Behavior of fiber reinforced polymer piles with octagonal cross-sections in integral abutment bridge foundations

Abstract

Billions of dollars worth of losses are incurred due to corrosion and degradation of bridges in the United States. In a conventional bridge, deicing salts and chemicals cause rapid degradation in expansion joints, stiffeners, and other structural components. One of the solutions to tackle such a problem is to eliminate expansion joints in the system and design the whole bridge as an integral abutment bridge. In this type of bridge, the abutment and the deck act as a monolithic system. An integral abutment bridge has no expansion joints. Movement due to thermal expansion and contraction is accommodated by the abutments, which in turn transfer the movement to the piles. The maintenance costs of integral abutment bridges are considerably lower than the traditional jointed bridges; therefore, most state highway departments in the United States recommend the use of integral abutment bridges whenever possible. Using alternatives to conventional piling materials is another solution discussed in this thesis and will be the main focus of the same. Fiber Reinforced Polymer (FRP) piles have some advantages in corrosion resistance and hence can be economical in aggressive environments. In this thesis, FRP piles with octagonal cross-sections were analyzed for their behavior in integral abutment bridges. The octagonal section can easily be manufactured using a vast array of manufacturing methods, especially by the filament winding method, which is a cheaper manufacturing option as compared to other methods like pultrusion. Octagonal sections provide flat surfaces that make operations like bolting easy. In addition to this, irregular octagonal sections can provide stiffness and flexibility about two perpendicular axes simultaneously. Three-dimensional models were made and analyzed using ANSYS Workbench with the help of ANSYS Composite PrePost (ACP) modules. Over 300 soil-pile models were analyzed in this study. The results in this thesis depict the trends captured by varying different parameters for various soil-pile models.