Buildings



View of FAIR from the east, showing the existing GSI facility (1) in the background and the underground particle accelerator ring (2) and other FAIR buildings (3) in the foreground.

FAIR is a major construction project that includes a 1.1-kilometre tunnel and 23 different buildings. The logistics required for an undertaking of this magnitude are fascinating. It involves organising large numbers of people who have to work together over a relatively small area. It also entails coordinating huge deliveries of material to very tight schedules. Additional challenges include the ground conditions, the actual geometry of the facility and its function as a high-tech research enterprise.

 

The access road



The easterly section of Messeler-Park-Strasse has been improved and widened to make it part of the access road. (Photo: Gaby Otto for FAIR)

The access road leading to FAIR is used by trucks and other construction vehicles. Since January 2013 the traffic light system for the outer construction road is in operation. The off-site section of the road branches off from the B3 main road and runs past the Darmstadt-Wixhausen industrial estate to join Messeler-Park-Strasse. This route takes construction site traffic away from residential areas (map). Part of Messeler-Park-Strasse and the bicycle lane have been widened to ensure that the road will never be completely blocked even if two trucks break down side by side.

Traffic enters the site from the off-site access road to the south, and exits on the northern stretch of the off-site access road (Prinzenschneise and Messeler-Park-Strasse).

44 trucks an hour during peak traffic

During its busiest hours, 44 trucks will be using the off-site access road each hour to enter and leave the site. By comparison, the 2010 traffic census found that around 17,020 vehicles passed the sign for Darmstadt-Wixhausen on the B3 main road per day, i.e. 709 vehicles each hour (see traffic volume maps published by the regional government of Hesse, in German).
In addition to the off-site access road, the site itself is crisscrossed by a network of additional roads. These on-site access roads are used for a range of purposes, for example, transporting material excavated from trenches to the designated stockpiling areas near the site.

Noise and dust levels are regularly measured at different points on the access road in order to control emissions.

Tyre washing facility



Tyre washing of a lorry
The FAIR construction site is equipped with a tyre washing facility. (Photo: Gaby Otto for FAIR)

A tyre washing facility is installed at the northern exit from the site to prevent trucks and construction vehicles from soiling public roads.

Alternative routes for pedestrians, cyclists and equestrians



Map of FAIR and the surrounding area showing diversions (Map: Markus Bernards for FAIR)

The construction site means that pedestrians, cyclists and equestrians can no longer use Prinzenschneise (north of GSI), Dreischläger Weg or Neuwiesenweg (both east of GSI). Pedestrians and cyclists can bypass the site by following the tiny dotted route to the south or north, equestrians may follow the route marked with thick dots (see map). FAIR has paid for the Tannackerschneise forest path to be reconditioned. During longer rainy periods, the northern alternative route is not recommended for cyclists, as the „Mörsbacher Grund“ rural path is not paved due to nature conservation laws. Therefore, cyclists should choose the southern alternative route when the weather is bad.

Concrete mixing plant



Concrete wall
(Photo: Markus Bernards)

600,000 cubic metres of concrete will be required to build FAIR. It therefore makes sense for the site to have its own concrete mixing plant. Mixing concrete on site means less transport. It is also a more efficient, simple way of synchronizing supply and demand. In addition, an on-site mixing plant will ensure that all concrete is of a uniform quality standard.

Excavation



Stockpiles
Temporary topsoil stockpiles south-easterly of the site. (Photo: Markus Bernards for FAIR)

Two million cubic metres of soil will be moved during the construction of FAIR – the same volume that would be shifted to build 5,000 private homes. To keep transport distances to a minimum, the excavated material will stored at the edge of the construction site, saving money and reducing emissions. Before the first bucket-load of soil is removed, however, the construction logistics team will have optimised all processes to get the most out of the available storage space. This includes planning the exact location for storing material from individual trenches as well as planning the precise point at which it has to be excavated and stored. The logistics team also identifies material that can be immediately reused. Topsoil is particularly important and therefore stored separately. It is carefully managed so that the majority can be used to landscape FAIR when construction work is complete.

Managing ground water



Graphics how ground water is managed
Injection wells will be used to feed groundwater back into the ground in the immediate vicinity of the construction site. (Graphics: Carola Pomplun/Markus Bernards for FAIR)

Great care is being taken to ensure that the FAIR construction site will not impact the neighbouring wooded area, groundwater wells or GSI buildings. Intelligent groundwater management is crucial here. The pumps used to drain the construction pit will lower the groundwater level, creating a groundwater funnel. To ensure that this remains as localised as possible, we will be using around 50 injection wells to feed this water back into groundwater supplies. This will largely restrict the groundwater funnel to the construction area and prevent construction activity from having a significant impact on trees and groundwater wells in the vicinity.

The 1.1-kilometre tunnel ring will be completed in gradual, open-pit steps. Each stage will measure around 200 metres. This means that groundwater will only be lowered in the section currently under construction.

Prior to the start of construction, external assessors calculated the size of the groundwater funnel as part of the approval process required by German water law. Furthermore, groundwater levels will be continually measured at numerous locations around the site during construction. This will ensure that changes in groundwater levels under habitats and woodland sensitive to hydrological fluctuations remain within the natural bandwidth.

Active groundwater management also enables us to minimise any potential impact of water movements on the scientific work carried out at GSI. The particle beam equipment used at FAIR is extremely sensitive and can be affected by even very slight structural movements.

  

Wastewater Disposal Line for FAIR



Enlarge picture
Wastewater Disposal Line (Photo: Markus Bernards for FAIR)

South of FAIR and GSI the first part of the FAIR wastewater disposal line has been built. The wastewater disposal line will be situated under the construction road and will lead around the GSI wastewater treatment plant. The wastewater disposal line will be connected to the local wastewater system of Wixhausen later on.

Surveying



Measurement station in Mörsbacher Grund ...
... and surveyor taking measurements on the edge of the construction site (Photos: Markus Bernards for FAIR)

Surveyors have set up numerous measurement stations around FAIR, defining key coordinates in a virtual network of measurement lines that spans the construction site. The surveyors use this network of lines to transfer the building blueprints to the construction site. It enables them to pinpoint the exact location of buildings and the routes of roads. The surveyors can also predict how much buildings will settle after construction.

The measurements stations are encapsulated by concrete rings to prevent them being accidently rammed by construction or forestry vehicles.

Piles



Giant drill machines are brought into position.
The concrete for the piles is being prepared on site in a small concrete mixing plant.
In a workshop hall, for example, welding work is performed.
The work for the piles is managed in these containers. (Photos: Markus Bernards for FAIR)

Exactly 1,339 piles will stabilise the subsoil and minimise building settlement. Above all, they should ensure that FAIR’s buildings settle evenly. To do this, engineers dug holes up to 68 metres deep and 1.2 metres wide. These were filled with steel-reinforced concrete. This process was tested in summer 2011 on the grounds of GSI.

The buildings' foundations will sit directly on the piles, which is called a combined pile raft foundation.

The first pile was built in March 2013 (see Youtube-Video), the work was completed in May 2014.

Accelerator tunnel



Graphic of cross-section of the large tunnel
Cross-section of the large tunnel ring, where the centre of the ring is on the right. (Graphic: Markus Bernards for FAIR)

The accelerator tunnel has a circumference of 1.1 kilometres. Inside, there is enough space for two circular accelerators (the heavy ion synchrotron SIS 100 and SIS 300) placed on top of each other. A supply tunnel will be built next to the accelerator tunnel. This will contain, for instance, powerlines and supply pipelines for the liquid helium used to cool the magnets to minus 269 degrees Celsius. At this temperature, electricity flows through the magnets without any resistance, making them superconductive. This enables them to generate extremely strong magnetic fields. There is also room in the supply tunnel for power supply units that can, for example, convert alternating current into direct current or check the quality of ion beams.

The tunnel ring isn’t actually circular - it’s hexagonal. It needs to be this shape because the ion beam can only be focussed in the straight sections of a tunnel. And the beam needs to be repeatedly focussed as the electrically charged ions repel each other. The straight sections are also where the quality of the ion beam is controlled and the particles accelerated.

The accelerator tunnel will be constructed in open building pits. Digging a tunnel directly underground would not be economically viable for a number of reasons. The radius of the hexagon’s curves, for example, would be too narrow in places for tunnelling equipment. The tunnel will be built in sections of around 200 metres. At its deepest point, the floor of the tunnel will be approximately 17 metres below the surface. The machines and technical equipment will only be installed in the tunnel (via two supply shafts) once construction is complete.

Transfer building and main supply building (north)



The transfer building is located under the long main supply building (north). It serves as a junction where numerous beams cross paths (3D model).
The entire facility (by comparison) (ion42 for FAIR)

The most complex building in the facility  the transfer building  will also be one of the first structures to be built. It will be located underground, to the south of the accelerator ring, where it will serve as a kind of “signal box” for the ion beams, setting the “tracks” that guide the beams in and out of the circular accelerator. There are also beam paths that lead directly from the GSI pre-accelerator to the experiment stations. The transfer building will extend 17 metres below street level.

The main supply building (north) will be built over the transfer building. It will rise to a height of 20 metres above street level and will be approximately 172 metres long. The main supply building will house the power supply systems for the magnets in the accelerator as well as the water supply for certain cooling systems. The accompanying heat exchangers will be installed on part of the roof.
Both buildings together will offer around 6,000 square metres of usable space.

 
(c) 2017 FAIR
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