Project

Two 10-story hospital towers connected by a two and three-story podium structure, with a detached central utility plant

The Problem

The geotechnical investigation revealed layers of loose sands and soft clays above the hard limestone.  The loose and soft soils would cause excessive settlement of all structures if conventional shallow foundations were used.

Earth Tech Solution

The geotechnical engineer recommended the two towers be supported on a deep pile foundation and the podium and central utility plant be supported on shallow foundations with soils improved by Vibro Replacement. Earth Tech partnered with Precast Piling Technology to install approximately 1,000 steel pipe piles and 600 Vibro Replacement stone columns. Pile capacities were 125-tons in compression, 30-tons in tension and 14.5-tons lateral. Stone columns allowed for shallow foundations to be designed using a soil bearing pressure of 6,000 psf.  Pile capacities were verified using high-strain dynamic load testing via the PDA system and the Vibro Replacement program was verified using a full-scale plate load test.