## 1 Introduction  
One of the major concerns of using conventional steel, concrete, or wooden piles in bridge structures is their short-term deterioration causing structural failure. In the marine environment, where saltwater accelerates corrosion, traditional materials are prone to corrosion in splash and tidal areas. In the presence of moisture and oxygen, even concrete piles are susceptible to corrosion because of the existence of the steel bars inside the concrete. Several solutions have been presented in the past, such as using epoxy as a coating layer or galvanizing the steel member [1]; however, these approaches had unsatisfying outcomes for increasing the lifespan of steel materials in a corrosive environment [2]. In the long run, excessive use of steel and reinforced concrete materials for pile construction increases the demand for restoration and strengthening [3]. The short lifespan of these conventional materials can increase the cost of maintenance significantly. For instance, either replacing or repairing these piling systems costs more than one billion dollars annually in the U.S. [4]. Maintenance costs in Great Britain are also high, as the allocated budget for repairing bridges is roughly 500 million Euros per year ($592,070,000) [5]. In contrast, fiber reinforced polymer (FRP) is resistant to corrosion compared to steel and other traditional materials. Furthermore, FRP piles can dissipate and absorb the impact energy of ships and other vessels, as well as serve as mooring points. Based on the highly acceptable performance of FRP materials for applications in marine engineering, using FRP materials in construction has gaineda reputation as a practical solution against corrosion, as well as to improve the durability of structural members in a marine environment. Moreover, FRP reinforcement is a more reliable replacement to steel reinforcement, as it enhances the strength of the structure member without adding considerable weight to the structure [6]. Therefore, fiberglass piles are considered as an ideal material for construction in the marine environment. For the design of composite deep foundations in bridge structures, hybrid fiber-reinforced (FRP) materials have greater advantages, compared to non-hybrid materials. For instance, as a hybrid reinforcing method, glass fiber-reinforced polymer (GFRP) sheets have superior features regarding strength, tensile ratio, and stiffness-to-weight ratio. GFRP is both nonmagnetic and nonconductive, which is an advantage compared to traditional materials [7]. Furthermore, the constructability of GFRP is useful for structures which have complex shapes. In addition, these hybrid FRP polymers are more resistant to hazardous environments when exposed to saltwater, or even during destructive hurricanes. Therefore, in specific environmental conditions, such as coastal areas, replacing conventional pile members with GFRP composite piles considerably improves the lifespan of the constructed members against corrosion. Because they enhance the lifespan of the pile, GFRP piles also are deemed as a cost-effective alternative for traditional piles, as they increase the repair cycle of pile bridge foundations. Analyzing the behavior of a strengthened structural member, such as its flexural capacity, deflection response, failure modes, moment redistributions, and ductility, are significant factors for developing accurate design methods and practical structures. Ductility is a critical factor in the construction process; for example, in statically indeterminate structures, it governs moment redistribution within plastic hinges. Redistribution of the moment in structural members ensures the full-capacity usage of the members, which is an essential factor when designing structures that are economical [8]. GFRP is considered a preferred material for enhancing the strength of piles, following methods such as near-surface-mounted and externally-bonded reinforcement techniques [3].