Spanish construction group ACS, via its subsidiary Dragados, will be supplying the world's largest tunnel boring machine for a project aimed at rebuilding a part of State Route 99 damaged by an earthquake in Seattle.

The tunnel boring machine is dubbed "Bertha" and has a diametre of 17.48 metres, equivalent to a six-story building, weighs 7,000 tonnes and is 112 metres long.

It will dig open a tunnel in Seattle to replace the "Alaskan Way Viaduct", which connects the northern and southern parts of Washington State and was seriously damaged by the "Nisqually" earthquake in February 2001.

Bertha was designed by Dragados and manufactured in Japan by Hitachi Zosen. Both entities are part of a consortium group with US company Tutor Perini Corporation.

The machine gets its name from Bertha Knight, Seattle mayor's from 1926-1928, the country's first female mayor in a major city.

Bertha will play a key role in one of the US's largest projects with a budget of more than €1.0bn.

LS

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