Design and performance assessment of a novel self-anchored pedestrian suspension bridge

Conventional suspension bridge systems generally adopt a symmetrical layout, which has limited applicability in asymmetric urban terrain. However, the span capacity of the asymmetric bridge system is not as good as that of the conventional suspension bridge. Therefore, under the constraints of limited space, it is very urgent to design a new asymmetric pedestrian bridge with a strong crossing ability on the complex asymmetric terrain of the city. However, the design faced two challenges. (1) Because of the asymmetry of the structure, the cable balance equation and calculation theory of the new bridge need to be redetermined; (2) Because of the restriction of terrain conditions, it is necessary that optimize the preliminary design of the new bridge to achieve better mechanical properties. To address above problems, a new self-anchored continuous steel box girder composite system is proposed for use in suspension footbridges. This system uses connectors to reliably connect the suspension, main girders, and pylons. The continuous beam structure is used in the side span of the pedestrian bridge and the cable-stayed beam composite system is used in the main span. Therefore, the mechanical behavior of the structure is complex. To investigate the mechanical characteristics of the new structural system based on the preliminary conceptual design, the static and dynamic stability of the proposed structural system is comprehensively analyzed. A new force mode is proposed to improve the mechanical properties of the proposed structural system, and the applicability of the tuned mass damper to the new structural system was verified. Finally, an improved multi-objective genetic algorithm (I-MOGA) algorithm is hired to optimize the layout and mechanical properties of the proposed-composite system. The effectiveness and feasibility of the proposed-composite system bridge is verified to design for urban pedestrian bridges in limited terrain. Moreover, I-MOGA is used to optimize the design of the proposed mixed systems and obtain an improved structural layout for a complex pedestrian bridge in terms of forces, stability, and reliability. This study will provide a reference for the design of urban bridges on asymmetric terrain.