An innovative frictional anchorage system for flat CFRP ribbon strips

Abstract

Unidirectional carbon fibre-reinforced polymer (CFRP) materials represent a promising alternative to steel because of their lightweight, high tensile strength, and excellent corrosion and fatigue resistance. Stress-ribbon structural systems define the potential application object of unidirectional flat CFRP strips. However, anchorage difficulties make this idea problematic—the typical gripping systems are inefficient for anchoring the CFRP ribbons because of the tremendous thrust forces-induced stress concentration. Thus, the innovative frictional spiral anchorage system of the flat CFRP strips is the object of this study, which formulates the design principles for the frictional joins. Furthermore, the proposed theoretical model minimises the gripping system size, satisfying the CFRP strength limitation when the developed modified Archimedean spiral determines the shape of the contact surface. This work experimentally demonstrates the theoretical concept’s adequacy—the mechanical resistance prediction error does not exceed 7% in the loading range covering the service load conditions. In addition, the manuscript presents several examples of frictional gripping systems, including the stress-ribbon pedestrian bridge prototype, and provides further insights into the frictional anchorage systems.