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Hünnebeck formwork at major German airports

Infrastructure projects a challenge for expertise-driven formwork solutions
Formwork competence in airport construction

There are a number of major German airports currently being either built or expanded and in all these cases Hünnebeck is well represented with its sophisticated formwork solutions. This German company based in Ratingen is designing and supplying self-climbing formwork (SCF) for the two over 70 meter tall new towers of Deutsche Flugsicherung in Frankfurt and Berlin. The north and south piers at Berlins new BBI airport are also being built with Hünnebeck formwork. The Company has already supplied the Leipzig/Halle airport with sophisticated one-off formwork for building the abutments of Europe’s longest taxiway bridge.

Self-climbing formwork for the Frankfurt tower

It was especially the high load-bearing capacity and hence the possible platform widths that persuaded contractors Ed. Züblin AG to opt for Hünnebeck’s self-climbing formwork when constructing the new 72 meter tall Frankfurt tower. Since the individual brackets of this modular shuttering unit have a vertical load capacity of up to 150 kN, the same platforms can be used in the construction of the 12 x 11meter tower cab floor as had been employed as working platforms for the self-climbing formwork. This saves time and dispenses with hazardous assembly work at great heights. The slab formwork is mounted directly on the platform as a preassembled table complete with side protection.
With their high load-bearing capacity, the SCF brackets offer additional construction advantages on the Frankfurt site both in terms of cost efficiency and safety. Mounted on the SCF platform is a concrete-bar setting scaffold (Bosta 100 frame scaffold) with three tiers or levels. This strategy allows the next cycle to commence immediately after pouring and bar-setting work. Also, the extra-wide platforms can be used as working platforms in assembling the steel structure for the tower’s technology and crisis rooms. In use in Frankfurt is self-climbing formwork with eight brackets and two finishing platforms. Two of the four working platforms measure 9.8 x 3.6 meters, the others 9.8 x 4 meters. Wooden beam formwork integrated into the SCF design ensures through the special form lining the necessary quality of the fair-faced concrete surfaces (SB 2). The formwork can be lowered by about 90 cm for convenient bar-setting and cleaning work.

In the construction of the four interior shafts (1 x 4 metres; 2.7 x 2 meters; 1.7 x 1.75 metres; 0.8 x 1.75 metres) the innovative shaft corners taken from the MANTO range of large-frame formwork helps to speed up work. The lift rate is up to 5.4 meter high at a speed of maximum 12 meters/h. Two brackets make up a single climbing unit.

The SCF strategy devised for Frankfurt airport ensures a high degree of safety during the disassembly phase, too. On completion of the tower cab, the platforms cannot be conventionally extracted with the aid of a C-hook. As a consequence, they first descend from the building to a height at which a small truck-mounted crane can disengage the platforms and carry them safely downward. This is a technique that has already proven itself in the construction of the Düsseldorf control tower.

The two-storey low-rise building which an adjacent part of the tower, it is also being built with the aid of Hünnebeck formwork systems; Manto large-frame formwork for all the walls and Variomax wooden beam formwork teamed with ID 15 frame props for producing the slab surfaces.

Formwork solutions for the new Berlin airport.

A similar SFC strategy is also being adopted in the construction of the control tower at Berlins new Berlin Brandenburg International Airport (BBI). The contractor here is once more Züblin. In its basic dimensions, it has so much in common with the Frankfurt tower that the two share many of the formwork solutions. The top section of the Berlin tower, however, will have a fronted, cantilevered reinforced concrete stairwell to be built in one cycle together with the tower. This is a challenge for which SCF can again provide a cost-efficient solution thanks to its high load-bearing capacity and ample platform width. The formwork for the three-storey low-rise building is once again supplied by Hünnebeck.

For the mega construction site of the BBI airport Hünnebeck is also providing on behalf of the BBI consortium (Max Bögl & Alpine) the formwork for the 350 meter south pier with its ten passenger-boarding bridges and the north pier (same length) with its twelve walk-boarding accesses. The following parts will be constructed from in-situ concrete: the foundations, the frost skirting, cable ducting, the soffit slabs, a variety of wall surfaces, pillars, and joists. Supplementing the in-situ concrete are a number of pillars and joists constructed from prefabricated concrete.
On this particular construction site the challenge was posed not by the geometry of the parts but by the very short period available for building the shell and the limited on-site storage space. This is a situation that calls for formwork that can be relocated and transferred very quickly. An example of such a system is Manto large-frame formwork that allows complete wall sections to be transferred (up to 40 m² in a single crane lift). Another useful resource is the new table form Topmax (2.40 x 5.40 meters and 1.80 x 5.40 m) which, with its 12 cm flat steel frame and plastic form lining is not only highly economical in terms of storage and transport space but has the added advantage of very short shuttering and transfer times. These benefits accrue from the full lineup of system solutions for protection against falling from height, overhangs, projections, infill and compensation areas, and full compatibility with other Hünnebeck table systems. The outcome: cost and time savings by dispensing with special solutions. The Topmax tables connected by a centering tool can be moved and repositioned in large sections, in fact 26 m² with a single lift of the crane. These are slab construction time- and cost savings that on the Berlin site are becoming evident within a very short time.

Another factor contributing toward a short shell construction time of five to six months per pier was the detailed on-site assistance available. Hünnebeck is not only providing a master shutterer to give on-site hands-on advice; a technical project team that has mapped out the shuttering solutions is available throughout the construction period and is closely involved in the shuttering process itself. Together with those working on site, Hünnebeck has developed a detailed implementation program that is continuously monitored during the construction process and can be repeatedly modified to match any sudden requirements through readily available material arrivals and departures. The outcome of these closely detailed shuttering plans: perfect coordination and optimization of on-site supplies. As a consequence, the in-situ concrete parts comprising the north pier, which would start construction in April, is very likely to be completed on time in August. This will be followed by the work on the south pier.

Leipzig/Halle airport: one-off formwork for the taxiway bridge

Quite different formwork challenges were posed in the construction of a new taxiway bridge at the Leipzig/Halle airport in Germany which is currently being expanded into an air freight hub: 191 meters in length and 63 meters in width, this is among the biggest of its kind worldwide. The 8-field structure serves as an additional taxiway for aircraft between the north and south takeoff and the landing runways. The bridge straddles a motorway, an ICE rail line, and a trunk road. Whereas its superstructure largely comprised prefabricated parts with cross-girders from in-situ concrete, the substructures especially the two abutments, called for some special formwork. For this purpose, Hünnebeck developed and fabricated the necessary wooden beam formwork. Hünnebeck’s location for special formwork construction in Irxleben, eastern Germany, delivered to the site ready for use assembled formwork designed for employment in the construction of the two abutments. This one-off solution was made up of the following components:

• 1,110 m² formwork elements made up of 24 cm props, preassembled to wall height with timber-planked textured fair-faced concrete surfaces;
• Just under 220 m² of special elements from the GF 20 large-area formwork range for shuttering the running joints, the wing walls and the services passage;
• About 60 continuous meters of ID 15 stationery shoring with overlying soil-side recess boxes;
• 8 meter tall brace frames for the initial single-sided shuttering of the running joints.

Complementing this special formwork were further system components from Hünnebeck’s product range: to prevent falls from height, Protecto system parts were used; Bosta 70 frame scaffolding as working and protective scaffolds and for aligning the formwork, the two-end telescoping aluminum self-aligning strut Super 10 (load capacity of up to 25 kN).