A well-known tech company is building a new campus for their expanding workforce just outside of San Jose. Our Ground Improvement Division was contacted to provide a design/build solution to improve the ground beneath all three office buildings and a multi-story garage. Malcolm proposed an economical stone column solution that allowed an early design and permitting phase. When completed, over 7,800 Stone Columns with an average depth of 18′ were installed with variations in spacing and depth depending on column loads. The stone columns were installed into highly layered sands, silts, and clays, which varied widely across the site. Predrilling was required to advance through the upper stiff clays. Our work plan incorporated three bottom feed, crane mounted vibro-floats, paired with two predrilling units to accommodate schedule acceleration. Quality assurance and acceptance was provided by 20 post-treatment cone penetration tests (CPTs), along with liquefaction analysis, and a total of 8 load tests. Malcolm’s schedule acceleration included extended work shifts and constant equipment maintenance. The work was completed in only 8 weeks – well ahead of the schedule and on budget.
