以一座墩塔梁固结体系的独塔预应力混凝土斜拉宽桥——福建泉州晋江大桥为对象,根据实桥环境脉动试验和空间杆系有限元模型进行了主梁-主塔基本动力性能分析;采用振动法进行了斜拉索的固有频率和索力测试,并进行了拉索安全性能评价;根据实桥车辆强迫振动试验和考虑了路面平整度的桥梁与车辆相互作用的计算模型,分析了在移动车辆荷载作用下桥梁的动力特性,包括振动加速度计算和舒适性评价。研究结果表明,采用墩塔梁固结体系的晋江大桥面内振动频率较高,主跨或边跨均出现相互独立或影响较小的振动模态;斜拉索索力分布均匀,安全系数符合规范规定;在移动车辆荷载作用下,主梁竖向振动加速度较小,在设计行车速度下可保持较好的行车舒适性。
Based on the field ambient vibration test and spatial finite element model,the natural dynamic behaviors of deck-pylon was investigated for Jinjiang Bridge in Quanzhou,which is a one-pylon PC cable-stayed bridge with wide deck and rigid fixity of the pylon,girder and pier.The natural frequencies and cable forces of the stay cables were obtained by vibration method,and the safety of stay cables was also assessed.The dynamic property of this bridge subjected to moving vehicles was then studied according to vehicle-forced vibration test and the finite element model considering actual road roughness and the interaction between bridge and vehicle,including the vibration acceleration calculation and the riding comfort evaluation.The results show that(1) Jinjiang Bridge exhibits a higher in-plane natural frequency accompanied by some modes in which one of the two spans has independent vibrations from the other one;(2) the cable forces are uniformly distributed in stay cables and the safety factors can meet the specification requirement;(3) the riding comfort under the moving vehicle loads at the designed traveling speed is satisfying due to the small vertical accelerations.