Close Look at Construction Issues and Performance of Four Fiber-Reinforced Polymer Composite Bridge Decks

Four different fiber-reinforced polymer (FRP) panel systems were installed in a 207 m, five-span, three-lane bridge in an effort to assess the constructability, performance, and applicability of bridges with fiber-reinforced polymer composite decks. This paper examines whether four common deck systems are able to realize many of the anticipated benefits of using FRP composites in lieu of conventional reinforced concrete bridge decks. Particular installation issues, connection details, and specific construction techniques for each deck system are described, along with a discussion of the shortcomings in terms of handling, performance, and serviceability. Other factors such as key design parameters (e.g., impact factor and thermal characteristics) and unexpected responses are used to further quantify the performance of four FRP representative deck systems under identical traffic and environmental constraints.     

Dynamic Response of Three Fiber Reinforced Polymer Composite Bridges

Fiber reinforced polymer (FRP) composite bridge decks are gaining the attention of bridge owners because of their light self-weight, corrosion resistance, and ease of installation. Constructed Facilities Center at West Virginia University working with the Federal Highway Administration and West Virginia Department of Transportation has developed three different FRP decking systems and installed several FRP deck bridges in West Virginia. These FRP bridge decks are lighter in weight than comparable concrete systems and therefore their dynamic performance is equally as important as their static performance. In the current study dynamic tests were performed on three FRP deck bridges, namely, Katy Truss Bridge, Market Street Bridge, and Laurel Lick Bridge, in the state of West Virginia. The dynamic response parameters evaluated for the three bridges include dynamic load allowance (DLA) factors, natural frequencies, damping ratios, and deck accelerations caused by moving test trucks. It was found that the DLA factors for Katy Truss and Market Street bridges are within the AASHTO 1998 LRFD specifications, but the deck accelerations were found to be high for both these bridges. DLA factors for Laurel Lick bridge were found to be as high as 93% against the typical design value of 33%; however absolute deck stress induced by vehicle loads is less than 10% of the deck ultimate stress.     

Strength and Serviceability of FRP Grid Reinforced Bridge Decks

The research presented in this paper evaluates the flexural performance of bridge deck panels reinforced with 2D fiber-reinforced polymer (FRP) grids. Two different FRP grids were investigated, one reinforced with a hybrid of glass and carbon fibers and a second grid reinforced with carbon fibers only. Laboratory measured load-deflection, load-strain (reinforcement and concrete), cracking, and failure behavior are presented in detail. Conclusions regarding failure mode, limit-state strength, serviceability, and deflection compatibility relative to AASHTO mandated criteria are reported. Test results indicate that bridge decks reinforced with FRP grids will be controlled by serviceability limit state and not limit-state ultimate strength. The low axial stiffness of FRP results in large service load flexural deflections and reduced shear strength. In as much as serviceability limits design, overreinforcement is recommended to control deflection violation. Consequently, limit-state flexural strength will be compression controlled for which reduced service stresses or ACI unified compression failure strength reduction factors are recommended.     

Service Load Effective Compression Flange Width in Fiber Reinforced Polymer Deck Systems Acting Compositely with Steel Stringers

This paper reports on the field study of a steel stringer-fiber reinforced polymer (FRP) deck composite bridge in Pennsylvania. The objective of the study is to assess the effective compression flange width in the FRP deck and floor systems when they act compositely with underlying steel girders at service conditions. The research results reported herein support the notion of employing a design approach, for both interior and exterior girders of a composite floor system, that is philosophically consistent with current practice related to steel girders acting compositely with concrete decking. It appears from the results presented herein that FRP decks and floors acting compositely with underlying steel girders exhibit an effective width that is close to the actual girder spacing for interior beams, and approximately one-half this value for exterior beams.     

Laboratory and Field Performance of Cellular Fiber-Reinforced Polymer Composite Bridge Deck Systems

This paper addresses the laboratory and field performance of multicellular fiber-reinforced polymer (FRP) composite bridge deck systems produced from adhesively bonded pultrusions. Two methods of deck contact loading were examined: a steel patch dimensioned according to the AASHTO Bridge Design Specifications, and a simulated tire patch constructed from an actual truck tire reinforced with silicon rubber. Under these conditions, deck stiffness, strength, and failure characteristics of the cellular FRP decks were examined. The simulated tire loading was shown to develop greater global deflections given the same static load. The failure mode is localized and dominated by transverse bending failure of the composites under the simulated tire loading as opposed to punching shear for the AASHTO recommended patch load. A field testing facility was designed and constructed in which FRP decks were installed, tested, and monitored to study the decks’ in-service field performance. No significant loss of deck capacity was observed after more than one year of field service. However, it was shown that unsupported edges (or free edges) are undesirable due to transitional stiffness from approach to the unsupported deck edge.     

FEA of Complex Bridge System with FRP Composite Deck

Innovative fiber-reinforced polymer (FRP) composite highway bridge deck systems are gradually gaining acceptance in replacing damaged/deteriorated concrete and timber decks. FRP bridge decks can be designed to meet the American Association of State Highway and Transportation Officials (AASHTO) HS-25 load requirements. Because a rather complex sub- and superstructure system is used to support the FRP deck, it is important to include the entire system in analyzing the deck behavior and performance. In this paper, we will present a finite-element analysis (FEA) that is able to consider the structural complexity of the entire bridge system and the material complexity of an FRP sandwich deck. The FEA is constructed using a two-step analysis approach. The first step is to analyze the global behavior of the entire bridge under the AASHTO HS-25 loading. The next step is to analyze the local behavior of the FRP deck with appropriate load and boundary conditions determined from the first step. For the latter, a layered FEA module is proposed to compute the internal stresses and deformations of the FRP sandwich deck. This approach produces predictions that are in good agreement with experimental measurements.     

Designing and Testing of Concrete Bridge Decks Reinforced with Glass FRP Bars

In addition to their high strength and light weight, fiber-reinforced polymer (FRP) composite reinforcing bars offer corrosion resistance, making them a promising alternative to traditional steel reinforcing bars in concrete bridge decks. FRP reinforcement has been used in several bridge decks recently constructed in North America. The Morristown Bridge, which is located in Vermont, United States, is a single span steel girder bridge with integral abutments spanning 43.90 m. The deck is a 230 mm thick concrete continuous slab over girders spaced at 2.36 m. The entire concrete deck slab was reinforced with glass FRP (GFRP) bars in two identical layers at the top and the bottom. The bridge is well instrumented at critical locations for internal temperature and strain data collection with fiber-optic sensors. The bridge was tested for service performance using standard truck loads. The construction procedure and field test results under actual service conditions revealed that GFRP rebar provides very good and promising performance.     

Fatigue Life Evaluation of Concrete Bridge Deck Slabs Reinforced with Glass FRP Composite Bars

Since bridge deck slabs directly sustain repeated moving wheel loads, they are one of the most bridge elements susceptible to fatigue failure. Recently, glass fiber-reinforced polymer (FRP) composites have been widely used as internal reinforcement for concrete bridge deck slabs as they are less expensive compared to the other kinds of FRPs (carbon and aramid). However, there is still a lack of information on the performance of FRP–reinforced concrete elements subjected to cyclic fatigue loading. This research is designed to investigate the fatigue behavior and fatigue life of concrete bridge deck slabs reinforced with glass FRP bars. A total of five full-scale deck slabs were constructed and tested under concentrated cyclic loading until failure. Different reinforcement types (steel and glass FRP), ratios, and configurations were used. Different schemes of cyclic loading (accelerated variable amplitude fatigue loading) were applied. Results are presented in terms of deflections, strains in concrete and FRP bars, and crack widths at different levels of cyclic loading. The results showed the superior fatigue performance and longer fatigue life of concrete bridge deck slabs reinforced with glass FRP composite bars.     

Deck-Mounted Steel Post Barrier System

An existing mountable safety barrier system, previously crash tested successfully on a wood bridge deck, was evaluated for use on a fiber reinforced plastic (FRP) bridge deck. In an attempt to avoid expensive full-scale crash testing, components of the existing system were evaluated using worst case conditions on two dynamic bogie crash tests and a series of computer simulations using nonlinear finite-element analysis. Simulation results closely approximated the physical results, with both displaying similar deformation, damage, and force levels. Both testing and simulation demonstrated that the barrier should function sufficiently if used on the FRP deck system. Further, the development of an accurate model makes it possible to evaluate the potential success of the existing system for use on other bridge decks. As an example, a more rigid bridge deck, similar to reinforced concrete, was evaluated. Results showed that due to the stiffer deck, more of the impact energy must be absorbed by the posts and attachment hardware, resulting in significantly more deformation than when used on the flexible FRP deck.     

Structural Behavior of FRP Composite Bridge Deck Panels

Fiber-reinforced polymer (FRP) composite bridge deck panels are high-strength, corrosion resistant, weather resistant, etc., making them attractive for use in new construction or retrofit of existing bridges. This study evaluated the force-deformation responses of FRP composite bridge deck panels under AASHTO MS 22.5 (HS25) truck wheel load and up to failure. Tests were conducted on 16 FRP composite deck panels and four reinforced concrete conventional deck panels. The test results of FRP composite deck panels were compared with the flexural, shear, and deflection performance criteria per Ohio Department of Transportation specifications, and with the test results of reinforced concrete deck panels. The flexural and shear rigidities of FRP composite deck panels were calculated. The response of all panels under service load, factored load, cyclic loading, and the mode of failure were reported. The tested bridge deck panels satisfied the performance criteria. The safety factor against failure varies from 3 to 8.     

Finite-Element Modeling and Development of Equivalent Properties for FRP Bridge Panels

Fiber-reinforced polymer (FRP) composite materials are increasingly making their way into civil engineering applications. To reduce the self-weight and also achieve the necessary stiffness, sandwich panels are commonly used for FRP bridge decks. However, due to the geometric complexity of the FRP sandwich deck, convenient analysis and design methods for FRP bridge deck have not been developed. The present study aims at developing equivalent properties for a complicated sandwich panel configuration using finite-element modeling techniques. With equivalent properties, the hollowed sandwich panel can be transformed into an equivalent solid orthotropic plate, based on which deflection limits can be evaluated and designed. A procedure for the in-plane axial properties of the sandwich core has first been developed, followed by developing the out-of-plane panel properties for bending behavior of the panel. An application is made in the investigation of the stiffness contribution of wearing surface to the total stiffness of bridges with FRP panels. The wearing surface contribution is not usually accounted for in a typical design of bridges with traditional deck systems.     

Evaluation of Composite Sandwich Bridge Decks with Hybrid FRP-Steel Core

A hybrid concept of composite sandwich panel with hybrid fiber-reinforced polymer (FRP)—steel core was proposed for bridge decks in order to not only improve stiffness and buckling response but also be cost efficient compared to all glass fiber-reinforced polymer (GFRP) decks. The composite sandwich bridge deck system is comprised of wrapped hybrid core of GFRP grid and multiple steel box cells with upper and lower GFRP facings. Its structural performance under static loading was evaluated and compared with the ANSYS finite element predictions. It was found that the presented composite sandwich panel with hybrid FRP-steel core was very efficient for use in bridges. The thickness of the hybrid deck may be decreased by 19% when compared with the all GFRP deck. The failure mode of the proposed hybrid deck was more favorable because of the yielding of the steel tube when compared with that of all GFRP decks.     

Sustained-Load and Fatigue Performance of a Hybrid FRP-Concrete Bridge Deck System

The design and construction of bridge systems with long-term durability and low maintenance requirements is a significant challenge for bridge engineers. One possible solution to this challenge could be through the use of new materials, e.g., fiber-reinforced polymer (FRP) composites, with traditional materials that are arranged as an innovative hybrid structural system where the FRP serves as a load-carrying constituent and a protective cover for the concrete. This paper presents the results of an experimental investigation designed to evaluate the performance of a 3/4 scale hybrid FRP-concrete (HFRPC) bridge deck and composite connection under sustained and repeated (fatigue) loading. In addition, following the sustained-load and fatigue portions of the experimental study, destructive testing was performed to determine the first strength-based limit state of the hybrid deck. Results from the sustained-load and fatigue testing suggest that the HFRPC deck system might be a viable alternative to traditional cast-in-place reinforced concrete decks showing no global creep behavior and no degradation in stiffness or composite action between the deck and steel girders after 2 million cycles of dynamic loading with a peak load of 1.26 times the scaled tandem load (TL). Furthermore, the ultimate strength test showed that the deck failed prior to the global superstructure at a load approximately six times the scaled TL.     

Compound Shear-Flexural Capacity of Reinforced Concrete–Topped Precast Prestressed Bridge Decks

Modern concrete bridge decks commonly consist of stay-in-place (SIP) precast panels seated on precast concrete beams and topped with cast-in-place (CIP) reinforced concrete. Such composite bridge decks have been experimentally tested by various researchers to assess structural performance. However, a failure theory that describes the failure mechanism and accurately predicts the corresponding load has not been previously derived. When monotonically increasing patch loads are applied, delamination occurs between the CIP concrete and SIP panels, with a compound shear-flexure mechanism resulting. An additive model of flexural yield line failure in the lower SIP precast prestressed panels and punching shear in the upper CIP-reinforced concrete portion of the deck system is derived. Analyses are compared to full-scale experimental results of a tandem wheel load straddling adjacent SIP panels and a trailing wheel load on a single panel. Alone, both yield line and punching-shear theories gave poor predictions of the observed failure load; however, the proposed compound shear-flexure failure mechanism load capacities are within 2% accuracy of the experimentally observed loads. Better estimation using the proposed theory of composite SIP-CIP deck system capacities will aid in improving the design efficiency of these systems.     

Flexural Lateral Load Distribution Characteristics of Sandwich Plate System Bridges: Parametric Investigation

The sandwich plate system (SPS) is a relatively new bridge deck system that consists of steel face plates bonded to a rigid polyurethane core. The decks are thin, lightweight, and modular in design and can be tailored to numerous applications. This system provides an excellent alternative for the rapid construction and rehabilitation of bridge decks. With any new system, there exists some uncertainty in the design procedures as a result of the limited population for comparison. This paper presents the results of a finite-element parametric investigation of the lateral load distribution characteristics of SPS bridges. The parametric study primarily focuses on the influence of deck thickness on distribution behavior as compared to conventional reinforced concrete decks. Results from the study demonstrate that the inherent flexibility of a thin SPS deck yields larger distribution factors (up to 20%) than a typical reinforced concrete deck, but these distribution factors can still be conservatively estimated with current AASHTO LRFD methods. Additional comparisons indicate that the distribution behavior of SPS bridges can also be estimated with the equations proposed by the NCHRP 12-62 project.     

Failure Study of an Aluminum Bridge Deck Panel

Aluminum bridge decks may prove to be an alternative to concrete decks for improving the performance of structural bridge systems. Combining excellent corrosion resistance with extremely low density, aluminum decks can prolong surface life, facilitate the construction process, and expand rehabilitation capabilities. Reynolds Metals Company, Richmond, Va., has invested considerable resources to develop a proprietary aluminum deck system. The Virginia Department of Transportation agreed to employ the Reynolds deck system in two projects. Using Federal Highway Administration sponsorship, the Virginia Transportation Research Council initiated a study to evaluate the aluminum deck system. The first phase of this project analyzed the static response of a 2.74 × 3.66 m (9 × 12 ft) deck panel. Both service-load tests and ultimate-load tests were performed on the panel at the Turner-Fairbank Structural Laboratory. The experimental and analytical evaluation of the ultimate load static tests is the subject of this paper. The failure load and failure mechanism were predicted with great accuracy. The model data predicted panel failure at a load of 911.89 kN (205 kips) by yielding under the load patch while failure during the laboratory test occurred at a load of 872.07 kN (196.05 kips) by gross yielding underneath the load patch.     

Acoustic Emission Monitoring and Analysis of Glass Fiber-Reinforced Composites Bridge Decks

The application of fiber-reinforced composites (FRP) is gaining momentum as an alternative material for bridge replacement, repair, and rehabilitation. While a number of states now use FRP, a lack of standards, codes, and performance data for FRP bridge decks has resulted in the use of FRP technology not being widely accepted. This paper presents the performance results, based on acoustic emission (AE), of six full-scale glass FRP bridge deck panels with nominal cross-sectional depths varying from 152 mm (6 in.) to 800 mm (30 in.). The objective was to develop for use during in-service field inspections an AE monitoring strategy that will determine the structural performance of the deck. As such, the characterization of damage, e.g., fiber breakage, matrix cracking, and delamination, was part of the investigated criteria and the contributing factors for identification of a monitoring strategy. Although some factors were determined to be associated with the performance evaluation of the structural integrity of the decks, further investigation is needed.     

Performance of Coated Reinforcing Bars in Cracked Bridge Decks

The presence of cracks in bridge decks that are reinforced with epoxy-coated reinforcing (ECR) bars has raised some concerns among bridge and maintenance engineers in the state of Iowa. To study the effects of deck cracking on the performance of ECR bars, several concrete cores that contained reinforcing bars were collected from 80 bridges that are located in different counties throughout the state of Iowa. These samples were collected from cracked and uncracked areas of the bridge decks. Concrete powder samples were collected from these cores and were analyzed in the laboratory to determine the diffusion of the chloride in the bridge decks. This study revealed that no sign of corrosion was detected for the ECR rebars that were taken at the uncracked bridge deck locations. In addition, no delamination or spalling was observed for the bridge decks where bars in the core samples, which were taken at the cracked bridge deck locations, exhibited signs of corrosion. The collected ECR rebars samples were rated according to the degree of the corrosion that was observed on each bar. These ratings were used to develop condition/age relationships that were utilized to estimate the functional service life of bridge decks that are reinforced with ECR bars.     

Characterization of a Low-Profile Fiber-Reinforced Polymer Deck System for Moveable Bridges

Moveable bridges in Florida typically use open steel grid decks due to weight limitations. However, these decks present rideability, environmental, and maintenance problems, as they are typically less skid resistant than a solid riding surface, create loud noises, and allow debris to fall through the grids. Replacing open steel grid decks with a lightweight fiber-reinforced polymer (FRP) deck can improve rideability and reduce maintenance costs, simultaneously satisfying the strict weight requirement for such bridges. In this investigation, a new low-profile, pultruded FRP deck system successfully passed the preliminary strength and fatigue tests per AASHTO requirements. Two two-span deck specimens were tested, one with the strong direction of the deck placed perpendicular to the supporting girders, whereas the other had a deck placed with 30° skew. This paper also describes a simplified finite-element approach that simulates the load–deformation behavior of the deck system. The results from the finite-element model showed a good correlation with the deflection and strain values measured from the tests.