Cyclic Construction and Load Redistribution in Steel–Ultra-High-Performance Concrete Composite Arch Using Optimized Sliding Connectors

Abstract

The proposed steel–ultra-high-performance concrete composite truss (SUCT) arch bridge addresses three major technical problems of conventional arch bridges and extends the span to 600–1000 m. An intelligent cyclic construction method and an automated sliding connector are proposed for the SUCT arch ring to reduce construction costs and mitigate stress superposition. This method involves multiple closures of the arch ring from inside to outside. This paper introduces the cyclic construction method, compares it with existing methods, and investigates the mechanical behavior and load distribution of the arch ring through experimental analysis in both slidable and locked states of the sliding connectors. An optimized design for sliding connectors was also developed. The results indicate that the cyclic construction method offers distinct advantages over traditional techniques, ensuring the construction feasibility of SUCT arch bridges. The sliding connectors released most vertical shear forces, and the corresponding bending moments were transferred to the inner arch. Consequently, approximately 10% of the load was transferred to the inner arch, representing approximately 20% of the load in the locked state. However, approximately 25.5% of the negative bending moments were transferred to the inner arch in spring conditions. During the arch ring’s asymmetric loading process, the inner arch’s left spring cracked and crushed before the outer arch due to stress superposition. By optimizing the sliding surface to a vertical orientation (0°) and lubricating the sliding plate and chute, negative bending moments and vertical loads were effectively isolated from the inner arch, eliminating stress superposition and significantly enhancing crack resistance and load-bearing capacity. With the optimized design, the load borne by the innermost arch was reduced to 48% and 85% compared to the non-sliding connector scheme and the original design. Furthermore, the load distribution across all truss arch rows was uniform. These findings advance both the theoretical understanding and practical implementation of innovative arch bridge construction, offering insights for the infrastructure sector.