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Moveable bridges in Florida typically use open steel grid decks due to the weight limitations. However, these decks present rideability, environmental, and maintenance problems, for 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 that are commonly used in moveable bridges with a low-profile FRP deck can improve rider safety and reduce maintenance costs, while satisfying the strict weight requirement for such bridges. The performance of the new deck system, which includes fatigue and failure tests were performed on full-size panels in a two-span configuration. The deck has successfully passed the preliminary strength and fatigue tests per AASHTO requirements. It has also demonstrated that it can be quickly installed and that its top plate bonds well with the wear surface. The thesis also describes the analytical investigation of a simplified finite element approach to simulate the load-deformation behavior of the deck system for both configurations. The finite element model may be used as a future design tool for similar deck systems. Loadings that were consistent with the actual experimental loadings were applied on the decks and the stresses, strains, and the displacements were monitored and studied. The results from the finite element model showed good correlation with the deflection and strain values measured during the experiments. A significant portion of the deck deflection under the prescribed loads is induced by vertical shear. This thesis presents the results from the experiments, descriptions of the finite element model and the comparison of the experimental results with the results from the analysis of the model.

In recent earthquakes, structures have not performed as well as expected resulting in a need for better means of retrofitting and improvements in seismic design. Fiber Reinforced Polymers (FRP), as a material with potential to increase strength and ductility of columns in conjunction with capacity design methodology, has promise for seismic design. By investigating the displacement, ductility, and flexural strength properties of FRP confined reinforced concrete circular cross sections, this study analyzes the seismic applications of FRP confinement. The study is performed by incorporating an FRP confined concrete stress-strain model into a developed Moment-Curvature and PM Interaction software. This software conducts a comparison between traditional steel and FRP confined sections while performing parameter studies on the 28-day unconfined concrete compressive strength, longitudinal reinforcing ratio, cross section diameter, FRP confinement jacket thickness-cross section diameter ratio, and FRP confinement system design variables. These studies validate FRP’s performance for seismic applications resulting in several design recommendations to increase displacement capacity, ductility, and flexural strength and, thus, seismic performance.

Although fiberglass reinforced polyester manholes and wetwalls have been proven by the American Society for Testing Materials (ASTM) and are currently being used in some parts of the world, there still exists a lack of investigation for testing manhole covers made with different inorganic fillers under static and dynamic behavior. The filler would not only improve the mechanical properties of fiber-reinforced polymer matrix composite not otherwise achieved by the resin ingredients alone but also lower the overall manufacturing costs by decreasing the amount of fiber content without adversely affecting the composite’s mechanical properties. The main objective involved the development of fiberglass laminated manhole covers with different inorganic fillers and to study the static and dynamic behavior of the material by performing experimental and numerical analysis. The materials used for the composite laminated test specimens consisted of E-glass woven roving fabric, epoxy, and filler. Two types of inorganic fillers were used for this study, calcium carbonate and high-density adhesive fillers. The static/dynamic test results showed that the laminates made with fiberglass and filler experienced lower performance in tensile strength but higher improvement in flexural strength. The modal analysis results showed that laminates with less filler experienced higher modes within the specified frequency range. This was expected since the material property of filler increased the stiffness and damping behavior in the composite material.

Yes / This paper presents test results of fifteen reinforced engineered cementitious composite (ECC)-concrete beams. The main parameters investigated were the amount and type of reinforcement, and ECC thickness. All reinforced ECC-concrete composite beams tested were classified into four groups according to the amount and type of main longitudinal reinforcement used; three groups were reinforced with FRP, steel and hybrid FRP/steel bars, respectively, having similar tensile capacity, whereas the fourth group had a larger amount of only FRP reinforcement. In each group, four height replacement ratios of ECC to concrete were studied. The test results showed that the moment capacity and stiffness of concrete beams are improved and the crack width can be well controlled when a concrete layer in the tension zone is replaced with an ECC layer of the same thickness. However, the improvement level of ECC-concrete composite beams was controlled by the type and amount of reinforcement used. Based on the simplified constitutive relationships of materials and plane section assumption, three failure modes and their discriminate formulas are developed. Furthermore, simplified formulas for moment capacity calculations are proposed, predicting good agreement with experimental results. / National Natural Science Foundation of China (51678514, 51308490), the Natural Science Foundation of Jiangsu Province, China (BK20130450), Six Talent Peaks Project of Jiangsu Province (JZ-038, 2016), Graduate Practice Innovation Project of Jiangsu Province (SJCX17-0625), the Jiangsu Government Scholarship for Overseas Studies and Top-level Talents Support Project of Yangzhou University.

Externally bonded FRP U-wraps are a common shear strengthening configuration for RC beams, however premature debonding of the wraps is a major problem, which limits the effectiveness and efficiency of the FRP strengthening. In this investigation a new π-shape carbon anchor was used to fasten the FRP U-wraps to the concrete in an attempt to prevent/delay debonding of the wraps and increase their effectiveness. Fourteen large scale rectangular beams with a 1900 mm span, 400 mm height, and 170 mm width were tested in three-point bending with various configurations of FRP shear strengthening. Shear pre-cracks were introduced in the beams at angles of 30 and 45 degrees in an attempt to control the inclination angle of the shear crack and determine its effect on the FRP shear resistance. The FRP shear strengthening configurations included un-anchored U-wraps, U-wraps with anchors, U-wraps with horizontal strips, and full wraps. The results showed that the use of a variable shear crack inclination angle in the CSA S806-12 (2012) standard led to overestimated shear resistance predictions for beams with a single shear crack, therefore a conservative 45 degree shear crack inclination is recommended for design. The use of the proposed carbon anchors resulted in a 74% increase in shear strength over the un-anchored U-wrapped beams, while only using half the amount of FRP. The use of the anchors also resulted in a 286% increase in the ultimate FRP strain over the un-anchored U-wraps, and allowed the FRP wraps to achieve 58% of their rupture strain. The use of horizontal strips provided similar results to the anchors and may be used as a less labour intensive alternative, but this issue needs further investigation. / Dissertation / Master of Applied Science (MASc) / Damaged or older reinforced concrete structures can be rehabilitated by using externally bonded fibre-reinforced polymer (FRP) sheets, which are bonded to the concrete surface using an epoxy adhesive. For the case of shear strengthening of beams, it is common for FRP sheets to be wrapped around the sides and bottom of the beam, resembling a U-shape. The problem with this configuration is that under high levels of load the FRP sheets tend to peel off the concrete surface (debonding). This limits the effectiveness of the rehabilitation and results in the inefficient use of the FRP. A new method for anchoring the FRP sheets to the concrete surface is investigated in this research study. The use of a new in-situ π-shape anchor shows promising results, as it delays debonding and provides a large increase in strength with less FRP needed.

Fiber-reinforced polymer (FRP) composite materials have effectively been used in numerous reinforced concrete civil infrastructure strengthening projects. Although a significant body of knowledge has been established for epoxy matrix carbon FRPs and epoxy adhesives, there is still a need to investigate other matrices and adhesive types. One such matrix/adhesive type yet to be heavily researched for infrastructure application is polyurethane. This thesis investigates use of polyurethane matrix carbon fiber composites for strengthening reinforced concrete civil infrastructure. Investigations on mirco- and macro-mechanical composite performance, strengthened member flexural performance, and bond durability under environmental conditioning will be presented. Results indicate that polyurethane carbon composites could potentially be a viable option for strengthening concrete structures.

The United States of America's Military, more specifically the Army, has since the late 1990's had a vested interest in the development of super-lightweight, portable, short-span composite bridge and decking components to replace aging heavy metal-alloy machine driven modular systems. The following study looks at the feasibility of using balsa wood as the structural core material in fiber reinforced polymer (FRP) wrapped hollow-core composites in short-span bridge applications. The balsa provides shear resistance and the FRP the flexural resistance, resulting in extremely high strength-to-weight and strength-to-depth ratios. Several scaled short span specimens were constructed and tested using a variety of fibers and resins. In addition, a calibrated finite element model (FEM) was developed using data acquired through testing. Of the 3 FRP-matrices tested (carbon-polyurethane, glass-polyurethane, and carbon-epoxy-resin), the carbon-epoxy-resin had the stiffest cross-section and highest ultimate load achieved, although the fiber did not have the highest elastic modulus and ultimate rupture strength of the constituent materials. The carbon-polyurethane fiber had the largest elastic modulus and ultimate strength, but due to construction difficulties did not perform as well as expected. The glass-polyurethane fiber had the lowest elastic modulus and ultimate load with high strain values and performed accordingly during specimen testing. Given the constraints of self-weight, section geometry, and deflection set forth for lightweight short-span portable bridging solutions, this study demonstrates that the balsa-FRP composite systems are viable solutions; in particular, when carbon fabric is paired with balsa cores.

yes / Shear failure of concrete elements reinforced with Fiber Reinforced Polymer (FRP) bars is generally brittle, requiring accurate predictions to avoid it. In the last decade, a variety of artificial intelligence based approaches have been successfully applied to predict the shear capacity of FRP Reinforced Concrete (FRP-RC). In this paper, a new approach, namely, biogeography-based programming (BBP) is introduced for predicting the shear capacity of FRP-RC beams based on test results available in the literature. The performance of the BBP model is compared with several shear design equations, two previously developed artificial intelligence models and experimental results. It was found that the proposed model provides the most accurate results in calculating the shear capacity of FRP-RC beams among the considered shear capacity models. The proposed BBP model can also correctly predict the trend of different influencing variables on the shear capacity of FRP-RC beams.