大跨度悬索桥主梁抗风试验研究

Research on Wind Resistance Test for Main Beam of Large-span Suspension Bridge

悬索桥跨径越大,结构越轻柔,对风致振动越敏感,因此,研究悬索桥主梁抗风性能尤为重要。对某主跨1196m大跨度悬索桥,采用有限元建模计算分析了成桥状态的结构动力特性;通过静力节段模型试验,测试了成桥状态主梁的三分力系数,结果表明:该扁平加劲梁整体上具有较好的静风稳定性能;通过动力节段模型试验考察了成桥状态桥梁在风攻角为0°、±3°、±5°下的颤振稳定性能,风攻角为+3°和+5°时,颤振临界风速接近或低于颤振检验风速,其余风攻角下颤振稳定性能良好;通过优化人行栏杆构造、增大透风率对主梁断面进行优化,有效改善了主梁断面的气动性能。

The larger the span length of the suspension bridge is, the more flexible the structure is. It is more sensitive to the wind-inducted vibration, so the research on the wind-resistant performance of the main beam of suspension bridge is very important. As for the large-span suspension bridge with a main span of 1196m, the computational analysis on the dynamic characteristics of the structure of finished bridge state is made by adopting the finite element modeling. The mean aerodynamic force coefficient of main beam of finished bridge state is tested by the static section model test. The results show that： the flat stiffening beam has better static wind stability performance on the whole; the stability performance of flutter of the bridge in the finished bridge state under the wind attack angle of 0°, ±3°or ±5° is inspected by the dynamic section model test. When the wind attack angle is ＋3° or ＋5°, the critical wind speed of flutter is close to or lower than the inspection wind speed of flutter, and the stability performance of flutter under the rest wind attack angle is good; the optimization on the section of main beam is made by optimizing the structure of pedestrian guardrail and increasing the ventilation rate, so as to effectively improve the aerodynamic performance of the section of main beam.