Area

40,000 sq.ft.

Cost

$5 Million

A 50 foot high retaining wall was designed to replace an existing wall laterally supported by a garage structure. The new wall is an exceptionally heavily loaded concrete retaining wall holding back a steeply-sloped hillside. Residential homes are perched on top of the slope, which extends another 40 to 50 feet above the top of the wall. The wall varies from 20" to 12" in thickness in several segments and is tied back at 2 levels with high strength (270 ksi) grouted tendons.

The garage was badly cracked and failed as a result lateral movement of the former wall. After temporary tiebacks were installed and the garage removed, access to strengthen the wall was possible. A new reinforced concrete layer was poured against it and additional tiebacks added. The wall was designed for hydrostatic, gravity and seismic loads to meet NYC and other code requirements.