预应力混凝土连续梁桥振动特性变异及舒适度评价

由于预应力损失、混凝土收缩徐变、超载等原因,预应力混凝土桥梁出现了较强的振动。本文通过对福建省福州市闽江三桥全桥环境振动试验和正常运营条件下24小时的监测,研究预应力混凝土连续梁桥的动力特性及其变异和振动舒适度,结果表明:在较为稳定的风和温湿度环境下,固有频率在一天内的最大变化为3.06%,模态阻尼比的最大变化为37.93%,舒适度的狄克曼指标降到“能忍受短时间振动”的区域。

Variability in dynamic characteristics and comfort evaluation of a prestressed concrete continuous girder bridge

The obvious vibration occurred in the prestressed concrete bridge due to the loss of pretresses,concrete shrinkage and creep,and overloading et al.In this paper,the field ambient vibration tests on the No.3 Bridge over Minjiang River in Fuzhou,Fujian Province,were conducted and the vibration during 24h was monitored under normal traffic conditions.The dynamic characteristics and their variability,as well as the comfort of the bridge during vibrations were investigated.The results indicate that the maximum change of natural frequencies can exhibit as much as 3.06% within a day,and that of the damping ratios can reach as much as 37.93% in the relatively steady wind,temperature,and humidity environment.The Dickeeman index of comfort was dropped into the area where the vibration can be suffered only in very short time.