弹性支承简跨预制预应力混凝土桥的动力试验

THE EFFECTS OF GEOGRID ON REDUCTION OF REFLECTION CRACKING IN ASPHALT OVERLAY

对某高速公路高架桥进行了动力试验,利用偏心质量激振器对桥施加激振,从而获得了振型、固有频率和阻尼比等动力参数。试验得到的两种主要模态振型是第一垂直模态和第一纵向模态。得到的平均阻尼比在预应力混凝土阻尼比的范围内,即平均值为2.12%,在2%~3%内。试验结果与利用SAP 2000忽略地基建立的三维有限元模型计算结果吻合较好。固有频率与试验结果的偏差为8.50%。从测量数据来看,弹性支承有效地降低了从上到下结构的加速度54.62%和60.22%。

The dynamic test of an elevated freeway bridge in Surabaya has been conducted.Eccentric mass shaker succeeded to apply an excitement to the bridge and hence the dynamic parameters such as the mode shape,the natural frequency and the damping ratio were obtained.The two main mode shapes from the test were the first vertical mode and the first longitudinal mode.The average damping ratio attained is within the range of damping ratio of prestressed concrete where the average is 2.12%whereas the range is between 2%~3%.The test results are closely represented by a 3D finite element model using SAP2000 without modelling the whole foundation.The deviation of the natural frequency compared to the test results is 8.50%.The elastomeric bearing effectively reduces the acceleration from upper to the bottom structure by 54.62%and 60.22%obtained from two measurements.