No such thing as impossible: fischer technology’s most extreme areas of application17. January 2020
The water is ice cold with zero visibility. When the research diver Markus Brand places fixings he is usually located up to ten metres below the sea surface. 36 tetrapods (concrete blocks weighing six tonnes) were sank in the North Sea off the coast of Heligoland, for instance. Various high-sensitivity sensors and metal sample receptacles containing mussels are attached to these blocks. They are part of the unique “MarGate” research project by the Alfred Wegener Institute, which aims to discover the effect of climate change on the North Sea and its flora and fauna.
“Underwater installation has become increasingly important in recent years”, Bernd Wetzel reports. He is responsible for providing technical advice to customers by email and telephone for the fixings specialist fischer. “There is particular demand for advice when it comes to fixings under water, below the earth’s surface or at great heights”, Wetzel says. The same applies to anchors that must be able to withstand extreme weather conditions or fixings that are used on historical buildings. “Our customers have often been turned away by several competitors”, Wetzel states. They ultimately end up with fischer, as the following examples of underwater installations (“MarGate” project, North Sea), restorations (Acropolis, Athens), infrastructure projects (“Le Grand Paris”) and tunnel constructions (Brenner Base Tunnel) demonstrate.
Underwater installation – a supreme discipline of construction
The research divers of the Alfred Wegener Institute for Polar and Marine Research in Bremerhaven initially used screws with plastic expansion plugs on the “MarGate” project. “But that didn’t last long”, the research diver Brand explains. The underwater drill holes can only be accessed with a great deal of effort, which is why it is extremely important for the fixing to be reliable and durable – even in rough seas. “We then turned to fischer, and Bernd Wetzel recommended the fischer bolt anchor FBN II to fasten the threaded rods with the sensors to the tetrapods”. The titanium bollards for the barrels containing the mussels were installed with the injection mortar FIS EM and the fischer bolt anchor FAZ II.
Acropolis: A secure hold for sensitive measuring devices
High-sensitivity measuring devices and the bolt anchor FBN II were also used on the Acropolis in Athens. The world-famous historic monument has been afflicted by earthquakes, bombings and sieges in addition to human intervention and the relentless ravages of time. So-called fibre Bragg grating was installed in 2016 in order to monitor the walls’ deformation status and areas that were particularly at risk. These high-sensitivity sensors were installed with the FBN II: “Installation was particularly fast and the bolt geometry enables ideal load distribution”, the fischer Application Engineering specialists explain.
“Le Grand Paris”: Underground expansion of local public transport
The “Le Grand Paris” project is creating added space in Paris, Europe’s most densely populated city. The project is uniting the capital with multiple neighbouring communities. The rail network is indispensable to the city’s transportation: The existing metro and RER network is set to by expanded by approximately 200 kilometres of new routes and the addition of 68 new stops. The existing route 14 has already been expanded by six kilometres and five new stops. fischer’s internal thread anchors FH II-I were used in order to securely fix the console systems of the power supply lines. Multiple pull-out tests were carried out in various building segments in order to find the best product, as the prefabricated parts featured specialist drillings.
Brenner Base Tunnel – maximum safety for rail services
The construction of the Brenner Base Tunnel, the world’s longest underground rail link, is another potential record-breaker. It is due to be completed in 2027. “fischer’s solutions convinced the client because they fit the dimensions and are economic, durable, easy to use and of a high quality. These are decisive features, particularly on demanding construction sites such as the Brenner Base Tunnel”, says Manfred Rabl, fischer Austria’s Technical Advisor in the field who is responsible for the project. The injection mortar FIS SB is being used to install rebars, guide rails, formwork elements and holding fixtures for supply lines. The contractors also used the high-performance fischer ULTRACUT FBS II concrete screws for temporary fixings.
Rottweil elevator test tower: Under constant heavy load
The 264-metre thyssenkrupp elevator test tower in Rottweil is surrounded by unusual facade cladding. Elevator innovations are tested and certified in its twelve shafts. The tower has 17,000 square metres of cladding made of a polymer-coated glass fibre fabric. A steel construction consisting of steel pipes, cables, A-frames and anchor plates connects the facade cladding to the concrete wall. fischer developed specialist solutions for this project that take various wall thicknesses and concrete strength classes into account. “fischer’s service played a crucial role in our being assigned the contract”, said Stephan Gießer, the Project Manager at the time. “We accompanied planners, surveyors and technicians throughout the entire construction process”.