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An arch glass fiber reinforced polymer (GFRP) I-beam with a 600 mm height was developed based on the latest curved-pultrusion technique to overcome the most critical design issues of large-scale GFRP beams, including excessive deflections and premature buckling failures. To achieve this goal, a review was first conducted regarding the complex buckling behaviors of pultruded GFRP beams, building a theoretical basis for the development of the curved beam. Then, a series of three-point bending tests for beams were conducted at full scale, in which the typical failure modes, load-carrying capacities and deflection and strain data were obtained. Compression flange delamination was found to be the dominant failure mode. The load–strain curves for flange and web plates demonstrated that the proposed beams were exempt from local buckling issues. Additionally, an analytical study and finite element modeling were carried out. Excellent agreement between experimental, analytical and numerical studies was observed. The design approach for conventional straight profiles is readily applicable to curved beams as the difference is limited. In the end, a 20-m-long full-scale GFRP pedestrian bridge was designed, constructed and tested. The great potential of the proposed curved-pultruded GFRP arch beam was successfully demonstrated.

As a pivotal anti-corrosion structure in the wet flue gas desulfurization system, the huge filament-wound GFRP (glass fiber-reinforced polymer) tube is often employed as the chimney liner. However, the study on its mechanical properties is rare. Three large-scale stiffened cylindrical GFRP chimney liner segments were tested under the axial compression, including an integrated filament-wound chimney liner specimen with two ring stiffeners, a specimen with two ring stiffeners cut into two segments and joined by a hand-wound technique, and a specimen with an outside ring bracket. The failure modes, load-displacement relationships, variation of strains during the loading process, were acquired by test. The effects of ring stiffeners on the mechanical behavior, service reliability of the joint between the two segments of the chimney liner, and the reliability of the ring bracket were examined. Comparisons between theoretically calculated stiffness and experimentally measured stiffness were discussed. Finally, finite element analysis was performed to examine the failure modes and axial load-displacement behavior of the investigated chimney liners. Different ranges of diameter to thickness ratios and load eccentricity values were selected to examine their effects on the mechanical behavior of chimney liners. Finally, suggestions on the design of chimney liner structure were given.

A method to improve the mechanical behavior of 3D-printed elements is presented. 3D-printed elements are orthotropic and weak in their interlayers; thus, FRPs, which are easy-formed, light-weighted and high-strength, are ideal materials to enhance 3D-printed elements. To investigate the reinforcement effect, uniaxial compression tests were conducted on circular column specimens, and four-point flexural tests were conducted on beam specimens. The results indicated that wrapping 3D-printed columns with FRPs changed their failure modes from brittle to ductile, increased the peak loads that they could endure by 1427.2–1792.0% and increased the largest deformations they could achieve by 833.9–1171.3% using different numbers of layers and types of reinforcement. For the 3D-printed beams reinforced with FRPs, the bearing capacities were increased by 179.6–604.5%, and their flexure deflections at their mid-spans were increased by 40.8–225.8%. The failure modes of the 3D-printed beams were affected by numbers of layers and types of reinforcement. Additionally, finite element analyses were conducted to simulate the failure modes of the 3D-printed elements based on the maximum stress criterion. The results showed that the predicted failure locations corresponded with the experimental failure locations observed. According to this study, 3D-printed elements reinforced with FRP sheets showed potential for future development and applications in construction.