基于悬挂吊锤的桥梁动挠度测试

目前基于动挠度测试的混凝土梁桥承载力评定方法尚不完善,为了给现役桥梁的实际承载能力准确快速的评定提供科学准确的依据,客观地反映桥梁的实际运营状况,通过理论推导与室内试验相结合的方法研究了基于悬挂吊锤的桥梁动挠度测试。对于梁体激振源的振动频率、振动幅值、吊锤重量及钢丝绳长度4个变量,通过固定其中3个变量不动,改变其中1个变量,对比分析梁体动挠度与吊锤动挠度之间的关系,再与所推导公式对比分析。结果表明:基于悬挂吊锤的桥梁动挠度测试不仅与吊锤的质量、简谐荷载作用的时间有关,还与作用于梁体激振源的振动频率、振动幅值及钢丝绳长度有关。可见研究结果对基于悬挂吊锤的桥梁动挠度测试研究具有一定的实用性,为采用将测量装置置于测点处悬挂的重物下方来测量桥梁结构动挠度的方法提供一定的理论指导。

Test of Bridge Dynamic Deflection Based on Suspended Hammer

Abstract] At present, the method for evaluating the bearing capacity of concrete beam bridges based on dynamic deflection test is not perfect. The method which combines theoretical derivation and indoor experiments researches the bridge dynamic deflection test based on the hanging hammer. This method is used to provide a scientific and accurate basis for the precise and rapid assessment of the actual bearing capacity of the existing bridge and to objectively reflect the actual operating conditions of the bridge. The research proved that changing one of four variables ( beam excitation source vibration frequency, vibration amplitude, hammer weight and wire rope length), could help scientists to compare the dynamic deflection of the beam and the drop hammer. Meanwhile by comparing and analyzing the deduced equation, a conclusion could be made. The conclusion that the bridge dynamic deflection test based on the suspended pendant is not only related to the quality of hammer but also the time of the simple harmonic load. In the meantime, it also related to the vibration frequency, vibration amplitude and the wire rope length. So it is obvious that the bridge dynamic deflection test research based on the hanging hammer has a certain practicability. It can provide some theoretical guidance to the method of measuring the dynamic deflection of the bridge structure where the measuring devices are placed under the weight suspended at the measuring point.