St. Francis Barrack Survey
Environmental, Utility, Topographic, Boundary
St. Augustine, Florida
Army Corps of Engineers
October 2020 through December 2020
Degrove was tasked with completing a Boundary, Topographic, Utility, Ground Penetrating Radar, and Electrical Resistivity Imaging Survey, of the St. Francis Barracks. The main purpose of this survey was to identify any anomalies or suspected voids caused by salt water intrusion or improper drainage.
Main Project Tasks
Degrove was tasked with completing a Boundary, Topographic, Utility, Ground Penetrating Radar, and Electrical Resistivity Imaging Survey, of the St. Francis Barracks to identify potential voids and anomalies that may pose a threat to the stability of the seawall and other structures on the property.
The GPR survey was completed utilizing a GSSI 350HS GPR antenna and an SIR 4000 GPR Controller. Data was collected from the seawall, west 50 feet. The eastern 15 feet of the survey area was collected on a 1.5 foot grid and the western 35 feet of the survey area was collected on a 5 foot grid. The collected data was processed and analyzed in the GSSI Radan 7 software, for the detection of any anomalies and potential voids.
The ERI survey was completed utilizing a 56 electrode SuperSting Imaging System. Data was collected from the seawall, west 25 feet, with lines run North to South. RTK GPS was utilized to layout the spacing of the probes. The data was processed and analyzed in EarthImager 2D and EarthImager 3D. During processing several iterations were run on each line to remove any noisy data. Cross section images of each line were exported. The files for both the northern and southern areas were combined into 3D images, plan view slice images were exported at one foot intervals down to a depth of 10 feet. Areas of interest that were noted in the GPR and ERI surveys were probed to a depth of 5’, to assist with interpretation of the data. The Topographic, ERI, GPR, and probe data was examined for evidence of voids, debris, and changes in soil type.