Geotechnology will be attending and presenting at the 2009 Deep Foundations Institute (DFI) 34th Annual Conference on Deep Foundations from October 20-23, 2009 at the Westin Crown Center in Kansas City, Missouri. Sheryl Gallagher, P.E., senior geotechnical engineer in our Kansas City office, will be presenting the I-470 Mine Remediation project at 9:00 a.m. on Friday, October 23, 2009. Frank Callanan, P.E., vice president development market team will be presenting 25 Story Structure on River Flood Plain Soils Improved by Vibrocompaction and Compaction Grouting in conjunction with Jeffrey Hill, P.E. of Hayward Baker at 4:55 p.m. on Wednesday, October 1, 2009.
25 Story Structure on River Flood Plain Soils Improved by Vibrocompaction and Compaction Grouting by Frank Callanan, P.E., vice president
The Ameristar Casino St. Charles expansion includes a 26-story hotel and a nine-level parking garage. The expansion site is located in the Missouri River floodplain. Ameristar Casino asked Geotechnology to provide geotechnical design recommendations for the hotel and parking garage. Project constraints included adjacent wetlands protection, construction adjacent to the existing casino facility, flood protection, riverbank stability and liquefaction mitigation design. A seismic site-specific ground response analysis was required to develop seismic design spectral response accelerations. Potential post-liquefaction settlement was calculated to be up to 14 inches.
The team evaluated alternative foundation options and construction methods to overcome the many site challenges. Options to achieve goals included structurally supporting the expansion on deep foundations or to implement ground improvement techniques to overcome the potential post-liquefaction hazard. The team concluded that ground improvement was the optimum course of action.
Ground improvement included removing the cohesive soils from the site, densifying the underlying sand to depths of 35 to 50 feet using vibrocompaction and compaction grouting techniques as well as underpinning existing foundations with micro-piles. The improved ground allowed the team to support the high-rise hotel on a mat foundation and the parking garage on shallow foundations. The design solution is unique to St. Louis, provided the client with $2.5 million cost savings over deep foundations alternatives and enabled construction to stay on schedule.