Projects

Bullfinch Crossing Residential Tower

Boston, MA

This project showcased Hub’s complete spectrum of deep foundation capabilities with installation of slurry walls, drilled shafts, micropiles and two types of earth retention.

It was our first slurry wall project, at a particularly challenging and restricted site in downtown Boston at the intersection of Congress Street and New Sudbury Street. A 90-by-160 foot notch was demolished from the hulking Brutalist garage that sits on the site—an extremely small site for the extensive foundations we installed and the sheer number of big rigs involved. Each day was like a game of Tetris.

The contract called for a muti-faceted foundation supporting a 42-story tower consisting of an earth retaining system of drilled-in-place soldier beams along New Sudbury Street and a micropile earth retaining system adjacent to 115KV buried power lines. Due to access constraints, the design specified 100 micropiles along the back edge of the site. The core of the building is supported by heavily reinforced slurry walls; the column loads are supported by LBEs, one of which had a 17-by-730-pound beam with two-inch cheek plates embedded in the concrete.

Our Liebherr 895 220-ton capacity crane handled rebar cages and site support. We placed three caissons where existing utilities prevented access with the rectangular LBEs. We installed the core slurry walls and LBEs with a Leffer Clamshell and the Bauer Cutter BC35. The Bauer MAT Plant, or desander, cleaned the slurry. Our Derrick Centrifuge facilitated the final processing of the slurry. We installed six more drilled shafts to support a tower crane foundation. In addition to our drilling rigs, we maneuvered four cranes, a concrete pump truck, and an excavator to carry out the project.

• Liebherr 855 90 ton crawler crane equipped with 80′ of boom. Excavation rig with Leffer clamshell.
• Liebherr 895 220 ton crawler service crane equipped with 140′ of boom.
• Bauer MC-96 130 ton crawler crane equipped with 100′ of boom with Bauer BC-35 trench cutter.
• Mantis 14010 70 ton crawler crane equipped with a telescoping boom that extends over 100.’
• Bauer MAT plant BE-550 desander with associated pumps and Derrick centrifuge.
• Soilmec 825 drill rig
• Casagrande C-8 drill rig
• Magni Rotating Telehandler RTH5.265