UC Berkeley Geosystems Group Wednesday Lecture Series: Mixed Soil Bottom Seal for Waikiki Tower

Lecture: GeoEngineering: Civil Systems: Civil and Environmental Engineering | February 19 | 12:10-1 p.m. | Davis Hall, 406 Davis Hall

 Doug Schwarm, Atlas Geotechnical

 UC Berkeley Geoengineering Society

Structures in Waikiki, even the largest, lack below-grade parking because groundwater is so shallow. The place name “waikiki” literally refers to artesian water. The neighborhood is as dense as any major urban core, property values are high, and foundation conditions are challenging at best. Hilton Grand Vacations’ new 32-floor Ka Haku Tower is the first project to use ground improvement to facilitate digging deep pile caps through saturated sand.

Atlas Geotechnical designed a conventional bottom seal using primarily 6.5-foot diameter overlapping mixed elements
supplemented by jet grouting at obstructions and along edges.

CFA piles 24-inches in diameter and 110 feet deep will be drilled and grouted through the bottom seal, which is 20 feet thick in places. In addition to sealing out groundwater, the mix design needs to be weak enough to allow drilling.

Initial work revealed several improvements that could be made, including changing to a larger blade diameter, reducing the number of jetted elements, and two changes to the mix design that reduced returns and increased strength. Production mixing is just now underway as abstract is being submitted; the presentation will include data that have not yet been collected.

Doug Schwarm attended Wednesday Seminar here in 1988 before starting a traditional foundation engineering career. He left that to found Atlas Geotechnical 15 years ago so that he could tighten his focus on providing advanced geomechanics solutions to contractors and other direct-user customers. Under Doug’s guidance, Atlas designs various types of ground improvement, designs and troubleshoots shoring and dewatering systems, solves difficult piledriving problems, and troubleshoots the really weird geotechnical problems that affect complex infrastructure.

 CA, pong@berkeley.edu, 5106645249