【摘要】 位于云南省鲁甸县的牛栏江大桥是三跨一联(90 m+170 m+90 m)的预应力混凝土刚构桥,混凝土薄壁空心墩高度为128 m,是典型的高墩大跨混凝土刚构桥。为了系统研究该类桥梁的抗震性能,对牛栏江大桥实施了模态测试。通过合理选择传感器和记录器,恰当地布置测点,克服了信号弱、频率低、测点间距大等困难,得到了高质量的反映该桥模态的数据。结合数值分析给出了振型形状,依据实测数据得出该桥的竖向、纵向和横向多阶模态。由于该桥构造上具有横向类似悬臂梁的特点,约束最少,相对薄弱,模态结果证实了这一认识。更多还原

【Abstract】 The Niulanjiang Bridge,which is located in Ludian county,Yunnan Province,is a triplet(90 m + 170 m + 90 m)prestressed-concrete rigid frame bridge.The thin-walled hollow concrete piers are 128m high.In order to study the seismic performance of concrete rigid frame bridge with super high piers and long spans,in field modal identification was carried out on the Niulanjiang Bridge.Through reasonable selection of sensors and data loggers as well as appropriate arrangement of measuring points,difficulties of weak signal,low frequency,and large measurement distance were overcome,and high quality data that reflect the bridge’s modes were obtained.With the mode shapes from numerical analysis and the measurement data,multiple modes in vertical,transverse and longitudinal directions of the bridge were determined.Because in configuration the bridge has the least restraints in the transverse direction,with the similar characteristic to that of a cantilever beam,it would be relatively weak in this direction.The mode results confirmed this judgment.These measurement results can be a good reference to designers of this bridge and other similar bridges.更多还原