Wind resistance of continuous half-through flying swallow type of steel truss arch bridge

Steel truss arch bridge has the advantages of lightweight components, ease of processing, high load-bearing capacity, and convenient transportation and installation. As a result, they have been widely used in highway and railroad design. In this study, the wind resistance of large span continuous steel truss arch bridges was investigated to guide the construction of such bridges. The main bridge of Muping Xiangjiang Special Bridge in Changsha was used to obtain the wind resistance of the bridge structure and test the wind stability of the bridge through wind environment analysis at the bridge site, structural dynamic characteristics simulation analysis, and wind tunnel testing. Wind tunnel tests were conducted on the mid-span arch ribs, main girders. The side span trusses to obtain the three-component force coefficient for wind attack angles ranged from − 12° to +14°. The results can provide a basis for determining the wind load values of the bridge. Additionally, the test results show that the slope of the lift coefficients of the main girder and side span sections are positive, indicating that these components would not experience vibration. Moreover, segmental model elastic suspension tests are performed to obtain the vertical and torsional displacements of the main girder structure under wind attack angles of −3°, 0°, and 3° during the bridge formation stage and the construction maximum double cantilever condition. The results show that, even when the wind speed of the real bridge reached 100 m/s, far higher than its chattering test wind speed, no chattering occurred in the main girder. This indicates that the bridge has sufficient chattering stability during the bridge formation state and construction process. Furthermore, in the bridge state or the maximum single/double cantilever state, no significant eddy vibration phenomenon is observed in all wind attack angle cases, and the design reference wind speed of the bridge deck is determined to be 34.8 m/s. © 2024, Central South University Press. All rights reserved.