off site and installed using strand jacks during a 10 day closure of the taxi-way. DLT were responsible for the conceptual and detailed design of the temporary erection gantries required to construct the bridge. | |
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| The bridge superstructure was fully assembled at ground level in a temporary construction area 1.5km from the site. The central 175m long section weighed 2,185 tonnes, including the steel frame, composite floor, roofing system, glazing and services. The two erection gantries were assembled around the bridge superstructure in the temporary construction area and then load tested to 115% the maximum lift weight using the self weight of the bridge and the temporary assembly foundations. The gantries were then used to lift the bridge superstructure 1.5m to allow self propelled modular trailers (SPMT's) to be positioned under the bridge. The bridge and gantries were then transported together across the airport to the final location on the SPMT's. The gantries were then lowered onto prepared foundations ready for lifting the bridge. Eight 418 tonne capacity strand jacks mounted at the top of the two gantries were then used to lift the bridge to approximately 2.4m above final level to allow installation of the pylons beneath. The two pylons were hung from the underside of the bridge and the complete assembly, weighing 2,660 tonnes was then lowered by the strand jacks onto the permanent foundations. The gantries were then dismantled and removed from site. | |
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Source: Dorman Long Technology
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