Design of Main Bridge of Nanpuxi River Bridge and Mechanical Property Analysis

The main bridge of Nanpuxi River Bridge is a deck-type concrete-filled steel tubular arch bridge with a calculated arch span length of 258 m. With a rise-to-span ratio of 1/4. 6, the arch axis follows a catenarian curve, where the arch axis coefficient reaches 1. 6. The arch ring consists of two truss arch ribs formed of concrete-filled steel tubes, and each arch rib is of a four-leg, dumb-bell-shaped constant cross-section, aiming to reduce the horizontal connection tubes in the trusses and facilitate the welding of the truss nodes. The steel tubes and batten plates are filled with C50 self-compacting concrete to supplement the shrunk concrete, as a result, the load bearing capacity and out-of-plane stability of the arch ribs have been improved. The deck system consists of steel 1 girders and concrete slabs, with the intent of reducing the self-weight of the superstructure and maximizing the utilization of prefabricated components. To address the topographical and geological conditions, the skewbacks are situated in the integral moderately-decomposed rocks. The static and dynamic properties of the bridge at the construction and service stages were numerically simulated. The results show that the load bearing capacity of the bridge structure meets the code requirements, proving the effectiveness of the design. © 2023 Wuhan Bridge Research Institute. All rights reserved.