High Rise

Projects: Geotechnical Exploration, Foundation Design, Construction Inspections

Geotechnical Engineering



No sooner had a real estate developer begun erecting a new 35-story high-rise residential tower than he got the bad news: deep foundation costs would exceed estimates by over $1 million dollars and postpone completion by two months. The problem surfaced at the start of construction, when full-scale load tests revealed that available friction would prove insufficient to drill the deep foundations. ATC was contacted and asked to review this geotechnical conclusion and provide alternatives.



ATC reevaluated the entire foundation system and concluded that the design shaft lengths could be reduced, without compromising safety, to save $300,000. Construction time was not lost; in fact, the schedule was reduced by approximately four weeks. Noting that subsurface data was limited, ATC initiated a rapidly executed program of additional soil borings and rock coring to further describe subsurface stratigraphy and obtain additional data for detailed foundation analyses. A three-week program of soil boring and reevaluation prevented delays, as initial foundation elements were installed concurrently.