Effect of CFRP tendon-strut system on the bearing performance of GFRP-aluminum space trusses

The low longitudinal elastic modulus of glass fiber-reinforced polymer (GFRP) material compared to that of steel material may lead to insufficient overall stiffness of its assembled space truss structure and stability problem of truss member. Inspired by steel beam string structure, prestressed carbon fiber-reinforced polymer (CFRP) tendon-strut systems were proposed and incorporated into the GFRP-aluminum space trusses to achieve enhancement of structural performance with less increase in structural weight. The effects of two types of tendon-strut systems on the bearing performance of the space trusses were investigated through three-point bending tests, and were compared with a control truss without tendon-strut system. The full-process mechanical response of all structural specimens during the elastic and nonlinear phases was analyzed and revealed, with the aid of fine line elements FE models. Furthermore, parametric analyses were carried out based on the verified FE models, including prestress level and diameter of CFRP tendons, as well as the rise-to-span ratio and sag-to-span ratio of the structure, on the ultimate load bearing performance of the prestressed structures. The results demonstrated that prestressing can significantly improve the bearing performance of the space trusses, and a series of design recommendations were proposed for this novel structure form.