Fiber-reinforced Polymer Composite Bridge Research Articles

Fiber-Reinforced Polymer Composites in the Construction of Bridges: Opportunities, Problems and Challenges

In this review, we discuss the basic issues related to the use of FRP (fiber-reinforced polymer) composites in bridge construction. This modern material is presented in detail in terms of the possibility of application in engineering structures. A general historical outline of the use and development of modern structural materials, such as steel and concrete, is included to introduce composites as a novel material in engineering, and the most important features and advantages of polymers as a construction material are characterized. We also compare FRP to basic structural materials, such as steel and concrete, which enables estimation of the effectiveness of using of FRP polymers as structural material in different applications. The first bridges made of FRP composites are presented and analyzed in terms of applied technological solutions. Examples of structural solutions for deck slabs, girders and other deck elements made of FRP composites are discussed. Particular attention is paid to the systems of deck slabs, especially those composed of pultruded profiles, sandwich panels and hybrid decks. The disadvantages of composites, as well as barriers and limitations in their application in engineering practice, are presented. Exemplary analyses of the costs of construction, maintenance and demolition of FRP composite bridges are presented and compared with the corresponding costs of concrete and steel bridges. The directions of development of composite bridge structures and the greatest challenges facing engineers and constructors in the coming years are discussed.

Fiber Reinforced Polymer Culvert Bridges—A Feasibility Study from Structural and LCC Points of View

Soil–steel composite bridges (SSCB) have become increasingly popular for short-span bridges as an alternative to concrete slab bridges mainly due to their low initial cost, rapid manufacture, simplified construction, and geometrical adaptability. SSCBs have a variety of applications and can be used over waterways or roadways. While conventional bridges tend to lose their load-carrying capacity due to degradation, SSCBs gain strength because of backfill soil consolidation. However, the load carrying capacity and integrity of such structures highly depends on the condition and load-carrying capacity of the steel arch element. A major drawback of SSCBs, especially those located on waterways or with poor drainage, is corrosion and subsequent loss of cross-sectional capacity. Unfortunately, the inspection of such bridges is not straightforward and any damage/collapse will be very costly to repair/replace. Fiber reinforced polymer (FRP) composites offer an attractive alternative to replace the steel in these types of bridges. FRP composites have significantly improved durability characteristics compared to steel, which will reduce maintenance costs and improve life-cycle costs (LLCs). This paper presents a new concept to use glass FRP as a construction material to construct soil–FRP composite bridges (SFCB). Various aspects of design and manufacturing are presented along with results and conclusions from a case study involving alternative bridge designs in steel and FRP composites.

Distributed fibre optic sensors in FRP composite bridge monitoring: Validation through proof load tests

The distributed fibre optic sensors (DFOS) technique based on Rayleigh scattering has been chosen as the basic structural health monitoring (SHM) system of the first Polish fibre reinforced polymer (FRP) composite bridge. The validation of the DFOS technique is critical to address the development of a monitoring system with improved accuracy and spatial resolution tailored for the FRP bridge application. The validation through proof load tests and finite element analysis (FEA) has been performed to ensure accurate and reliable DFOS readings. Two additional strain measurements techniques were implemented to validate DFOS, i.e. common foil strain gauges and vibrating wire strain gauges. The DFOS strain profiles were first compared with discrete strain measurements and then converted into deflection profiles and validated against discrete deflection measurements performed with common linear variable differential transducers. The additional validation based on the comparison of the measurement profiles with the results of FEA has been also performed. Based on the experimental and numerical results it has been revealed the DFOS technique is a reliable and accurate method to be implemented for FRP bridge monitoring.

A multivariate adaptive regression splines based damage identification methodology for web core composite bridges including the effect of noise

A novel computationally efficient damage identification methodology for web core fiber-reinforced polymer composite bridges has been developed in this article based on multivariate adaptive regression splines in conjunction with a multi-objective goal-attainment optimization algorithm. The proposed damage identification methodology has been validated for several single and multiple damage cases. The performance of the efficient multivariate adaptive regression splines-based approach for the inverse system identification process is found to be quite satisfactory. An iterative scheme in conjunction with the multi-objective optimization algorithm coupled with multivariate adaptive regression splines is proposed to increase damage identification accuracy. The effect of noise on the proposed damage identification algorithm has also been addressed subsequently using a probabilistic framework. The multivariate adaptive regression splines-based damage identification algorithm is general in nature; therefore, in future it can be implemented to other structures.

Optimisation of Fibre-Reinforced Polymer Web Core Bridge Deck—A Hybrid Approach

This paper presents a novel hybrid technique based on D-optimal design and Nelder–Mead simplex algorithm for optimisation of fibre-reinforced polymer (FRP) composite web core bridge deck panels. The optimisation is performed to minimise the weight of FRP composite bridge deck panels based on deflection limit, stresses, buckling and failure analysis, and subsequently the representative design curves are developed. Sensitivity analysis is performed to portray the effect of variation in geometry of the bridge deck on its deflection, stress and buckling behaviours.

Structural Damage Identification Using Response Surface-Based Multi-objective Optimization: A Comparative Study

Non-destructive structural damage identification (SDI) and quantification of damage are important issues for any engineering structure. In this study, a comparative assessment of the damage identification capability of different design of experiment (DOE) methods (such as, 2 k factorial design, central composite design, Box–Behnken design, D-optimal design and Taguchi’s OA design) used in response surface methodology (RSM) has been carried out. Three different structures (simply supported beam, spring mass damper system and fibre reinforced polymer composite bridge deck) have been used for various single and multiple damage conditions to access the comparative ability of the aforementioned methods in identifying damage addressing two critically important criteria: accuracy and computational efficiency. The study reveals that central composite design and D-optimal design are most recommendable among the five considered DOE methods for SDI. Two different input parameter screening methods (sensitivity analysis using RSM utilizing 2 k factorial design and D-optimal design, general sensitivity analysis) have been explored in this study, and their comparative performance is also discussed. It is found that both the methods used in sensitivity analysis for the purpose of input parameter screening in the damage identification process work satisfactorily. Performance of RSM-based damage identification algorithm for different DOE methods under the influence of noise has also been addressed in this paper.

Simplified load distribution factors for fiber reinforced polymer composite bridge decks

In recent years, researchers have investigated the load distribution factors due to vehicle wheel loads. Several load distribution factors for fiber reinforced polymer deck-steel stringer bridge systems have been proposed. Unfortunately, these load distribution factors are only used for each particular fiber reinforced polymer bridge deck system. Therefore, the objective of the research effort is to present the load distribution results of a parametric study using finite element analysis. The simplified load distribution factors were developed herein. The bridge parameters for this study were stringer spacing, bridge span, width of bridge models, types of fiber reinforced polymer bridge decks and numbers of traffic lanes. The bridge responses under various wheel loading conditions were investigated. The simplified distribution factors based on “S-over-factor” formula were proposed and compared with the load distribution factors obtained from specifications, analytical and field data. The load distribution results for this present study were correlated to the previous research data. The upper and lower bound limit of the load distribution factors were presented to purpose of preliminary guidelines.

Structural performance of light weight multicellular FRP composite bridge deck using finite element analysis

Fiber reinforced polymer (FRP) composite materials having advantages such as higher strength to weight than conventional engineering materials, non-corrosiveness and modularization, which should help engineers to obtain more efficient and cost effective structural materials and systems. Currently, FRP composites are becoming more popular in civil engineering applications. The objectives of this research are to study performance and behavior of light weight multi-cellular FRP composite bridge decks (both module and system levels) under various loading conditions through finite element modeling, and to validate analytical response of FRP composite bridge decks with data from laboratory evaluations. The relative deflection, equivalent flexural rigidity, failure load (mode) and load distribution factors (LDF) based on FE results have been compared with experimental data and discussed in detail. The finite element results showing good correlations with experimental data are presented in this work.

Moisture diffusion in glass–fiber-reinforced polymer composite bridge under hot/wet environment

In literatures, researches on degradation of composites due to environmental effects were well documented on fiber-reinforced polymer (FRP) composites for Aerospace Engineering; for FRP composites utilized in Civil Engineering field, the available information was very limited. In order to keep pace with the application of FRP composites in Civil Engineering field, this research was undertaken to reveal more knowledge about the environmental degradation of FRP composite bridge under hot/wet environment. By gravimetric experiments, the moisture diffusion in thin-section of FRP composites and adhesives were characterized. Based on the analytical model of one-dimensional moisture diffusion theory, the diffusion coefficients were determined by the best least-square curve fitting to the experimental data. The finite element (FE) models of test specimens were developed and validated against experimental results. Through transient FE diffusion analysis, the moisture diffusion into the FRP-steel composite bridge deck system under a hot/wet environment was numerically predicted up to 100-year aging duration. The moisture uptake in adhesive connection was fully saturated after 26-year aging. The area between FRP composite sections and the adhesive layer was confirmed to be the most sensitive part to moisture effects. This research developed a step towards the prediction of long-term performance and life-time estimation of FRP-steel composite bridges.

Live Load Distribution of Hybrid Fiber-Reinforced Polymer Composite Superstructure on the Basis of Field Test

Transverse live load distribution in a concrete–fiber-reinforced polymer (FRP) composite hybrid bridge was investigated both experimentally and analytically. The subject bridge was a concrete–FRP composite hybrid bridge, constructed with four 31-ft (9.4-m) long, prefabricated superstructure panels, which were joined along longitudinal field joints made of steel-reinforced grout. The live load distribution factors (DFs) of this bridge were evaluated with strain values measured in field tests and produced from finite element analysis. Design documents and load rating reports showed that a simplified method on the basis of beam-bending could be used in the design process, which required live load DFs. From strain values measured during load tests, the DFs were inferred to be 0.35 and 0.49 for interior and exterior panels, respectively. The comparison of load tests done 6 years apart indicated no significant change in the structural performance of the bridge. Although the design of this structure was unique, the evaluation showed that other hybrid structural members also could achieve good load distribution. The investigation indicated that composite structures could be durable with little maintenance required.

Load and resistance factor design of fiber reinforced polymer composite bridge deck

The majority of our bridges were constructed with conventional civil engineering materials of steel and concrete in a typical slab on girder or truss construction. Reinforced concrete bridge decks have approximately 40% life of the steel girders that support these structures. In order to support the use of alternative materials to replace deteriorating concrete decks, this paper outlines the Load and Resistance Factor Design (LRFD) of Fiber Reinforced Polymer composite (FRP) panel highway bridge deck. The deck would be of a sandwich construction where 152.4mm×152.4mm×9.5mm square pultruded glass FRP (GFRP) tubes are joined and sandwiched between two 9.5mm GFRP plates. The deck would be designed by Allowable Stress Design (ASD) and LRFD to support AASHTO design truckload HL-93. There are currently no US standards and specifications for the design of FRP pultruded shapes including a deck panel therefore international codes and references related to FRP profiles will be examined and AASHTO-LRFD specifications will be used as the basis for the final design. Overall, years of research and laboratory and field tests have proven FRP decks to be a viable alternative to conventional concrete deck. Therefore, conceptualizing the design of FRP bridge decks using basic structural analysis and mechanics would increase awareness and engineering confidence in the use of this innovative material.

A comparative study on static and dynamic responses of FRP composite and steel suspension bridges

Fiber reinforced polymer (FRP) composites offer many attractive and unique features for existing and new bridges. Among these features are light weight, high stiffness-to-weight and strength-to-weight ratios, damping capabilities, and high resistance to environmental degradation when properly designed and installed. This article presents a pilot numerical study aiming at evaluating the feasibility of using FRP composites in suspension bridge applications. This was accomplished by comparing the response of two identical long-span suspension bridges, one constructed from FRP composite and the other made of steel under static and dynamic loadings using FEM. The numerical results indicated that the responses of the two bridges are different and that the response values obtained for the steel bridge are relatively large compared to the composite bridge. Despite different mode sequences of the two bridge models, the dynamic analysis results indicated that both bridge models have similar mode shapes. As a result of lower self-weight of the FRP composite bridge model, the frequencies of the FRP composite bridge model are larger than those of the steel bridge model.

Field Issues Associated with the Use of Fiber-Reinforced Polymer Composite Bridge Decks and Superstructures in Harsh Environments

There has been ample time for the United States to evaluate the use of fiber-reinforced polymer (FRP) composites to serve as bridge decks and superstructures under real-world environmental and operating conditions. This provides a great opportunity to weigh in on the decision to move forward with these materials. By studying the successes and failures, materials and techniques used for the design and construction of these bridges can be improved so that we can move closer to the goals of maintenance-free bridges and service lives exceeding 100 years. Though only a few of these structures are instrumented for structural health monitoring, there are a sufficient number of lessons that can be gleaned from the experiences of various owners during the fabrication, installation, operation, and inspection of these structures. By addressing these issues head-on, advocates will be better equipped to have direct dialogue with those in the profession who remain skeptical about the hidden potential for a construction material that is strong, light, and corrosion resistant.

Direct load transmission in hybrid FRP and lightweight concrete sandwich bridge deck

Direct load transmission experiments on hybrid short-span beam specimens for a novel bridge deck were performed. The sandwich construction consists of three layers: a fiber-reinforced polymer composite (FRP) sheet with T-upstands for the bottom skin, lightweight concrete (LC) for the core and a thin layer of ultra high performance reinforced concrete as a top skin. Specimens with adhesively bonded FRP–LC interfaces showed significantly higher ultimate loads than corresponding unbonded specimens with composite action due to pure mechanical interlocking. The degree of composite action between FRP and LC in the unbonded interfaces depended on the LC compressive strength. A correlation of the specimen ultimate loads and the LC splitting tensile strengths was found. Combining the LC splitting tensile strength and the LC characteristic length led to a good correlation with the specimen cracking loads.

Progress of advanced composites for civil infrastructure

The current paper describes the use of fibre reinforced polymer (FRP) composites as primary structural members. In particular FRP composite bridge decks are discussed and the Asset project, which comprised the development of a FRP composite bridge deck system, is described in detail. The analysis, design and testing undertaken within the project are also discussed in detail. The culmination of the project, the reconstruction of West Mill Bridge in Oxfordshire, is described and conclusions made on the particular advantages of using FRP composites for bridge decks.

Detection of subsurface defects in fiber reinforced polymer composite bridge decks using digital infrared thermography

Fiber reinforced polymer (FRP) bridge decks are rapidly emerging as potential alternatives to conventional reinforced concrete (RC) bridge decks. The FRP decks offer higher strength-to-weight ratios compared to RC decks. However, presence of subsurface defects such as debonds and delaminations formed during initial construction and in service can adversely affect the structural integrity and service performance of the FRP bridge decks. Hence, a field monitoring technique such as infrared thermography is required to evaluate the in situ condition of these FRP decks. This paper investigates the use of digital infrared thermography for subsurface defect detection in FRP bridge decks. Air-filled and water-filled debonds were inserted between the wearing surface and the underlying FRP deck in the laboratory. Simulated subsurface delaminations (of various sizes and thickness) were also created at the flange-to-flange junction between two FRP deck modules. The infrared technique was used to detect these embedded subsurface defects. Surface temperature–time curves were established for different sizes of delaminations and debonds. In addition, field study was conducted on a FRP bridge deck to detect debonds between the wearing surface and the underlying deck. The laboratory and field testing results show that infrared thermography is a potentially useful tool for defect detection in FRP composite bridge decks. The technique can possibly be used for several applications such as quality control during pultrusion of new decks (in factories), during field construction, and for field inspection of in-service decks.

Fatigue durability of FRP composite bridge decks at extreme temperatures

Decks manufactured with Fibre-Reinforced Polymer (FRP) composite materials are used in bridges. A performance evaluation of FRP composite decks subjected to simulated traffic loads that induce repetitive stress cycles under extremely high and low temperature is presented. Fatigue testing of three FRP composite bridge deck prototypes and one FRP-concrete hybrid bridge deck prototype under two extreme temperature conditions: −30°C (−22°F), and 50°C (122°F) was conducted. The fatigue response of the deck prototypes was correlated with the baseline performance of a conventional reinforced-concrete deck. Design loads were applied simultaneously at two points. Quasi-static load-deflection and load-strain characteristics were determined at predetermined fatigue cycle levels. No significant distress was observed in any of the composite deck prototypes during ten million load cycles. The effects of extreme temperatures and accumulated load cycles on the load-deflection and load-strain response of FRP composite and FRP-concrete hybrid bridge decks are discussed based on the experimental results.

Durability of FRP composite bridge decks construction and temperature effects

During the past several years, a relatively large body of research has been directed toward better understanding of behaviour of civil infrastructure employing Fibre-Reinforced Polymer (FRP) composites, and for development of design guidelines. Nevertheless, these studies have generally ignored or marginally evaluated the reaction of structural systems using FRP to the environment, most importantly temperature changes, and loads to which civil engineering structures are subjected. Using an extensive array of instruments and field as well as laboratory tests, the short-term and long-term performances of four types of FRP composite bridge decks were recently evaluated. The coefficient of thermal expansion and the level of temperature gradient were found to be higher than those of standard reinforced concrete decks. Lack of attention to detailing and thermal characteristics of individual components as well as the entire FRP deck system can lead into build up of large thermal gradients, which can result in unexpected deformations and damage. To ensure satisfactory performance, thermal behaviour and the resulting thermal stresses need to be incorporated into design and detailing of panel-girder connections, field joints, and face sheet-core connection in sandwich type panels. Based on the presented information, a number of recommendations for improved behaviour are made.

Reliability-Based Optimization of Fiber-Reinforced Polymer Composite Bridge Deck Panels

A reliability-based optimization procedure is developed and applied to minimize the weight of eight fiber-reinforced polymer composite bridge deck panel configurations. The method utilizes interlinked finite element, optimization, and reliability analysis procedures to solve the weight minimization problem with a deterministic strength constraint and two probabilistic deflection constraints. Panels are composed of an upper face plate, lower face plate, and a grid of interior stiffeners. Different panel depths and stiffener layouts are considered. Sensitivity analyses are conducted to identify significant design and random variables. Optimization design variables are panel component ply thicknesses, while random variables include load and material resistance parameters. It was found that panels were deflection governed, with the optimization algorithm yielding little improvement for shallow panels, but significant weight savings for deeper panels. The best design resulted in deep panels with close stiffener spacing to minimize local upper face plate deformations under the imposed traffic (wheel) loads.

Flexural behavior of a hybrid FRP and lightweight concrete sandwich bridge deck

This paper presents a new concept for a lightweight hybrid-FRP bridge deck. The sandwich construction consists of three layers: a fiber-reinforced polymer composite (FRP) sheet with T-upstands for the tensile skin, lightweight concrete (LC) for the core and a thin layer of ultra high performance reinforced concrete (UHPFRC) as a compression skin. Mechanical tests on eight hybrid beams were performed with two types of LC and two types of FRP/LC interface: unbonded (only mechanical interlocking of LC between T-upstands) and bonded with an epoxy adhesive. The ultimate loads of the beams increased by 104% on average due to bonding. However, the beam failure mode changed from ductile to brittle. The beams using a LC of 44% higher density exhibited an 81% increase in the ultimate load. The manufacturing of the beams proved to be economic in that epoxy and concrete layers were rapidly and easily applied wet-in-wet without intermediate curing times. The experimental results showed positive results regarding the feasibility of the suggested hybrid bridge deck.