中文摘要：

针对运营车辆荷载作用下大跨PC梁桥动挠度特性问题,以琶洲大桥和洛溪大桥为背景工程,采用有限元计算和现场试验获取其车辆荷载动挠度,并分别在时域和频域,重点研究了运营车辆荷载作用下动挠度的统计特征和频谱特性。研究结果表明,模拟车辆荷载作用下的动挠度与实测动挠度吻合较好,两座背景桥的动挠度计算值以及实测值的均值和方差均在3～5mm范围内,均方差在2mm左右,变异系数超过50%,说明在大跨PC梁桥挠度监测时,不能忽略运营车辆荷载作用下桥梁结构挠度的动态效应,应采用动挠度来表征桥梁结构变形。功率谱密度曲线呈多峰分布,幅值谱属双峰分布,幅值谱主要频率集中在结构振动一阶频率及三阶频率附近。研究结果可为桥梁结构动态挠度监测方法研究和挠度成分分离研究,提供科学依据和基础数据。

英文摘要：

In order to find out the dynamic deflection characteristics of large span PC girder bridge un- der vehicle load, the Pazhou bridge and Luoxi bridge being taken as the study objectives, the structural dynamic deflection under vehicle load is obtained through the finite element method and field test, and the statistical and spectral characteristics of dynamic deflection under simulated vehicle load and practical oper- ation vehicle loads in the time domain and frequency domain. Research results show that the dynamic de- flection of the simulated vehicle loads is consistent with practical operation vehicle loads, and the dynamic deflection mean and variance values of two bridges are in the range of 3mm-Smm, the mean square devia- tion is about 2mm, and the variation coefficient is over 50%, which means the deflection dynamic effect of bridge under vehicle loads cannot be neglected, but dynamic deflection should be used to represent bridge structural deformation. The results also show that two background bridges power spectral density curves are multimodal distribution, amplitude spectrums are two peak distribution, and the main frequency are near to the structure first-order vibration frequency and third-order vibration frequency in the amplitude spectrum. The research results could provide a scientific basis and basic data for the research on bridge dynamic displacement monitoring method and the deflection separating.