SYMPOSIA PAPER Published: 29 July 2019
STP161120170166

Case Studies: Driving Concrete Piles in Florida Pinnacle Limestone

Source

In 2012, while the Florida Department of Transportation was widening Interstate 75 from Fowler Avenue to Bruce B. Downs Boulevard north of Tampa, dynamic load testing was performed on the test piles using two different systems: Pile Driving Analyzer (PDA) and Embedded Data Collector (EDC). The dynamic load tests indicated that the piles had encountered pinnacle limestone conditions, which was not anticipated based on the soil borings. Pinnacles are columns or cones of carbonate rocks left by the dissolution of the surrounding rock. Pinnacles with soft or loose overburden immediately above them can pose tremendous challenges to geotechnical engineers. Despite having very small measured stresses and predicted stresses in both the PDA and EDC systems (maximum top compression stress, toe compression stress, and tension stress all ranged from 0 % to 50 % of the allowed driving stress limits), the first test pile experienced significant damage (PDA BTA = 69 %) and was extracted. Subsequent test piles were driven with more caution as well as with thicker pile cushions; the measured as well as predicted stresses were even smaller for the piles. Still, some test piles experienced minor damage, and driving was stopped when both the PDA and EDC indicated a BTA of approximately 90 %. One of the latter test piles encountered minimal resistance and did not reach the required bearing capacity and was subsequently extracted and showed visible minor damage. This article summarizes the experiences and recommendations regarding driven piles in a pinnacle limestone formation.

Author Information

Nguyen, Thai
H2R Corp, Pinellas Park, FL, US
Hart, Dan
H2R Corp, Pinellas Park, FL, US
Rancman, Dave
H2R Corp, Pinellas Park, FL, US
Price: $25.00
Contact Sales
Related
Reprints and Permissions
Reprints and copyright permissions can be requested through the
Copyright Clearance Center
Details
Developed by Committee: D18
Pages: 651–663
DOI: 10.1520/STP161120170166
ISBN-EB: 978-0-8031-7668-3
ISBN-13: 978-0-8031-7667-6