Dynamic Pile Testing for Florida’s High-Speed Rail Foundations

The All Aboard Florida Passenger Rail was a private high-speed rail project connecting Orlando in Central Florida to Miami in South Florida across 235 miles. The rail system was designed to operate at speeds of up to 125 mph, reducing travel time between the two cities to approximately three hours.

One of the key challenges of the project was coordinating with the various entities involved, including Brightline, CFX, the Florida Department of Transportation, and the Florida Turnpike. Understanding and meeting project specifications was essential to maintaining deadlines and supporting successful project completion.

GRL Engineers provided dynamic pile testing and related services for various structures along the 35-mile section between Cocoa and Orlando International Airport.

Dynamic Pile Testing and Analysis

GRL Engineers performed testing services for multiple bridge structures on the western portion of the rail corridor, including the Goldenrod Road Underpass, SR 528 at Narcoossee Road, and SR 417. Services were also provided for structures on the eastern portion of the rail line, including Pine Street, I-95, the SR 528 Flyunder, Industry Road, and the SR 528 Underpass.

To improve efficiency, GRL Engineers conducted GRLWEAP analyses for the various pile and hammer combinations used throughout the project. These analyses provided recommendations for hammer selection, cushion and helmet requirements based on pile type, pile length, required ultimate capacity, and geotechnical information.

During pile installation, GRL Engineers monitored pile driving using the Pile Driving Analyzer® (PDA) and utilized CAPWAP® software to determine the ultimate bearing capacity of selected piles. Some locations used test piles and established driving criteria for production piles, while other locations implemented 100 percent dynamic pile testing.

The foundation work included large, long prestressed concrete square piles, some of which required splicing, as well as long steel pipe piles used to support temporary construction trestles.

Project Results

Each bridge location along the rail corridor required evaluation of site-specific pile types and geotechnical conditions.

Some foundation elements consisted of 24-inch and 30-inch square prestressed concrete piles founded in deep sand bearing strata. At certain locations, pile lengths reached up to 167 feet. These long piles were installed in shorter sections and connected using mechanical splices.

GRL played an important role in monitoring pile installation to ensure that driving stresses remained within allowable limits specified for these pile types. Dynamic pile testing results from one of the prestressed concrete piles are presented in Figure 1, while the corresponding CAPWAP analysis is shown in Figure 2.