Buffeting response and mitigation measures of large-span arch bridges during cantilever construction

This study delves into the dynamic behavior of a half-through steel truss arch bridge with a main span of 400 m, with specific focus on its wind-induced buffeting displacement response and various vibration mitigation strategies during the maximum cantilever construction stage. Firstly, a detailed finite element model of the arch bridge structure during the maximum cantilever construction phase is established. Then, the three-dimensional pulsating wind field is simulated using the harmonic synthesis method, and the buffeting displacement response at the cantilever end of the arch rib and the top of the buckle tower is calculated employing the time-domain analysis method. These theoretical findings are compared and validated with the wind tunnel test results. Finally, the effectiveness of various vibration mitigation measures is thoroughly examined. The results show that, installing vertical wind-resistant cables at the arch rib cantilever end can significantly reduce vertical buffeting displacement. Furthermore, installing wind-resistant cables at a 45° angle for both the buckle tower and the arch rib results in vibration reduction rates of 62.5%, 84.8%, 61.0%, and 62.7% for the lateral and vertical displacements of the arch rib, and the lateral and along-bridge buffeting displacements of the tower, respectively. Additionally, a spatial staggered connection and a vertical plane staggered soft connection at the cantilever end of the arch rib can lead to notable vibration reduction effects of 49.5%, 95.7%, and 67.1% for the lateral and vertical displacements of the arch rib, and the along-bridge buffeting displacement of the tower, respectively.