Prefabrication will help cut the carbon footprint of a major viaduct on the U.K's emerging 140-mile London-Birmingham high-speed railroad HS2 by one-third, eliminating 19,000 metric tons of embedded carbon, according to the turnkey contractor. 

With 68 modular piers sections now rolling off a production line, the Thame Valley viaduct is due to start taking shape later this year. 

To stand just 10 ft above ground level, the 2,890-ft-long viaduct will cross the River Thame flood plane in 36 equal spans, around about 37 miles northwest of London. The river is a tributary of the River Thames.

It is one of 15 viaducts along HS2's $2.7-billion central 50-mile alignment being designed and built by a consortium led jointly by the U.K. and French firms Kier and Eiffage.

The viaduct is "set low into the landscape that benefits from the efficiencies associated with off-site prefabrication," notes Ignacio Chicharro, project director with the consortium. 

To minimize site work, the viaduct deck will be supported by twin prefabricated box girders weighing nearly 100 metric tons each, spanning between piers.

Project owner HS2 Ltd. recently unveiled the facility on the Isle of Grain, Kent, about 90 miles from the site, where the 42-metric-ton pier units are being cast by Spain-based Grupo Pacadar. 

Completed piers for the Thame Valley viaduct at the Pacadar U.K. plant. Photo courtesy of HS2 Ltd.

 

This type of prefabricated design has been "widely implemented by Pacadar on previous high-speed lines," according to the company's U.K. production manager, Fernando Aguilar Pírez. 

The viaduct is "a great example of how our contractors are embracing the latest engineering technique," according to HS2 Ltd.’s head of civil structures, Tomas Garcia.