London's new railway, the Elizabeth line, constructed as part of the Crossrail project, was officially opened in May 2022. One of Europe’s biggest rail infrastructure projects of recent decades, work began on the creation of this new, 118-km-long rail link crossing London from east to west in May 2009. 42 km of new rail tunnels and ten new stations were built for the Elizabeth line. ArcelorMittal steel fibres were used to reinforce the concrete of the tunnel walls.

New tunnels and underground stations

Eight giant tunnel boring machines (TBMs) carved out the 21 km of twin-bore tunnels below the busy streets of London, operating in 24-hour shifts seven days a week. Each was 150 m in length and weighed around 1000 tonnes. The TBMs were not just tunnelling. They were removing the muck and creating a sealed concrete tunnel as they went. They have an external diameter of 7.1 m which allowed for an inside tunnel diameter of 6.2 m once the concrete tunnel segments were put in place.

The concrete sprayed by the TBMs to seal the tunnel walls is reinforced with steel fibres - as are the pre-cast concrete segments that form the inner shell of the walls.

Steel fibres by ArcelorMittal: innovating for Crossrail

ArcelorMittal was chosen as the main supplier of steel fibres for this project, with more than 11 000 tonnes of steel fibres being produced at ArcelorMittal WireSolutions’ plants in Sheffield, UK and Bissen, Luxembourg.

In the Elizabeth line’s eastern tunnels, from Limmo Peninsula to Farringdon and from Pudding Mill Lane to Stepney Green, around 4000 tonnes of ArcelorMittal HE++ 90/60 steel fibres were used to reinforce the segments and more than 1000 tonnes of HE+ 55/35 fibres were used in the sprayed concrete.

For the new Thames tunnel from Plumstead to North Woolwich, 1000 tonnes of HE++90/60 was supplied for the segments.

Apart from the tunnels, ArcelorMittal steel fibres were also used in the construction of the new stations at Liverpool Street and Whitechapel.

The ArcelorMittal WireSolutions sales, technical support, R&D, and production teams worked together to supply the steel, but also assisted the material engineers and production managers of the joint ventures involved in the projects.

WireSolutions developed two new grades of high-performance steel fibres with exceptional tensile strength specifically for the requirements of Crossrail: HE++ 90/60 for the tunnel wall lining segments and HE+ 55/35 for the sprayed concrete.

Steel fibres used in concrete not only provide reinforcement, but also reduce and control concrete shrinkage. Furthermore, they prevent micro-cracks in the concrete from converting into major cracks.

Text:
Constructalia

Images:
© Crossrail Ltd
© TfL

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Crossrail

In the north of Portugal, almost halfway between Porto and the Spanish town Ourense, the Tâmega River hydropower complex is being developed on the Tâmega River by Spanish power company Iberdrola Generación. Three dams and three hydroelectric plants are being constructed and are one of the largest constructions of this type in Europe in the last 25 years with a total investment cost of €1.5 billion.

Yearly energy output equivalent to the consumption of 440 000 Portuguese households

The Tâmega River hydroelectric complex will be comprised of three dams (named Gouvães, Daivões, and Alto Tâmega) and will have a combined power of 1158 megawatts (MW). Once fully operational, Iberdrola estimate a total of 1766 gigawatt hours (GWh) of electricity will be produced each year - the equivalent of the consumption of 440 000 Portuguese households. This supply of clean energy will omit approximately 1.2m tonnes of CO2 emissions into the atmosphere and reduce consumption of oil by 160 000 tonnes.

ArcelorMittal steel fibres reinforced shotcrete used for underground galleries

Over 500 t of ArcelorMittal high performance steel fibres have been supplied for this project. ArcelorMittal's HE55/35 and FE60/36 fibres have been used to reinforce the underground galleries via shotcrete methods and to construct a robust encasement to protect and cover the steel pipes used to transfer the water.

The construction of the three new dams and hydroelectric plants is developing at a good pace and in line with the timetable set out at the beginning of the project. With two thirds of the work already completed, the complex should be fully complete in 2023 - nine years after initial construction began.

Text:
ArcelorMittal Bars & Rods

Image:
ArcelorMittal Bars & Rods

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