STUTTGART 21 CONSTRUCTION PROJECT, ED. ZÜBLIN AG
Follow actual progress with the construction work on the Deutsche Bahn AG information webpage - Mediathek Bahnprojekt Stuttgart-Ulm
(© Ed. Züblin AG)
(© Deutschen Bahn AG)
(© Deutschen Bahn AG)
UP TO OKTOBER 2018
The tower units now with their wooden formwork pieces in position stand between the chalice structure and the covered chalice foot. Without the aid of a crane, these towers were lowered and moved to the side unproblematically in a very short time using the especially developed heavy-duty platform carriage.
ROBUSTA-GAUKEL supplied special templates for the complicated reinforcement configuration at the transition point from the chalice to superimposed hood. The prefabricated reinforcement cages were hoisted in by crane using these templates, which are painted in different colours for the various areas. They will remain installed until the reinforcement work has been completed so that positioning is secured on an ongoing basis.
Formwork pieces for the covering formwork
These pictures illustrate the formwork pieces for the covering formwork. They are divided up into 30° strips like orange peel and still have to be screwed together with special braces before being set in position on the reinforcement. ROBUSTA-GAUKEL undertook the design engineering and manufacture of these braces in a similar way to the specially developed rotating and transportation device for safely moving and turning the extremely heavy formwork parts with one piece weighing up to approx. 4.5 tonnes.
UP TO AUGUST 2018
The first stage will see the chalice foot concreted up to the 6 m level. This chalice foot will then be shielded with a specially designed protective cover, as with a cape, until subsequent formwork can be set up for the chalice as part of the roof structure. This means that the facing concrete surface is safely protected from contamination and rust marks.
An impressive sight: the lower scaffolding has been completely fitted out with formwork for the “Randkelch”. This scaffolding is composed of up to 75% of the towers from the “Regelkelch” itself. The circumferential working platform fastened to the upper towers can be removed if necessary. At the picture’s right-hand edge, there is a separate scaffolding tower built up with office containers. Steel fixers can find information here directly on site about the complicated reinforcement configuration using an interactive 3D model at a PC terminal. The reinforcement for the “Randkelch” is made up of approx. 11,000 positions!
UP TO JULY 2018
In July 2018, work was commenced on stripping the formwork. The first external tower segment was slowly lowered at a 30° angle with the aid of a special carriage and withdrawn with great accuracy. The upper tower initially had to be lowered to an angle below 45° with the aid of built-in hydraulic cylinders so that the formwork could be stripped from the interior tower segment. It was only then possible to move the whole tower unit on the carriage.
Once 2 temporary supports had been installed in the 30° segment, the towers were fitted out in the adjacent segment section.
Concreting the “Restkelch” superstructure:
Everything was ready on 30th June. The first “Restkelch” superstructure was concreted. Approx. 460 m³ concrete were installed with 2 concrete pumps in about 6 hours – 200m³ alone in the two last hours!
Scaffolding has in the meantime been erected completely around the first “Randkelch”. Its elaborate reinforcement was installed whilst other work on the “Restkelch” was being carried out. Once the formwork towers with their complex timber formwork had been set up and aligned, more than 160 tonnes of reinforcing steel were installed!
SINCE END OF FEBRUARY 2018
The first “Randkelch” - reinforcement work
JANUARY – FEBRUARY 2018
The first “Randkelch” – setting up formwork
SEPTEMBER – NOVEMBER 2017
The first "lower" towers are set up around the chalice foot.
A heavy-duty platform carriage was developed purposely for transferring and moving the extremely heavy tower units without a crane. This carriage has additionally been equipped with 4 swivelling lift cylinders, which were flange-mounted on its sides in different positions, making it possible to adapt the cylinders’ position to the varying tower shapes.
After the test set-up it was then possible to supply the first elements. The first galvanised tower units were assembled on 22nd August at the construction site. Supervisors from ROBUSTA-GAUKEL and Villing were on site in an instructive and supportive role.
First picture: The first tower built up of 3 truss girders has already been mounted complete with all diagonal struts. This will later support 1/12 of the outer wooden formwork with bracing belts screwed in underneath. The fan-shaped arrangement can be clearly recognised, already giving a hint of the circular chalice-like layout.
Second picture: Immediately following this, the working platform (still without a wooden covering) was secured in place.
Picture left: Assembly work continued on the inner lower tower in the afternoon. Its size is impressive, taking into consideration the fact that the final support height has not yet been reached, since another tower will be erected on top.
Formwork scaffolding test set-up
In brilliant sunshine, the first 30° segment of the formwork scaffolding for the characteristic chalice columns of the future Stuttgart railway station was built up for testing purposes.
Approx. 20 tonnes of steel were installed on a base area of approx. 8.20 m x 14.0 m with a height of up to approx. 11.0 m in order to absorb the forces generated during the concreting process.
This test set-up worked out to the complete satisfaction of the site management as well as the design engineers and others involved.
The components were subsequently dismantled and galvanised for optimum protection during the entire construction time. This makes it possible for them to be utilised unproblematically on a permanent basis for the many years the construction work will take.
Shortly afterwards, a total of 12 such segments was delivered to be assembled as the full and final scaffolding for the chalice column formwork with a diameter of more than 30 metres.
The time had come after exhaustive planning… The first chalice foot had been successfully cast in concrete. The following ROBUSTA products were employed in this work:
Special bracing belts made with HEB beams
The complete formwork was put together from 4 timber elements. These were then “wrapped round” like a barrel with the bracing belts – structural computations and manufacture by ROBUSTA-GAUKEL – to counter the inner hydrostatic pressure.
Self-propelled special heavy-duty carriage
This was manufactured specifically for this construction project and was additionally equipped with 4 lifting cylinders flange-mounted at its sides on the frame. These special cylinders, each with 10 tonnes load-bearing capacity, are installed on telescopic arms that can also swivel sideways so that the scaffolding towers for the lower chalice formwork can be moved without a crane.
Special lifting mast on the heavy-duty carriage
It is not possible to set the chalice foot formwork elements in place by suspending them from a crane on site on account of the reinforcement projecting from the side above. A special lifting mast was designed, structurally computed and produced by ROBUSTA-GAUKEL for the purpose of transporting single formwork elements independently of a crane. The lifting mast was bolted onto the carriage’s front side; two of the swivelling cylinders were utilised for hoisting and lowering.
We would also like to thank our partners Villing-Technologie / Friesenheim and Greiner / Neuenstein for their contribution to the success of the operations.
A spectacular video can be found here: Concreting the first chalice column
Upper picture: Study into supporting the formwork shell for the “Regelkelch”.
The Stuttgart-Ulm railway project, one of the biggest infrastructure projects in Europe at the current time, also includes in its core area the urban traffic and development project known as Stuttgart 21 for transforming the existing terminus railway station into an underground through station.
The new construction of the railway station concourse forms the main building project with the greatest public attention. The building coming into being according to the design of Christoph Architects is characterised by its striking oversized chalice-shaped columns. The construction contractors, Ed. Züblin AG, have entrusted ROBUSTA-GAUKEL with the design and manufacture of the support structure for the formwork units with a view to implementing these chalice columns. The formwork units, themselves, are produced by Züblin Timber.
The extremely complex shape of the chalice columns – their like has never been implemented in concrete up to the present time – does not permit any approach using well-known computational methods. Very elaborate and demanding calculations were necessary for determining the loads occurring. It was also not possible to utilise standard scaffolding systems in view of the given loading and planned construction progress. At the current time, special steel structures for this construction work are being produced at our facilities with support from our partner Villing Technologie in Friesenheim.
We are pleased to be involved in this distinctive city landmark.