Project Spotlights

Landslide in Maryland

Debris from an old slope failure caused water in the creek to change course and erode the toe out of the bank. The slope above the creek failed at two locations and damaged sidewalks, fences and lamp poles. The slides continued to move and threatened buildings, gas lines, water lines, power lines and communication lines.

PCC designed and monitored installation of a cantilever steel pile retaining wall with tiebacks and precast concrete facing.

The wall has been installed and the structures above the wall stabilized and repaired.

The next phase of the project, stream restoration, will include gabions and rip-rap to prevent further erosion of the sides of the creek below the concrete facing.

Bethesda Triangle

This 12-story apartment building has four levels of underground parking extending 40 feet below the street. The small brick building was underpinned to a depth of 45± feet using hand-dug concrete pits.  Dispersive wave testing performed on the drilled piers supporting the taller building indicated that it did not have to be underpinned. The excavation was shored with steel soldier piles, tiebacks and temporary wood lagging. The perimeter walls were constructed as one-faced reinforced concrete walls. Columns supporting two million pounds are supported on footings designed for 15,000 psf on disintegrated rock.