International Site Review 1/2002
Rapid progress with Doka
M2 Medway bridge, Kent, UK
Kent: M2 Medway Bridge
Mauritius: Midlands Dam
rapid progress
with cost savings Page 3
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Atlantic City: Harrah’s Extension
Berlin: Olympic Stadium
in only 7 months
fair faced concrete
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Editorial
Formwork News 1| 2002
Looking through this latest edition of Formwork News, you’ll be able to inform yourself on a number of very interesting forming assignments where superb results have been achieved worldwide with the aid of Doka formwork systems and planning work. Particular attention should be drawn to the forming assignments on the Medway Bridge in Kent, UK, and (with composite superstructure formwork) on the Havel Bridge in Germany, and to the climbing-formwork assignment on the towers of the Vistula Bridge in Poland. The use of Doka automatic Werner Haring climbing formwork on the 26-storey Harrah’s Hotel and Casino Extension in Atlantic City, N.J., USA is also worthy of mention. However, the high-quality results achieved on these and many other projects are only possible using modern formwork systems which are available at short notice, and with efficient formwork planning. Here, only a dependable and capable formwork partner can possibly fulfil all the essential requirements that must be met if in-situ concrete construction is to proceed smoothly and successfully. In today’s competitive situation, it is vital to locate – and utilise efficiently – all possible rationalisation potential in construction operations. It is a proven fact that even today, with the right formwork system, optimum formwork service and a capable formwork partner, significant cost-reductions are possible on construction sites. It is not only on major projects, however, that innovative formwork ideas are to be found. Many of the articles in this edition show excellent examples of construction companies and formwork engineers working together to develop very efficient cost-saving formwork solutions. We know, and know well, that formwork-related services are becoming an increasingly significant factor in day-today construction operations. This is a challenge that we respond to with combinations of products and services that are tailor-made for the construction project in question.
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Werner Haring Chairman of Doka Group Management
During pouring, the elements of the outside formwork are anchored to the forming carriage. For repositioning, the elements are simply lowered.
Havel Bridge in Plaue, Germany:
Step by step … … a well-planned cycle sequence e.g.: in the bridging of the River Havel: In Plaue, just west of the town of Brandenburg, a 240 m long steel composite bridge is being built across the River Havel. The contractor is Porr Technobau of Berlin.
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or structural design reasons, the 13.0 m wide concrete carriageway cannot be cast progressively working from one end towards the other. This means that rapid repositioning of differently sized sections, along the entire length of the bridge, was called for here. The “traffic manager”, foreman H. Bähr, came up with a valuable timesaving idea: Using just one centrally positioned chain, it was possible to shift 80 tonnes of weight. Without having to adjust between left and right towing devices, either when advancing or reversing – which saves Easy repositioning of the formwork has ensured that construction can move ahead swiftly.
time in the “back-step” sequence. After all, there was a distance of 75 m to cover between each of the pouring cycles. Thanks to the well thought-out Doka systems, repositioning (i.e. moving the carriage forward or back) took only a few hours each time. “We are most satisfied with the results that have been achieved. Working together with project manager Carsten Beer and Doka field officer Thomas Schneider, it was possible to optimise the forming carriage for our particular project so that we could use it in just the way that we had in mind” says site engineer Thomas Thiel. ■ Contractors: Porr Technobau
New motorway bridge across the River Medway:
Rapid progress with Doka A 17 km stretch of the A2/M2 motorway route between London and the Kent coast is currently being widened. This has necessitated the building of a new bridge across the River Medway, at the western end of the widening project. The new Medway Bridge will be completed by the summer of this year, using Doka formwork. It is located between the existing M2 motorway bridge and the recently completed railway bridge built as part of the Channel Tunnel Rail Link. Britain’s Highways Agency awarded the construction contract for this £ 20 m (€ 33 m) bridge project to the “CSM Joint Venture” of Costain, Skanska and Mowlem. he balanced cantilever works, to be carried out on the river spans of the bridge, comprise the construction of 16 sections of superstructure, of varying heights and lengths, on either side of each of the Medway Bridge’s two river piers. The Doka formwork for this was designed in such a way that it can adapt to continuous reductions in the section height. Over 20 m wide to accommodate 4 lanes of traffic, the bridge superstructure has a section height of 10 m at the piers, which tapers to nearly one third of this height (3.50 m) by midspan. While the heights of the superstructure sections progressively decrease, their lengths increase from 3.10 m to 6 m towards midspan, to make optimum use of the load-bearing capacity of the cantilever construction traveller and to speed up the progress of work. The tensile stresses occurring in the cover slab of the superstructure during the construction stage, and in the soffit slab following completion, are sustained by post-tensioned cables anchored to concrete corbels. For these prismatic tensioning anchorages in the soffit slab and cover slab, Doka offered a simple – yet efficient – formwork solution which enables the formwork to be erected and struck without difficulty, and to be quickly repositioned. This solution had to allow for the fact that the external post-tensioned cables have to be installed after concreting, but before the formwork is struck.
The superstructure is finally completed with the casting of the edge beams along the outer edges of the cantilevering cover slab. This was done in a highly streamlined manner using Doka edge beam forming travellers. The concept for the superstructure formwork was developed by Doka in close collaboration with the contractors CSM Joint Venture (Costain, Skanska & Mowlem) and
WITO, who were responsible for the design of the balanced-cantilever works. This made it possible – despite the difficult nature of the task – to elaborate a highly efficient formwork scheme which enabled work to progress smoothly and swiftly. ■
Contractors: CSM JV (Costain, Skanska & Mowlem)
The completed bridge superstructure will have a clear span of 152.5 m between the piers and will be 30 m above water-level.
Formwork News 1| 2002
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3 Doka edge beam forming wagons coupled together to make a traveller.
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The elements of the outside formwork, each measuring 170 m2, are pulled forward on the launching girder, on both sides simultaneously.
Austrian cut-and-cover tunnel being cast monolithically A 2.3 km long twin-tube tunnel with 2 lanes per tube is currently under construction for Austria’s A8 autobahn in the Aiterbach Valley near Wels, in a weekly cycle. Because the cut-and-cover tunnel stands in groundwater, it is being built as a “white tank”, meaning that its foundation, walls and cover slab have to be cast monolithically (i.e. in one single pour).
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Formwork News 1| 2002
he contractors, Strabag Bau AG, required not only the shortest possible cycle sequence during pouring, but also comprehensive mechanisation of the formwork in order to save on labour. Between them, the Strabag staff in charge of the planning work and the Doka Formwork Experts from Amstetten came up with the ideal solution:
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All these actions are initiated from a central control unit – e.g. tilting up the haunched elements in the floorslab/wall transition zone, or retracting the wall-formwork elements when striking the formwork. In only 5 working days, all the operations needed for one entire section – including striking, advancing, formwork erection and pouring – have been completed.
Two Doka travelling formwork carriages, working from the middle of the future tunnel towards either end, each allowing a small crew to pour 24 m long sections. In this way, a total of 48 m of tunnel can be completed every working week. It will take a total of 50 cycles towards one end of the tunnel, and 50 cycles towards the other, to complete the full length of the tunnel. Each of these cycles runs according to the following schedule: Every Friday, the two huge launching girders suspended in the portals of the inside
formwork are hydraulically advanced by the length of one section. The reinforcement is now placed for the floor of the next section.
On the Monday, the concrete has cured sufficiently for the formwork to be struck. Once again, the central hydraulic control unit is used for repositioning the outside formwork. Then the inside formwork is put into the travelling position, and the 63 cm haunched elements on the base slab are tilted up out of the way. The tunnel-tube on the inside of the curve is the first to be repositioned – an area of formwork measuring 510 m2 and weighing 150 t is now moved into the new position. Every Tuesday, the centre-wall reinforcement is completed. The reinforcement for the outside walls is placed after the second half of the inside formwork has been pulled forward. On the Wednesday, the finishing touches are put to the reinforcement and the form-ties. On the Thursday, approx. 1000 m2 of concrete has to be poured within around 14 hours. ■ Contractors: Strabag
48,000 m3 of concrete for the Midlands Dam on Mauritius:
Precisely co-ordinated formwork saves (transport) costs: The brief given to the formwork planners for the spillway on the Midlands Dam is actually one that is relevant for any site: To use only as much formwork as strictly necessary. This is particularly true of sites at remote locations, where transport costs for materials and equipment play a not insignificant role.
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his dam project necessitated many and frequent adaptations. Starting with the huge floor blocks, then in the rising sidewalls and the centre pier, right the way through to the blocks of the spillway with its inclined surfaces. Careful, thorough planning is particularly worthwhile in a case like this.
All the supports – both the supporting construction frames and the D22 brackets – followed the grid pattern of the formwork elements. The cornerstone of this versatility was the well thought-out grid of the formwork elements.
Doka dam formwork and Doka folding platforms K were used alongside (and behind) one another – the former without through-ties, the latter as a tied wall formwork.
The use of Doka large-area formwork Top 50, in lengths of 3.00, 4.50 and 6.00 m, provided a uniform spacing for the supporting construction frames used on the starter blocks, and for the bracket and anchor spacings in the “climbed” pouring-sections. The formwork was designed for block heights of 3.0 m and a concrete pressure of 35 kN/m2. For this reason, the supporting construction frames for the founda-
tion blocks were also fitted with Doka dam formwork D22 components. This made it possible to continue raising the sidewalls and the centre pier with dam formwork D22, seamlessly and without through-ties. The stiffening buttress walls in this zone were, however, executed with through-ties, using the Doka climbing formwork K as a scaffold unit. The formwork elements were always the same, which permitted large numbers of repeat uses. This, in turn, made for low total quantities of formwork – and low costs. Within the next 36 months, the 2450 m long earth dam will also be finished. Covering an area of 300 ha, up to 25.5 million m3 of water will then be available for irrigation and potentially also for processing into drinking water. ■
Contractors: DTP Terrassement - Bouygues TP J.V.
Formwork News 1| 2002
And here is what it led to: For the approx. 48,000 m3 of concrete involved here, the contractors used only 1750 m2 of formwork – helped by an exact utilisation plan which minimised down-time for the formwork and scaffolds.
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Brazil:
Tough formwork challenge T Site: VD 7 viaduct, Brazil Contractors: Consórcio Imigrantes - JV CR Almeida (Brazil) & Impregilo (Italy)
he 1.25 km long viaduct VD7 on the 16 km long “Segunda pista da Rodovia dos Imigrantes” expressway in Brazil is being built using Doka climbing formwork 150 F for the pier shafts and Doka large-area formwork Top 50 for the pier-heads and carriageway decks, and with a free-cantilevering carriage with a capacity of 120 tonnes. ■
Singapore:
On schedule, and within budget U
sing Doka wall and floor-slab formworks, the two 18-storey administration buildings for the Singapore Port Services Agency were completed in an exceedingly short construction period of only 12 months. This was made possible by the use of Doka large-area formwork Top 50 for the walls and columns, and of Doka load-bearing towers d2, of which a sufficient quantity was commissioned for one-and-a-half times the area of each floor. ■
Site: Port Services Agency, Singapore Main Contractor: Samsung
Portugal:
Formwork News 1| 2002
One cycle every 8 days
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oka supplied formwork for the Perna Seca viaduct on the A2 motorway “Auto-Estrada do Sul” in Portugal. A 60 m long trussed box section with swivel side drop panels served as a launching girder on which – in a 2nd operation – Top 50 formwork was mounted on top. ■
Site: Perna Seca viaduct Contractors: Contacto, Ecop, Somec e Gabriel Couto
World site round-up Lebanon:
A comprehensive assignment W
ork on the shell of the Hajj Bahaeddin Hariri Mosque was recently completed with the forming operations on the dome, which has a diameter of 25 m and a clear height of 35 m. All the in-situ concreting works, including the two minarets, were performed successfully using Doka formwork equipment. ■
Site: Hajj Bahaeddin Hariri Mosque, Lebanon Contractors: Betabat
Ireland:
Staxo: simply better T
he ease and simplicity with which the Staxo loadbearing tower can be erected and dismantled were greatly appreciated by subcontractor McNally Brothers on its bridge construction site at Batter Lane, Swords, Co. Dublin, on Ireland’s Northern Motorway. In order to speed up operations, each of the load-bearing towers were pre-assembled on the ground before being lifted into position by crane. ■
Site: Bridge on Northern Motorway at Batter Lane, Swords, Co. Dublin. Main Contractor: Siac Construction Subcontractor: McNally Brothers
Dubai:
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he 43-storey, 250-room Shangri-La Hotel is currently under construction in Dubai. Doka has supplied this project with 66 automatic climbers SKE 100, which “climb” the outside of the façade and carry a rising scaffold. Both the outside and inside formworks (assembled from large-area formwork Top 50) are suspended from this scaffold. ■ Site: Shangri La Hotel, Dubai Contractor: Al Habtoor Murray & Roberts JV
Formwork News 1| 2002
Formwork handling made easy
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Atlantic City:
Harrah’s Extension finished in only 7 months Thanks to an optimised formwork concept, it was possible to complete the shell of the 26-storey Harrah’s Hotel and Casino Extension in Atlantic City, New Jersey, within a mere 7 months.
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he walls of the lower storeys are rather higher and were formed – highly efficiently – with large-area gangs of Framax framed formwork. And Top 50 large-area formwork, which was delivered to the site pre-assembled, did a superb job on the outer façades of the end walls, and on the lift shafts and stairwells. The outside walls of the 2.90 m high typical floors were raised using 24 automatic climbers SKE 50.
For the opposing formwork on the inside, and for all the columns, easy-to-handle Alu-Framax panels were used, as the 15 cm thick in-
As the floor slabs had already been cast, the remaining formwork had to be struck by hand – a task for which the lightweight Alu-Framax panels proved highly advantageous.
situ concrete layer with which the planned filigree floors were to be covered had to be poured “in one go” along with the walls and columns. For this reason, it was not possible to strike the formwork from the walls and columns until after the floor slabs had been
poured. What is more, this had to be done without any assistance from the crane. With the lightweight 60 cm wide Alu-Framax panels that were used here by the contractors, FABI Construction, this was no problem to accomplish. The formwork concept elaborated by Doka’s US representatives Conesco, in collaboration with contractors FABI Construction, enabled an average forming cycle of one week per typical storey. This made it possible for the shell, on which work had commenced only in May 2001, to be completed by the end of 2001.
Formwork News 1| 2002
No wonder, then that General Superintendant Hugh McCarron was so satisfied with how all the forming operations had gone, and that this success convinced FABI President and owner Al Zappone to purchase the Alu-Framax, Top 50 and MF 240 equipment from this project for use on his next project in Atlantic City. ■
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Contractors: FABI Construction, New Jersey
Doka automatic climbing formwork in action on the exterior façades of the 90 m tall Harrah’s Hotel and Casino Extension.
Amsterdam:
Formwork and concrete placing boom “in one go” HBG Utiliteitsbouw had been awarded the contract to erect a 19-storey, 79 m tall office tower in the centre of Amsterdam. In order to be able to meet the tight time deadlines, it was decided – in collaboration with Doka Nederland and Doka T&S Amstetten – to use Doka automatic climbers SKE 50 and SKE 100.
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he core and outside walls of the entire structure were formed with automatic climbing technology, in 21 cycles. In order to achieve the most efficient cycle possible, no account was taken of the heights of the storeys themselves. The layout of the office tower corresponds to an elongated rectangle enclosing a narrow inside rectangle, and with three projecting walls.
Using Doka automatic climbers, things moved upwards in the following regular cycle: ● The SKE 50 automatic climbers lift one shaft formwork element upward. Work begins on placing the reinforcements. ● The entire outside formwork now follows. The central control unit is connected to all the automatic climbers via a circular tube (ring main).
The pouring cycles were all kept the same size; this, plus the precision climbing sequence, ensured that work progressed rapidly.
This ensures that climbing takes place uniformly and smoothly. ● Work on placing the reinforcements is finished. The gap to shaft 1 is closed. ● The concrete placing boom “hitches a ride” with the final lift of the automatic climbers SKE 100, thereby arriving at the top at the same time. The boom stands on an integral grillage, and thus needs no separate platform of its own. This in turn saves an extra lift and means that the boom can be made considerably shorter. Higher manoeuvrability and appreciable costsavings are the result. In this way, by taking account of all the issues involved, this cycle sequence made it possible to meet the tight deadlines imposed here. ■
The elements are lifted one at a time, in line with the progress of the reinforcement work. This picture clearly shows the generous room for manoeuvre that is left for these operations.
Formwork News 1| 2002
The formwork area, totalling 530 m2, was designed and broken down accordingly; it consisted of 13 elements to be moved, on nine Doka climbing platforms MF 240 and three shaft platforms. For formwork erection and removal, the elements were advanced and retracted with the Doka travelling unit MF 240. Where space was tight, the wall formwork was suspended from a steel support construction. In this way, it was possible to lift the formwork without using a crane in these situations as well.
Contractors: HBG Utiliteitsbouw
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New Oil Sector Complex, Kuwait:
Complex logistical challenges The new joint central administration complex of the Kuwaiti Oil Ministry and the Kuwait Petroleum Corporation comprises two high-rise structures. One of these is 17 storeys tall and the other 21 storeys tall. There is also a third tower with a semi-elliptical cross-section that houses the stairwell and lift shafts, and from which access is provided to the two office towers via aerial walkways. In addition, a 5500 m2 podium - a singlestorey and two-storey low-rise structure - is being built:
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Formwork News 1| 2002
he contractors, a joint venture of Alghanim International and LG Engineering, are building this administration complex using the whole spectrum of Doka equipment, and with wide-ranging Doka planning assistance. Office Towers A and B each contain two cores, consisting of stairwell and lift-shaft groups. These cores are “climbed” two
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storeys ahead of the floor slabs, making it possible to “de-link” operations on the vertical and horizontal parts of the structure and thus saving construction time. For the outside walls of the triangular zone of the office towers, a complete set of outside formwork has been commissioned, and for the inside walls, a one-half set which is shifted once per storey.
Doka not only supplied all the formwork systems, but also provided comprehensive scheduling to go with it.
The outside formwork of the walls also serves as the perimeter formwork for the floor-slabs. The floor-slabs follow in a fortnightly cycle, with sufficient formwork equipment for two complete storeys being commissioned for each of the two office towers. A total of approx. 5600 m2 of Dokaflex 20 is in use. In the areas that are open to the outside, d2 tableforms are used, for safety reasons. The walls of the semi-elliptical stairwell and lift-shaft core are also “climbed ahead” in their entirety. The floor-slabs and aerial walkways to the two office towers follow approx. two storeys behind. Some 650 m2 of large-area formwork Top 50 is in use here, together with climbing formwork 150 F with trailing platforms and shaft platforms. Here too, work is proceeding in a weekly cycle. It has taken very extensive planning work by Doka Kuwait to master the complex logistical challenges presented here. The project also calls for intensive on-site presence and assistance from Doka, which has been greatly appreciated by the site engineers. ■ Contractors: Alghanim International – LG Engineering
Doka carried out extensive planning work to master the logistical challenges.
Warming up hall for Berlin Olympic Stadium:
Fair-faced concrete with Doka Dating from 1936, the Berlin Olympic Stadium is being altered and renovated in keeping with its status as a listed monument – all the time alongside ongoing use of the stadium. By 2004, it will have been upgraded into a modern event arena, not least for the finals of the football World Cup which Germany is to host in 2006.
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n January 2002, work got underway on the building of a new, two-storey “warming-up hall”: With lorry parking spaces and technical service installations in the approx. 5 m high sub-basement level, and a 4.60 m high warming-up hall for the sportsmen and sportswomen in the basement level. The 96 m long and 35 m wide reinforced concrete structure is built entirely underground, under a 40 cm cover slab. After completion, the structure will be completely hidden from view beneath a large area of lawn. Framed formwork Framax was chosen to achieve fair-faced con-
crete surface with the specified formwork pattern. In this connection, the Doka Formwork Experts co-operated with the contractors and the planner to recommend suitable formwork stacking configurations, which had to be approved by the client.
Floor beams shored by Staxo loadbearing towers.
For important key locations, this was done with reference to elevation plans which explained the proposals. 380 m2 of Framax framed formwork – newly faced with form-ply for use on the fair-faced concrete walls – ensured that forming operations
Framax for fair-faced concrete.
proceeded smoothly on the walls. This formwork was supplemented by 135 m2 of newly re-faced circular formwork H 20 for the curved sections of the supply tunnel. The 30 cm thick floor between the two basement levels is punctuated at regular intervals by floorbeams with a cross-section of 110 x 80 cm and with steel girders on the inside. 1500 m2 of Dokaflex 1-2-4 with rented Dokadur panels serve as the floor-slab formwork, and the floor-beams are shored by Staxo load-bearing towers. ■
Austria: Österreichische Doka Schalungstechnik GmbH A 3300 Amstetten, Reichsstrasse 23 Phone: +43-7472-605-0 Fax: +43-7472-64430 E-Mail:
[email protected] Germany: Deutsche Doka Schalungstechnik GmbH D 82216 Maisach, Frauenstrasse 35 Phone: +49-8141-394-0 Fax: +49-8141-394405 E-Mail:
[email protected]
UK: Doka UK Formwork Technologies Ltd. Monchelsea Farm, Heath Road Boughton Monchelsea Maidstone, Kent, ME17 4JD Phone: (01622) 74 90 50 Fax: (01622) 74 90 33 E-Mail:
[email protected] Ireland: Doka Ireland Formwork Technologies Ltd. Tinure Industrial Complex Monasterboice, Drogheda County Louth Phone: (041) 68 61 620 Fax: (041) 68 61 525 E-Mail:
[email protected]
USA: Conesco Industries Ltd. 214 Gates Road Little Ferry, New Jersey 07643 Phone: (201) 6 41 65 00 Fax: (201) 6 41 62 54 E-Mail:
[email protected]
For the Doka address nearest you, please see our web-site: http://www.doka.com, or phone or fax Doka in Austria or Germany.
Formwork News 1| 2002
Dokaflex 1-2-4 serve as the floor-slab formwork, and the floor beams are shored by Staxo load-bearing towers.
General contractor: Walter Bau in concert with Dywidag, Augsburg Forming operations: Bold GmbH & Co. KG Baubetriebe Berlin
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“Most Siekierkowski” bridge across the Vistula in Warsaw:
Making optimised use of formwork leads to efficient construction sequences A new 830 m long cable-stayed bridge is being built across the River Vistula just south of Warsaw’s Old Quarter, with twin towers to support and stay its 33 m wide carriageway deck, which has a 250 m span. The contract to supply the formwork for the two slender, 92 m tall bridge-towers went to Doka Polska.
Formwork News 1| 2002
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orming bridge-towers such as these cost-effectively is a fascinating challenge: Massive springers, inclined towards the outside at an angle of 75° to the perpendicular and conically tapering as they rise. Then, at a height of 12 m, a prestressed concrete cross-beam to support the carriageway decks. Above this, two slender piers: Up to a height of 62 m, these are hollow boxes and are inclined inwards at an angle of 7°; above the 62 m mark, they rise exactly in the perpendicular. At the kink in the piers at a height of 62 m, there is a second cross-beam.
Remarkably small quantities of equipment, most of it from the standard product range – this is the secret of optimum cost efficiency here. In order not to have to use
heavy special profiles on the piers (which had to be formed without using form-ties), the walings of the Top 50 elements were stiffened with trusses. One set of springer formwork, assembled from Top 50, was used to form the bases of all four piers in succession. Four sets of Top 50 formwork were then “climbed” on MF 240 climbing platforms to form the four rising pier shafts, in 17 casting sections up to the finished height of 92 m. All this was done with only a very few crane cycles and – in the inclined sections – with a special overhang lifting unit, supplemented by a single-sided inside formwork in the hollow-box zones. The four sets of formwork continued to be used without any modifi-
cation above the top kink, where a 27 m long hollow steel profile had to be embedded inside each of the pier shafts. The Top 50 formwork for the bottom cross-beam rested safely on a truss made of 20 tonnes of steel profiles, which was used a total of four times: First for the two bottom cross-beams, and then for the two top ones. As the exemplary concept employed here clearly shows: With good planning, even out-of-the-ordinary challenges can be mastered both economically and in record time. ■
Contractors: JV of Mostostal Warszawa S.A., WARBUD S.A and Campenon Bernard SGE