Builders of the U.K.’s tallest skyscraper, London’s Shard, will save valuable time by excavating its three-floor basement while slipforming the core. A novel machine is now at work, plunging columns ...

...top must be within 1 cm vertically and horizontally. To achieve such tolerances at high production rates, Cartwright took rig design “a big” step from where it’s been for nearly 20 years, he says.