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Is Engineering Boring? How Big is Bertha?

April 19th, 2013

A career in engineering doesn’t necessarily mean being tethered to an office and a desktop computer running a version of AutoCAD. In many cases, engineering entails a day spent out in the real world getting dirty. And in the case of “big” Bertha, it means getting real dirty!

Introducing Bertha: The World’s Biggest Single-Bore Drill

An example of something boring that is also quite exciting; Bertha is the world’s biggest single-bore drill. Made up of 41 separate pieces, with a cutter head that weighs 886 tons, Bertha sports a width of nearly 60 feet. This massive drill is currently being used in a two billion dollar project to build a tunnel for Highway 99 underneath downtown Seattle– from Sodo to South Lake Union.

When the Highway 99 tunnel project is completed in 2016, it will permit the demolition of the Alaskan Way Viaduct. With that eyesore removed from the Seattle waterfront, the opportunity exists for new parkland development. But first they actually have to get Bertha tunneling underneath the Emerald City!

Starting Bertha on her Underground Journey

Just getting Bertha in place is a large engineering project in itself. Transported to Seattle from Japan, Bertha arrived, un-assembled, in late March. The drill’s parts are shuttled one by one at walking speed from the dock to a 100-foot pit where the final assembly is completed. Fully put together, Bertha weighs 6,800 tons — the same as 38 jumbo jets!

A figurative ton of concrete will surround the drill, keeping it aimed squarely at its final destination in South Lake Union. The concrete helps keep groundwater from flooding the drill, causing realignment. Additionally, beams under the Alaskan Way Viaduct are wrapped in carbon fiber to prevent tunneling vibrations from damaging the viaduct while it is still in use.

A conveyer belt system is being used to move soil from the tunnel project back to the dock area, where barges will ship it to a quarry. All told, this is a multi-faceted modern engineering operation.

Interested in working on exciting projects that involve something like Bertha? Contact the recruiters at The Talley Group, as one of the Northwest’s leading engineering staffing firms, they can help make sure your engineering career is never boring.

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