Mechanical performance and design of aluminium alloy beam string structures

Aluminium alloys are widely used in spatial structures because of their lightweight, high-strength, and favourable corrosion resistance characteristics. However, the low elastic modulus of this material results in reduced structural stability compared to that of other construction materials. Therefore, this study proposes incorporating prestress into aluminium alloy structures to improve their structural performance. In this study, two types of aluminium alloy beam string structures (ABSS) are presented along with their corresponding joints. Through static tests conducted on various ABSS joint configurations, this study assesses the in-plane bearing capacity and failure modes of the structures, revealing the mechanism by which prestressing enhances the in-plane performance of aluminium alloy beams. Specifically, this study investigates the influence mechanisms of various factors, such as the rise-span ratio, sag-span ratio, and initial cable force, on the in-plane bearing performance of an ABSS through numerical simulations. Finally, a method calculating the ultimate bearing capacity of aluminium alloy beam string structures is derived by employing the Ritz method, accompanied by design recommendations. The results demonstrate that introducing a prestress can significantly increase the load-bearing capacity by 5-6 times, and the flange-connected joint is determined as more suitable for being implemented in ABSS.