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Wind energy is widely deployed and will likely grow in service of reducing the world's dependency on fossil fuels. The first generation of wind turbines are now coming to the end of their service lives, and there are limited options for the reuse or recycling of the composite materials they are made of. Current literature has verified that there is no existing recycling pathway (i.e., mechanical, chemical, thermal methods of recovery, etc.) for end-of-life materials in wind blades that can meet cost parity with landfilling in the US. However, to the authors' knowledge there is no study to date that uncovers the cost structures associated with repurposing wind turbine blades in the US. Repurposing could offer a cost-competitive advantage through displacement of higher-value products, rather than materials or chemical constituents alone. This study implements life cycle assessment (LCA) and life cycle cost analysis (LCC) to assess the environmental and financial implications at each stage of repurposing wind turbine blades as the primary load-carrying elements for high-voltage transmission line structures in the United States. This case study contribution to knowledge is based on the successful management of construction waste by analyzing an application for repurposing construction demolition waste. Specifically, this study presents an environmental and financial analysis of repurposing wind turbine blades as transmission line poles. Under this case study, our results show that BladePoles have lower greenhouse gas emissions than steel poles, and we anticipate BladePoles will be less costly than steel poles. Overall emissions are most sensitive to combustion emissions, driven primarily by transportation distance and hours of required crane operations during the installation process. Compared to other evaluated recycling methods, repurposing wind blades as BladePoles has the least overall global warming potential. As renewable energy production grows, managing infrastructure at its end-of-life is increasingly relevant—for example, wind turbine blades. This case study presents a financial and environmental analysis of repurposing decommissioned wind turbine blades as transmission poles, called BladePoles. This paper presents the cost and associated greenhouse gas emissions at each stage of the process. The case study also compares this reuse application to typical steel pole deployment, finding that for the same 60-year life span and 161 kV, 230 kV, and 345 kV transmission line poles, the BladePole cost is lower than the steel pole. Greenhouse gas emissions are most sensitive to transportation distance from the wind farm to the transmission project and the time of crane use for installation are key parameters in this case study and reducing them directly reduces the total greenhouse emissions overall. [ABSTRACT FROM AUTHOR]

In recent years, the sustainability of wind power has been called into question because there are currently no truly sustainable solutions to the problem of how to deal with the non-biodegradable fibre-reinforced polymer (FRP) composite wind blades (sometimes referred to as "wings") that capture the wind energy. The vast majority of wind blades that have reached their end-of-life (EOL) currently end up in landfills (either in full-sized pieces or pulverized into smaller pieces) or are incinerated. The problem has come to a head in recent years since many countries (especially in the EU) have outlawed, or expect to outlaw in the near future, one or both of these unsustainable and polluting disposal methods. An increasing number of studies have addressed the issue of EOL blade "waste"; however, these studies are generally of little use since they make predictions that do not account for the manner in which wind blades are decommissioned (from the time the decision is made to retire a turbine (or a wind farm) to the eventual disposal or recycling of all of its components). This review attempts to lay the groundwork for a better understanding of the decommissioning process by defining how the different EOL solutions to the problem of the blade "waste" do or do not lead to "sustainable decommissioning". The hope is that by better defining the different EOL solutions and their decommissioning pathways, a more rigorous research base for future studies of the wind blade EOL problem will be possible. This paper reviews the prior studies on wind blade EOL and divides them into a number of categories depending on the focus that the original authors chose for their EOL assessment. This paper also reviews the different methods chosen by researchers to predict the quantities of future blade waste and shows that depending on the choice of method, predictions can be different by orders of magnitude, which is not good as this can be exploited by unscrupulous parties. The paper then reviews what different researchers define as the "recycling" of wind blades and shows that depending on the definition, the percentage of how much material is actually recycled is vastly different, which is also not good and can be exploited by unscrupulous parties. Finally, using very recent proprietary data (December 2022), the paper illustrates how the different definitions and methods affect predictions on global EOL quantities and recycling rates. [ABSTRACT FROM AUTHOR]

Millions of tons of glass-fiber-reinforced polymer (GFRP) composite wind turbine blades are expected to age out of service over the next 30 years. Research is being conducted on repurposing these structures as new civil infrastructure products. The GFRP material in these decommissioned wind blades has been shown to retain significant strength and stiffness for second-life applications. However, for repurposing as new products, they will need to be connected to other structural members. The connections employed for this need to be designed, evaluated, and tested prior to their use. Here, we present the results of detailed testing of bolted connections for load-carrying appurtenances that will carry the phases and shield wires (e.g., insulators, crossarms, davits, guy wires, posts) to the spar cap of an 11-year-old 1.5 MW GE37 wind blade, intended for use as a repurposed transmission pole (i.e., a BladePole). Details of ASTM-type pull-out and bearing capacity tests using different types of blind bolts, and tests of a full-scale steel bracket connection called a "universal connector," are reported. The effects of the different blind bolts, pin diameters, and loading directions relative to the composite laminate structure (longitudinal or transverse) for both the coupon- and full-scale connector bracket tests are described. The ability to design and construct robust connections for repurposed wind blade structures was demonstrated. [ABSTRACT FROM AUTHOR]

This paper describes repurposing projects using decommissioned wind turbine blades in bridges conducted under a multinational research project entitled "Re-Wind". Repurposing is defined by the Re-Wind Network as the re-engineering, redesigning, and remanufacturing of a wind blade that has reached the end of its life on a turbine and taken out of service and then reused as a load-bearing structural element in a new structure (e.g., bridge, transmission pole, sound barrier, seawall, shelter). The issue of end-of-life of wind turbine blades is becoming a significant sustainability concern for wind turbine manufacturers, many of whom have committed to the 2030 or 2040 sustainability goals that include zero-waste for their products. Repurposing is the most sustainable end-of-life solution for wind turbine blades from an environmental, economic, and social perspective. The Network has designed and constructed two full-size pedestrian/cycle bridges—one on a greenway in Cork, Ireland and the other in a quarry in Draperstown, Northern Ireland, UK. The paper describes the design, testing, and construction of the two bridges and provides cost data for the bridges. Two additional bridges that are currently being designed for construction in Atlanta, GA, USA are also described. The paper also presents a step-by-step procedure for designing and building civil structures using decommissioned wind turbine blades. The steps are: project planning and funding, blade sourcing, blade geometric characterization, material testing, structural testing, designing, cost estimating, and construction. [ABSTRACT FROM AUTHOR]

Self-drilling screws provide an efficient and cost-effective way of joining lightweight structural members. In this work, the performance of self-drilling screw connections for fiber-reinforced polymer (FRP) structural members is investigated, for use in joining panels or plates to square hollow sections (SHSs). To investigate the resistance to pullout loads, tensile tests were conducted on connection specimens consisting of an FRP plate joined to an FRP SHS at a right angle. The specimens were prepared in five configurations, with differences in pultrusion directions of the FRP plate, screw gauge size, and coarseness of the screw threads. The specimens having fibers oriented transversely in the FRP plate exhibited a flexural failure of the plate and the lowest connection strength. The specimens having fibers oriented longitudinally in the FRP plate failed by the screw being pulled out from the FRP SHS profiles; shearing out of the thread in the screw hole. An increase in screw gauge size and thread coarseness was found to be beneficial to the connection strength. Further analysis was carried out to estimate the initial stiffness and the connection strength, by finite-element and analytical modeling, respectively. In addition, these analyses are able to correlate the average shear stress at failure of the connection specimens to the screw gauge size, thread coarseness, and effective contact area of the screws. [ABSTRACT FROM AUTHOR]

E-glass fiber-reinforced polymer (FRP) composite wind turbine blades are nonbiodegradable, and their end-of-life recycling solutions are limited. Research on reusing and repurposing applications, where minimal amounts of refabrication are needed, is being conducted to address this issue. To design new structures from decommissioned blades, their as-received mechanical and physical properties are needed. Even though some long-term property data for FRP composites exist in the literature, very little actual data for the as-received residual properties of decommissioned blades have been reported. The current work is aimed at developing a methodology to obtain as-received material property data for decommissioned wind turbine blades that are being proposed for use as second-life structural components. In this paper, details of the methods used and the test results for the key physical and mechanical properties of glass FRP material specimens extracted from the spar cap of a decommissioned 1.5-MW GE37 wind turbine blade are reported (the blade is from a General Electric 1.5 MW turbine which is known as a GE37 blade), including burnout testing for constituents' weight and volume fractions as well as fiber architecture and tension, compression, and shear testing in the longitudinal and transverse material directions. Comparisons between test results of other investigators and the experimental data obtained show promising strength and stiffness retention levels of the material for different properties. The results show that structural integrity still exists for the tested composite materials and no deterioration, crack propagation, or delamination was observed in the materials due to the cyclic loading levels experienced in their first life. [ABSTRACT FROM AUTHOR]

Fiber-reinforced polymer (FRP) pultruded profiles are produced by a number of manufacturers worldwide in similar, but nonstandard, wide-flange, I, angle, and tubular profiles. At present there is no American National Standards Institute approved design code in the United States for structural design with pultruded FRP profiles. Manufacturers of pultruded profiles each provide their own design equations, design methods, material properties, and safety factors for their pultruded products. There is a need for standardization of production and design of pultruded profiles to enable mainstream use of these profiles in structural engineering practice. The purpose of this paper is twofold: (1) to provide appropriate resistance factors (0 factors) for wide-flange pultruded columns that are compatible with ASCE 7 load factors and (2) to provide a unified analytical equation for local and global buckling of concentrically loaded axial members, which may be appropriate for a future design code. The resistance factors are provided for different target levels of structural reliability, [beta], and for different nominal design properties of the pultruded materials. The resistance factors were determined using Monte Carlo simulation based on the results of 75 tests of full-scale pultruded columns that have been reported in the literature. In addition, resistance factors and structural reliabilities were calculated for the design equations provided by the manufactures in their design codes. The paper demonstrates that a unified design equation for pultruded columns can be developed for LRFD with reliability indices that are similar to those used for conventional materials. The paper also shows that markedly different reliability indices are obtained for the different manufacturer-provided equations even though identical allowable stress design safety factors are recommended by all manufacturers. DOI: 10.1061/(ASCE)ST.1943-541X.0000126 CE Database subject headings: Columns; Structural reliability; Buckling; Flanges; Pultrusion; Load and resistance factor design. Author keywords: Columns; Resistance factors; Reliability; Local buckling; Global buckling; Wide flange profiles; Pultrusion.

Construction continues to be a significant part of the global economy and shapes the built environment and quality of life for people around the world. In the United States, construction is a multibillion dollar annual enterprise, employing nearly l0 million people. However, it appears that the fragmented nature of the industry continues to hamper productivity and hoped-for gains in efficiency. Issues involve an array of regulatory and legal constructs that: (1) redistribute risk; (2) present only low barriers to entry (making company startup somewhat easy); and (3) fail to provide the quality and quantity of labor necessary. These factors continue to produce overall inefficiencies throughout the construction industry, and ill prepare the industry for the formidable challenges of globalization, sustainability, population growth, and wise use of resources. The purpose of this paper is to review the past and present of construction engineering within the context of civil engineering, and to prescribe practical change to revitalize construction engineering education to meet future demands. CE Database subject headings: Construction management; Engineering education; Curricula; Information technology (IT).

As buildings have become larger and house more people, political and societal issues have become more complex, and risks associated with occupying buildings have changed. In particular, since the terrorist attacks of 2001, the anxiety levels and perceived risks of building occupants (especially occupants of tall, high-profile buildings) have increased. These perceived risks include risks of terrorist attacks, natural disasters, the possibility of bomb threats, and catastrophic fires. The public's perception of risk is already incorporated into building design codes and performance-based design (PBD) methods for such hazards as earthquakes and fires--explicitly in some cases, implicitly in others. Risk perception will clearly need to be addressed in the design of buildings, as trade-offs in 'acceptable' risk versus cost must be made. As terrorism represents a constantly changing design challenge, and is a target-specific hazard, as opposed to a location-specific hazard, it seems unlikely that prescriptive code requirements will be entirely effective at addressing this hazard. PBD codes are a promising approach for design issues that deal with such 'cutting-edge' concepts. DOI: 10.1061/(ASCE)0887-3828(2007)21:1(61) CE Database subject headings: Building codes; Risk management; Hazards; Earthquakes; Fires; Terrorism.

The Editorial Board of the American Society of Civil Engineers Journal of Composites for Construction (Lawrence C. Bank, Editor) sponsored a survey of the civil/structural engineering programs around the world on the subject of fiber reinforced polymer (FRP) composites, excluding the traditional steel-concrete composite construction and fiber reinforced concrete. This paper summarizes the main results from the survey. During the last decade, considerable focus has been devoted to the use of FRP composites in construction. The main driving force is the need for revitalizing the aging infrastructure with innovative materials and structural systems that last longer and require less maintenance. As the construction industry embraces FRPs in the field, the need for educating civil engineers with background on the subject has become more evident. Despite a significant number of field applications and laboratory research, the survey shows that FRPs have not yet been fully implemented in the engineering curricula, and the classrooms are still lagging behind. To improve this situation, civil engineering and their extension programs must provide sufficient training on unique features of FRPs so that engineers could design or specify them in construction. This survey should be repeated as a gauging tool again at the end of this decade. CE Database subject headings: Engineering education; Fiber reinforced polymers; Construction; Surveys.

The response of a G4(1S) strong post steel w-beam guardrail system to pendulum impacts has been investigated in a series of full-size physical tests and in simulated experiments using the explicit finite-element analysis code DYNA3D. The physical tests were conducted at the Federal Outdoor Impact Laboratory at the Turner Fairbank Highway Research Center of the Federal Highway Administration in McLean, Va. In the pendulum tests, an 880-kg mass was used to strike the rail perpendicular to its face. The rail section was attached to steel posts and blockouts and supported in a specially designed fixture. Initial velocities of the pendulum at impact were 9.25, 20, 30, and 35 km/h. Acceleration, force, velocity, and displacement histories of the impact event were obtained from accelerometer data taken during the testing. Data from the DYNA3D simulations of the impact tests compared well with the data obtained from the full-scale testing. Displacement plots of the deformed shapes of the rails at 25-ms intervals compared favorably with high-speed film images. Force versus displacement histories showed good agreement with those obtained from quasi-static experiments. The use of pendulum impact tests for screening and evaluation of alternative guardrail systems is recommended.

This paper focuses on the conceptual use of a fiber-reinforced polymer (FRP) wind turbine blade that is repurposed for a second life as an electrical transmission pole. Thousands of tons of fiber-reinforced polymer composite wind turbine blades are currently coming out of service globally and are being landfilled or incinerated. These are not environmentally preferable disposal methods. This paper presents a detailed structural analysis of a Clipper C96, 46.7-m-long turbine blade used as an electrical pole. The analytical procedure needed to characterize the wind turbine blade for repurposing includes determining the external and internal geometry of the blade, identifying the types of materials and laminates used throughout the blade, and calculating effective moduli and section properties for structural analysis. Code-specified load combinations are then used to analyze the transmission line BladePole to determine internal forces and deformations and stresses. Maximum stresses were compared to those obtained from theoretical models. The results indicate that wind turbine blades can safely be used as electrical transmission poles. [ABSTRACT FROM AUTHOR]

Results of an experimental and analytical investigation of the behavior of a pultruded fiber-reinforced plastic (FRF) portal frame subjected to short-term static loads are presented. A 6 ft high by 9 ft wide (1.83 m x 2.74 m) plane portal frame was designed and constructed of glass/vinylester pultruded FRP thin-walled sections. Data obtained from short-term load tests on the frame are presented. Failure of the beam-to-column connections and compression flange buckling of the girder are discussed. An analytical investigation was performed to predict the nonlinear response of the frame. The numerical model includes the effects of axial, shear, and flexural deformation of the pultruded numbers, flexibility of the beam-to-column connections, and the postbuckling of the frame girder. An expression for the nonlinear rotational stiffness of the pultruded beam-to-column connection is presented. The experimental data, obtained from the full-size test, are compared with the analytical model., The experimental and theoretical analysis of the short-term response of a full-size pultruded fiber-reinforced plastic portal frame are presented. The linear and nonlinear behavior of the frame including the failure mechanisms are described. Results show that the flexibility of the beam-to-column frame connection determines the frame response. Comparison between experimental and theoretical results also showed good agreement.

The objective of this research is to demonstrate that parts of decommissioned wind turbine blades can be repurposed for infrastructure applications for a sustainable future of the wind power industry. The purpose of this paper was to develop a methodology to conduct detailed structural engineering design of composite material parts extracted from wind turbine blades. A large section extracted from a 100-m long blade was repurposed as a roof for a small (approximately 40 m2) single-story masonry house. Geometric and material properties were taken from the blade design documents. A three-dimensional graphical model was created from the exterior surface and material layups. The roof was designed using the load and resistance factor design method familiar to civil engineers. Analysis of stresses and defections was conducted using hand calculations and the finite element method. The results of the analyses showed that the roof is within code mandated stress and deflection limits. The methodology developed could be applied to other wind blade repurposing concepts. [ABSTRACT FROM AUTHOR]

An evaluation of the hand-calculation method for assesing the behavior of anisotropic composite beams is presented. This method is used in preliminary design studies of anisotropic panel composite materials which are used as structural components of aeropspace vehicles. Results indicate that this method can be used to predict the out-of-plane coupled deformation of transversely loaded composite beams.

Shear failure of reinforced concrete members is brittle and catastrophic, and should be avoided. This work presents a comparative study of concrete beams with natural crushed stone and those incorporating recycled concrete aggregate (RCA). The study indicates that the equation presented in ACI 318-14 Code requirements for predicting the shear strength of concrete is less conservative for RCA concrete beams. The presented experimental investigations show that strengthening with fiber reinforced polymer (FRP) fabrics can be designed so that the shear capacity of the beams with weaker (RCA) concrete is higher than that of the control beams with natural aggregate concrete. The design of the FRP strengthening system and the reasons for the effectiveness of the design are explained. [ABSTRACT FROM AUTHOR]

Architects and engineers need specification guidelines for the use of composite materials in the construction industry. This will ensure that composites can be evaluated as alternatives to conventional construction materials such as concrete and steel. The government, education sector and the industry can consolidate their efforts for the creation of specifications for composite materials. This resulting standard should be based on extensive research, thorough testing and analysis and acceptable design procedures and principles.

For the last three decades, fiber reinforced polymer (FRP) composite materials have been widely used in major engineering industries. Managing FRP waste is becoming an important issue due to the growth in the production of FRP composite materials. In this article, the issue of FRP waste management is discussed and the commonly used methods for the handling of FRP waste are reviewed. One potentially viable use of FRP waste is in the partial replacement of fillers or aggregates in cementitious materials (particularly portland cement mortar and concrete). A number of important prior investigations performed on the use of FRP waste in concrete and mortar are reviewed. The results from most of those investigations suggest that FRP aggregates significantly reduce the strength of cementitious materials with little significant effect on durability. Recommendations for future research in this area are provided for producing stronger mortars and concretes incorporating FRP production and end-of-life waste. [ABSTRACT FROM AUTHOR]

Five 609.5-mm deep fiber-reinforced polymer (FRP) beams with a span-to-depth ratio of were tested in three-point bending with the beam ends constrained to prevent global failure. A concentrated load was applied at midspan either directly to the top flange or through a 101.6 mm wide by 12.7-mm thick FRP bearing plate resting on the top flange. VIC-3D Digital Image Correlation Measurement Software from Correlated Solutions captured out-of-plane displacement of the webs, and Southwell plots were generated to determine buckling loads. Each specimen experienced a stability failure of the web before undergoing material failure in the upper web-flange junction. On average, web buckling occurred at 90% of the ultimate load. The introduction of a bearing plate did not significantly affect the buckling load or ultimate capacity of the specimens. One specimen was tested into the postbuckling range, unloaded, and reloaded to material failure and experienced no loss of strength or stiffness. Another specimen with significant damage to the unloaded web-flange junction was tested and compared with a virgin sample. The damaged sample experienced no significant loss of strength or stiffness. Comparisons of experimental data with three theoretical equations for web-buckling capacity of FRP beams are provided. [ABSTRACT FROM AUTHOR]

Highlights: [•] Failure mode and ultimate capacity of web-strengthened FRP beams subjected to concentrated loads. [•] Eleven beams were tested; three strengthening systems were used. [•] Strengthening systems: doubler plates, bearing stiffeners, and junction stiffeners. [•] All strengthening system increased ultimate capacity of specimens. [•] Only junction stiffeners changed the failure mode of specimens. [Copyright &y& Elsevier]

The purpose of this paper is to provide a review of and observations on progressive failure and ductility of fiber-reinforced polymer (FRP) composites of interest to civil and infrastructure construction applications. The primary reason for this is that although FRP composites have over the last 25 years successfully penetrated niche markets in civil engineering applications, one of the most frequently heard concerns from designers is their discomfort with the ductility of these composites and the structures built or reinforced with them, and that if the market for FRP applications in construction is to be expanded, the community must address this issue in greater depth. One approach is to use systemwide, structural, progressive failure behavior of the composite material itself to dissipate internal strain energy in lieu of the elastoplastic behavior of metallic materials. Specific applications of FRP composites in construction where progressive failure mechanisms have been considered are reviewed. These include FRP profiles, FRP frame connections, FRP reinforcing bars, externally bonded FRP or mechanically fastened FRP strengthening strips, and FRP column wraps. [ABSTRACT FROM AUTHOR]

The use of pultruded fiber reinforced polymer (FRP) grids is being investigated as tensile reinforcement in concrete bridge decks. Three full scale simply supported concrete slabs reinforced with double layer pultruded FRP girds representing long span bridge decks were tested. Punching shear was the critical failure mode. The punching shear capacity was compared to the University of Wisconsin punching shear equation, developed for the grid system on shorter spans by Jacobson (2004), and the punching shear capacity as given by ACI 440 (2006). The Jacobson equation conservatively predicted the capacity for slabs with edge restraint and accurately predicted the punching shear capacity for slabs without edge restraint. The ACI 440 (2006) punching shear equation underestimated the punching shear capacity of the slabs. [ABSTRACT FROM AUTHOR]

This study describes an application of a modified strut-and-tie model (STM) for determining the strength of reinforcement-free bridge decks on concrete wide-flanged girders. The method could also be applied to other short-span restrained concrete slabs. The concept presented for the reinforcement-free bridge deck includes a combination of removing steel reinforcement, using compressive membrane action in the deck by tying girders together, and introducing a polypropylene fiber to control shrinkage cracks. An analysis method for these reinforcement-free decks using a modified STM that considers geometrical nonlinearity is proposed. The model provides a two-dimensional (2-D) axisymmetric representation of the behavior of the reinforcement-free deck, and it is capable of capturing punching and flexural failure. Comparisons to nonlinear finite element method (FEM) analysis results were made to verify the proposed analysis method. A design load appropriate for reinforcement-free bridge decks is proposed. [ABSTRACT FROM AUTHOR]

Results of the behavior of pultruded fiber-reinforced polymer (FRP) I-shaped beams subjected to concentrated loads in the plane of the web are presented. Twenty beams with nominal depths from 152.4 to 304.8 mm were tested in three-point bending with a span-to-depth ratio of four. Load was applied to the top flange directly above the web-12 without bearing plates and 8 with bearing plates of varying width and thickness. All test specimens failed with a wedgelike shear failure at the upper web-flange junction. Finite-element results support experimental findings from strain gauge and digital image correlation data. Bearing plates increased beam capacity by 35% or more as a function of bearing plate width and thickness. Bearing plates increased average shear stress in the web at failure from 17.4 to 27.2 MPa-below the accepted value of in-plane shear strength (69 MPa). A design equation is presented, and predicted capacities are compared with experimental results. The average value of experimental capacity to predicted capacity is 1.12 with a standard deviation of 0.11 and coefficient of variation (COV) of 0.10 for sections up to 304.8 mm deep. [ABSTRACT FROM AUTHOR]

Due to the lack of data and experience with designing buildings for a bioterrorism hazard, it is important for civil engineering professionals to understand both the way that risk is currently accounted for in the design of a building for a bioterrorism hazard and the methods for analyzing risks to buildings that can be borrowed from risk analysis professionals. This paper provides a literature survey of four subject areas dealing with the risk analysis of bioterrorism applied to buildings: (1) perception of the risk of bioterrorism; (2) risk analysis of bioterrorism; (3) risk management of bioterrorism risks; and (4) risk communication of bioterrorism risks, and includes an example of a simple risk analysis process for a hypothetical building. Bioterrorism presents building design engineers with new challenges. It is a very unpredictable hazard, and very little data exist to guide building designers and decision makers in protecting buildings from this hazard. Designing a building with bioterrorist attacks in mind involves many different disciplines, including, for example, structural, mechanical, and electrical engineering, architecture, landscape architecture, security design professions, and law enforcement. Large consequences are possible in the event of a successful attack, and many building design engineers have little or no experience with defending against a bioterrorist attack. It is important that a reasonable process for analyzing and dealing with these risks be established, and that the process include issues of risk perception and communication within the risk analysis framework. [ABSTRACT FROM AUTHOR]

A feasibility study in which the use of a commercially produced pultruded fiber reinforced polymer (FRP) plank for both permanent formwork and secondary or primary tensile reinforcement of a concrete structural member is described in this paper. To achieve satisfactory bond at the interface between the smooth surface of the FRP plank and the concrete, two kinds of aggregate, gravel and sand, were epoxy bonded to the planks. Concrete beams using the aggregate-coated FRP planks were fabricated and tested. Satisfactory bond between the FRP plank and the concrete was developed which was evidenced by numerous well-distributed flexural cracks, and ultimate capacities of the aggregate coated FRP plank specimens greater than the steel rebar reinforced control specimen. ACI 440 equations were found to provide good predictions of the flexural strengths but poor predictions of the shear strengths of the FRP plank reinforced beams. ACI 318 equations, however, provided good shear strength predictions. [ABSTRACT FROM AUTHOR]

This paper presents a case study of prefabricated double-layer pultruded fiber-reinforced polymer (FRP) grids for bridge deck construction. These grids were used to reinforce a 39.6 m long by 13.7 m wide (130 by 45 ft) bridge deck on US Highway 151 over the De Neveu Creek in Wisconsin. The Federal Highway Administration Innovative Bridge Research and Construction Program invested resources in this program to investigate new uses for off-the-shelf technologies in constructing highway bridges. The feasibility of modifying manufacturing techniques to create innovative double-layer, 3D pultruded, FRP grids measuring 12.9 m long by 2.4 m wide by 16.5 cm deep (42 ft6 in. by 8 ft by 6 1/2 in.) was investigated. In addition, the feasibility of placing the grids rapidly and constructing a bridge deck was also demonstrated. The FRP grids were required to meet a prescriptive material specification and a structural performance specification. Shear connectors were designed by the manufacturer to join large top and bottom grids to form an integrated 3D reinforcing module. From a construction perspective, the reinforcement grids were designed to be moved in a single lift of a crane and placed on the bridge girders. The paper reports on the development of the FRP 3D grids and provides details on the construction aspects of the bridge project. [ABSTRACT FROM AUTHOR]

The current method of bonding fiber-reinforced polymer (FRP) strengthening strips to concrete structures requires extensive time and semiskilled labor. An alternative method is to use a commercial off-the-shelf powder-actuated fastening system to attach FRP strips to concrete. A series of flexural tests were conducted on 15 304.8×304.8×3,657.6 mm(12×12×144 in.) reinforced concrete beams. Two beams were tested unstrengthened, 12 were strengthened with mechanically fastened FRP strips, and one was strengthened with a bonded FRP strip. The effects of three different strip moduli, different fastener lengths and layouts, and predrilling were examined. Three of the beams strengthened with mechanically attached FRP strips showed strengthening comparable to the beam strengthened with a bonded FRP strip. The same three beams strengthened with mechanically attached FRP strips also showed a greater ductility than the beam strengthened with a bonded FRP strip. [ABSTRACT FROM AUTHOR]

Progressive tearing failure has been identified as an important damage mechanism in single-cell, thin-walled, rectangular pultruded composite material tubes subjected to transverse (bending) loads. This progressive failure occurs along the corners of the tube at the junction between the cell walls and propagates in a stable fashion as the transverse load is increased. This allows the tube to undergo large global flexural deformation as well as local cell wall deformation needed to develop membrane response before ultimate failure. The response enhances load-carrying capacity in the tube and provides energy absorption during the failure. A numerical method has been developed to model the crack propagation along the corners of the tube using an energy criterion. The energy release rate for the mixed-mode crack propagation corresponding to the progressive tearing failure has been determined for pultruded composite material tubes that were tested in a previously reported experimental study. Effects of different tube configurations, geometries, and end-supports on the energy absorption are reported. It was found that substantial energy can be dissipated by the progressive tearing failure of the tube if appropriate axial restraint is provided at the ends of the tube. [Copyright &y& Elsevier]