A Split-Wedge Anchorage for CFRP Cables: Numerical Model vs. Experimental Results

Abstract

Fiber-reinforced polymers (FRPs) are widely used within civil structural applications either for structural retrofitting or new constructions. This is due to their appreciable mechanical properties such as high stiffness and strength, resistance to environmental effects, as well low density. Through the years, such peculiarities have encouraged researchers to apply FRP cables within the design of prestressing systems, where steel cables are systematically adopted. However, the brittleness intrinsic to FRP materials necessitates additional efforts to design the anchorage devices. In fact, tendons are here subjected to stress peaks, which need to be controlled in order to prevent the premature failure of the cable. Following this goal, authors recently studied an optimized split-wedge anchorage, for 12 mm-diameter pultruded-carbon-fiber-reinforced polymer (PCFRP) tendons, adopting double-angle (DA) wedges, and compared its performance with a single-angle (SA) wedge configuration. Tensile tests were performed on 3 SA and 2 DA prototypes, respectively, through a universal testing machine: the DA configuration exploited the average cable capacity (257 kN) once, denoting a maximum efficiency. The obtained experimental results are utilized, in the framework of the present work, to calibrate contact parameters of nonlinear finite element models. The presented numerical results helped to assess benefits of the proposed configurations and the behavior of the anchorage components: the DA configuration turned out to satisfactorily avoid stress peak superpositions on the cable, with a reduction in pressure in the loading end of the cable with respect to the SA model.

Design and Validation of a Fiber-Reinforced Polymer Cable-Stayed Pedestrian Bridge: Human-Induced Actions vs. Comfort Levels

“…The proposed site for the bridge is situated within the University of Salerno (Italy) campus. The bridge ( Figure 8 and Figure 9 ) incorporates the following components: (1) PCFRP cables ( ), fastened by split wedge anchorages [ 37 , 38 ]; (2) GFRP sandwiches decks ( Figure 8 b,c), comprising an intermediate system with a) pairs of U-shaped longitudinal ( Figure 8 d) and diagonal/transversal elements ( Figure 8 e) whose material has undergone experimental and numerical studies as documented in [ 39 , 40 , 41 ]; (b) top and bottom panels ( Figure 8 f) (3) pylons ( Figure 9 a) assembled through a) four vertical Double Web Beam ( Figure 9 b); (b) U-shaped with the section geometry reported in Figure 9 c. The mechanical properties of the adopted materials are detailed in Table 10 . One of the primary design goals was to limit the deck acceleration resulting from pedestrian actions.…”

Nonlinear Coupled Vibration Behavior of BFRP Cables on Long-Span Cable-Stayed Bridges under Parametric Excitation

“…In Table 1, the natural frequency (ω) of the stayed cable can be derived based on the theoretical formula for string vibration, as shown in Equation (6). Meanwhile, the experimental results of the damping ratios of the steel cable and the BFRP cable were adopted in this analysis [25].…”

“…As shown in Figure 3, the girder of the Sutong Bridge is the steel box beam made of Q345 and Q370 grade steel, whose sectional parameters are listed in Table 1. In Table 1, the natural frequency (ω) of the stayed cable can be derived based on the theoretical formula for string vibration, as shown in Equation (6). Meanwhile, the experimental results of the damping ratios of the steel cable and the BFRP cable were adopted in this analysis [25].…”

“…Taking mechanical properties and economic performance into consideration, the feasibility of the other FRP materials used to manufacture FRP cables has been studied. Compared with the other FRP materials, basalt fiber-reinforced polymer (BFRP for short) has shown its mechanical and economic advantages, such as high strength, significant elongation, good fatigue resistance, superior anti-corrosion property, good chemical stability, and low cost [6]. With no emissions of harmful gases during manufacture, the BFRP cable has been regarded as one of the green inorganic fiber materials.…”