Evolution of suspension bridge structural systems, design theories, and shape-finding methods: A literature survey

Modern suspension bridges exhibit a trend of lighter structures, more diversified structural forms, and longer spans, the latter already exceeding two kilometers. Bridge performance under dead and live loads depends on their structural and main cable systems, while cable-supported bridges especially rely on the design analysis and construction control of the main cable. This literary survey systematically analyzes the research progress and state-of-the-art status quo in the structural systems and design theories of suspension bridges, focusing on the structural systems, main cable shape analyses, live load effect analyses, and emerging lucrative research directions. More than 100 reliable references have been surveyed. (1) Multi-span or multi-main cable schemes appeal to increasing attention, which may become a better choice in terms of structural systems in scenarios with extremely long spans and heavy loads. The cable layouts, such as spatial main cables and hybrid cable-stayed suspension systems have also become feasible approaches for enhancing structural stiffness. (2) The shape-finding analysis during the construction phase is more complex and has more essential factors than that of the completed bridge state. Refined theories combining analytical methods and finite element methods are more suitable for the shape-finding analysis of complex cable systems than any single theory of the two, especially for novel cable systems. (3) The live load effect analysis methods based on traditional deflection theory or modified/improved deflection theories still have wide applications, but the refined theory of treating hangers as discrete members is also constantly developing, which is expected to provide new ideas for more complex structural analysis under the different types of live loads and their distribution forms.