5 MG Water Storage Tank Foundation
and Rapid Infiltration Basin (RIB)

5 MG Water Storage Tank Foundation and Rapid Infiltration Basin (RIB)
Geotechnical Investigation

Madrid CPWG completed a geotechnical investigation for a proposed 5MG water tank that was to be 150 ft. in diameter and 37 feet high, along with associated pumps and small structures at the site of an existing water treatment plant in Haines City, Florida. Madrid CPWG also completed a geotechnical investigation for a proposed Rapid Infi ltration Basin (RIB) that was about 1,270 feet long and about 100 feet wide at an off -site location.

The geotechnical report was required to be completed in a very short timeframe.  This project was an important initiative for the City as it would be a major increase in storage capacity.  The seasonal high groundwater was found to be at the existing ground surface at the tank location.

Madrid CPWG Approach

Madrid CPWG coordinated with the City and Client with multiple meetings, including one at the site, in order to complete the fieldwork and final report within the required schedule and to ensure a good understanding of the project requirements and conditions.  Managing the project required a well-defined schedule and strict adherence to cut-off dates in order to meet the deadline for the report.  Internal coordination between drilling, lab, report writing, and report reviewers ensured minimal slack time was allowed and the project remained on schedule.  Madrid CPWG’s internal goal was to complete the report early, so if any unforeseen obstacles appeared, the report would still go out on time.

Soil borings were completed to sufficient depths to ensure that settlement estimates would accurately account for any soft and/or other potentially problematic deep subsurface conditions.  We also recommended the addition of 3 feet of clean sand fill at the tank and 2 feet at other structures to improve bearing capacity safety factors.

At the RIB site, Madrid CPWG coordinated with the City and Client with multiple meetings and Madrid CPWG recommended use of Ground Penetrating Radar (GPR) to survey the entire site to help characterize subsurface features, such as confining layers, and to help with selection of soil boring locations. We completed four Standard Penetration Test (SPT) borings across the site, with one boring being extended to a depth of 150 feet to attempt to find limestone bedrock. A piezometer was also installed to verify water table depth, which was at 37
feet. All work except for GPR survey was in-house.

Madrid CPWG Benefit

The City received the design in time to submit necessary forms to regulatory agencies without having to delay the project for another period of time.  The increase in elevation of the tank floor will ensure groundwater will not affect foundation performance and will help ensure both longevity of the structure and foundation stability. Madrid CPWG used multiple types of testing that revealed important details about subsurface conditions that may not have been discovered without those specific tests.  The tests included:

• Deep SPT borings
• GPR surveys (completed by Madrid CPWG’s subcontractor, GeoView, Inc.),
• Piezometer readings