Development of an anchorage prototype for CFRP stress-ribbon systems using 3D printing technique

Compared with other structure types, stress-ribbon systems are extremely simple though requiring massive anchorage blocks because of very large tensile stresses induced in the ribbons. Such structural systems are efficient in pedestrian bridges. A major drawback of these systems is related to corrosion of the steel ribbons. Unidirectional carbon fibre reinforced polymer (CFRP) has a high potential for replacing steel in the ribbons because of lightweight, high strength, and excellent resistance to corrosion and fatigue. Application of CFRP materials, however, faced serious problems due to construction of the anchorage joints. Thus, the anchorage system is the object of this research. Adhesive bonding is a simplest technology for joining structural components made of CFRP composites with polymer matrix. In the adhesion joints, the loads are transferred due to the shear effect. However, a relatively low inter-laminar shear strength of CFRP decreases effectiveness of the gripping systems. Brittle failure of the bond is often consequence of stress concentration. An innovative anchorage joint is proposed to control shear stresses by varying a local curvature of the contact surface. A natural shape of Nautilus shell was chosen for the gripping system, whereas a 3D printing technique was applied for the prototyping purpose. Mechanical behaviour of the anchorage prototypes made of printed polymeric material was investigated experimentally.