Eustis Engineering L.L.C. performed geotechnical services during design and construction for a new Reactor Project for Marathon Petroleum Company LP (Marathon) existing facility in Garyville, Louisiana.  The project comprised transporting two new reactors across the Mississippi River Levee.  The levee crossing utilized earthen ramps on the flood and protected sides of the levee with a temporary bridge spanning river road.

Eustis Engineering initially performed preliminary analyses assessing the Mississippi River crossing in May 2021 using available subsurface data from geotechnical explorations completed by Eustis Engineering between 1973 and 2020.   An additional exploration was performed in June 2022 to better understand the soil properties at the site as these were the heaviest vessels transported to the facility to date.   These data were utilized by our design team to evaluate both local and deep-seated global stability of the levee crossing for support of a levee crossing permit from the governing agencies.  Due to the weight of the vessels, a pile-supported landing bridge was required to satisfy slope stability requirements.  Eustis Engineering provided recommendations for the landing bridge piles and a temporary sheetpile retaining structure that was needed to construct the landing bridge pile caps.

In August 2022, Eustis Engineering performed an additional exploration to provide recommendations for the reactors’ permanent foundations as well as recommendations for transporting, temporarily storing, and lifting the reactors to their final destinations within the facility. Data from previous explorations and test pile programs, performed by Eustis Engineering in the vicinity of the project site, were utilized to supplement the new data for these evaluations.

In March 2023, Eustis Engineering observed the heavy haul road proof load test performed using a self-propelled modular transporter (SPMT) and provided recommendations to address locations where rutting and other minor localized deficiencies were observed.  The SPMT was loaded to exert a ground bearing pressure equivalent to the pressure expected during transport of the reactors.  Eustis Engineering also performed an additional exploration to evaluate an alternate haul route path and an alternate crane configuration for the heavy lift.

Eustis Engineering also provided construction phase services for this project.  Prior to the installation of piles for the landing bridge and reactor foundations, we evaluated the proposed driving systems using Wave Equation Analyses of Pile Driving (WEAP) methods to provide installation criteria for the piles foundations.  We also performed dynamic pile testing (DPT) with signal matching verification (CAPWAP analyses) to evaluate driving stresses, pile integrity, and ultimate capacity at the time of testing.  The DPTs were performed by our field engineer during the installation of the piles and during restrikes.  The restrike DPTs were performed after set times of 2 hours to 22 days to develop set curves to predict when the job piles would achieve the required capacity.  Eustis Engineering logged and reviewed the installations of the job piles to verify the design requirements were met.

In October and November 2024, the new Reactors were successfully offloaded from barges staged in the Mississippi River and transported to their temporary storage areas.  The offloading bridge and temporary bridge spanning river road performed as designed, and transportation of the reactors through the facility was performed with no complications.  The final phase of lifting the reactors onto their permanent foundations will be performed in the Spring of 2025.