Within the last century, coastal structures for infrastructure applications have traditionally been constructed with timber, structural steel, and/or steel-reinforced/prestressed concrete. Given asset owners’ desires for increased service-life; reduced maintenance, repair and rehabilitation; liability; resilience; and sustainability, it has become clear that traditional construction materials cannot reliably meet these challenges without periodic and costly intervention. Fiber-Reinforced Polymer (FRP) composites have been successfully utilized for durable bridge applications for several decades, demonstrating their ability to provide reduced maintenance costs, extend service life, and significantly increase design durability. This paper explores a representative sample of these applications, related specifically to internal reinforcement for concrete structures in both passive (RC) and pre-tensioned (PC) applications, and contrasts them with the time-dependent effect and cost of corrosion in transportation infrastructure. Recent development of authoritative design guidelines within the US and international engineering communities is summarized and a examples of RC/PC verses FRP-RC/PC presented to show the sustainable (economic and environmental) advantage of composite structures in the coastal environment.

This paper discusses the design of a marine dock in Miami, Florida reconstructed after sustaining damage from Hurricane Irma in 2017. This pioneering structure implements accelerated bridge construction methods using prefabricated bridge elements and systems. The structure is made of precast concrete members with basalt fiber-reinforced polymer and glass fiber-reinforced polymer bars, and concrete mixed with seawater. The structure is designed to withstand hurricane loading and the choice of materials is intended to leverage sustainability and resilience.

Marine, coastal structures, and bridges deteriorate prematurely due to corrosion. Numerous failures have occurred in substructure members of these structures, such as piles, leading to very high repair and replacement costs. Problems related to corrosion could be resolved through the use of noncorroding materials such as fiber-reinforced polymer (FRP) bars. This paper presents the design, construction details, driving test procedures, and results of the field dynamic driving testing of precast glass-FRP (GFRP) reinforced concrete (RC) piles, as well as laboratory test results, to determine the piles flexural strength. Four piles were longitudinally and transversally reinforced with GFRP bars, spirals, and ties. Two of the piles were 6.0 m (approximately 20 ft) long, were fabricated, instrumented, and were laboratory tested for flexural strength. The other two piles were 18.0 m (approximately 60 ft) in length, were field installed and dynamically monitored. They were driven and monitored at the Arthur Drive Bridge project site in Lynn Haven, Panama City, Florida. Pile driving and testing were performed with a Vulcan 512 single-acting air hammer. The embedded data collectors (EDCs) were used to monitor the piles during driving operations. Field driving observations and results indicate that no pile damage occurred during installation. GFRP spirals successfully confined the concrete core of the piles and prevented cover spalling during driving. The maximum tensile and compressive stresses measured in the piles were well within the allowable design limits. Design aids and recommendations for good driving practices for GFRP-RC piles were presented. The promising results presented for the driven precast GFRP-RC piles represent a further step toward field application.

Design for slender high-strength concrete (HSC) bridge compression members (columns, piers, and piles) reinforced with glass fiber-reinforced polymer (GFRP) has yet to be addressed in the relevant American and Canadian codes and guidelines. Including such provisions undoubtedly requires a comprehensive assessment of the structural performance of such members, as well as a definition for the slenderness limit below which second-order responses can be discarded. Consequently, full-scale slender GFRP-HSC columns with a concrete compressive strength of 80 MPa and measuring 2,500 mm in height and 305 mm in diameter were prepared and tested at four eccentricity levels (0%, 16%, 33%, and 66% of the column size). The influence of HSC on the behavior of slender GFRP-HSC columns was also assessed with respect to reference normal-strength concrete (NSC) counterparts. Moreover, the effect of two different longitudinal GFRP-reinforcement ratios (3.28% and 4.66%) on the performance of the test specimens was investigated. The test results herein indicate the ability of HSC and GFRP reinforcement to improve column strength and to maintain stability at various loading stages. An analytical second-order model was then developed to extend the research program to include a wide range of parametric studies. The developed model was validated against the test results for 47 FRP-HSC columns selected from the current study and the literature. Lastly, the applicability of the current slenderness limit to HSC columns was verified and a modified slenderness limit was proposed to account for HSC columns with compressive strengths up to 125 MPa.

Potential exists for construction time savings through replacement of cast-in-place substructure columns, piers, or both, with prefabricated bridge elements and systems. Cast-in-place substructure construction requires forming, placing steel, and pouring concrete at the construction site. Using prefabricated elements would decrease the extent of work required at the site and potentially reduce concrete curing time. This research furthers the effort to use ultra-high-performance concrete (UHPC) as a joining material for prefabricated bridge substructure elements. UHPC has a high early strength, requires less development or splice length than conventional concrete, and has been used previously for accelerated construction projects, such as bridge deck replacement with precast units. UHPC also has a discontinuous pore structure that reduces liquid ingress, significantly enhancing durability compared to conventional concrete. Although UHPC has been researched extensively, previous research for reinforcing bar splice and development lengths has focused on #9 and smaller diameter bars. Typically, larger diameter bars are used for substructures. This research determined the required splice lengths for large diameter steel deformed reinforcing bars embedded in UHPC based on 127 individual tests. Three primary variables were included in the testing matrix: bar size, bar spacing, and concrete cover. To achieve at least 75 kips per square inch (ksi) (517 MPa) reinforcing bar stress in UHPC with an early age strength of 14 ksi (97 MPa), the required embedment length ranges from 8 to 13 times the bar diameter and the corresponding splice length varies from 6 to 11 times the bar diameter, depending on the bar size and concrete cover.