环境条件影响下悬索桥模态频率变异性的定量评价

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振动与冲击 ›› 2011, Vol. 30 ›› Issue (8) : 230-236.

论文

环境条件影响下悬索桥模态频率变异性的定量评价

邓扬; 丁幼亮; 李爱群

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Quantitative evaluation of variability in modal frequencies of a suspension bridge under environmental conditions

Deng Yang; Ding You-liang ; Li Ai-qun

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摘要

本文基于长期监测数据，研究了由环境温度、风、交通荷载和识别算法所引起的悬索桥模态频率识别的变异性。首先，采用多样本平均方法建立了温度-频率的季节相关性，减小了频率由识别算法导致的随机误差。其次，将模态频率归一化至某一参考温度以消除温度对频率的影响。通过分析小风速状态下温度归一化频率和加速度响应均方根的相关性，对交通荷载引起的频率变异性进行了定量评价，在此基础上采用交通荷载-频率相关性模型消除了交通荷载对频率的影响，最后定量评价了风速对模态频率的影响。分析结果表明：本文提出的方法可以给出大跨桥梁结构模态频率识别的变异性的量化评价，但目前模态频率的识别方法仍需进一步改进。

Abstract

This paper investigates the measured variability in modal frequencies of a suspension bridge induced by temperature, wind, traffic loadings and identification algorithm simultaneously making use of long-term monitoring data. First the seasonal temperature-frequency correlation is formulated using multi-sample averaging technique to reduce the random variations rising from the identification algorithm. Then the effect of temperature on the measured modal frequencies is eliminated by normalizing these modal frequencies to a reference temperature. The traffic-induced modal variability is further quantitatively evaluated under weak wind conditions by correlation the normalized modal frequencies with the root mean square (RMS) of acceleration responses. Based on the traffic-frequency correlation models, the effect of traffic loadings on the modal frequencies is eliminated and the wind-induced modal variability is quantitatively evaluated. The results indicates that the technique proposed in this study can effectively give a quantitative evaluation of measured variability in modal frequencies of long-span bridges and however at present it still needs to improve the identification algorithm of the modal frequency.

导出引用

邓扬;丁幼亮;李爱群. 环境条件影响下悬索桥模态频率变异性的定量评价[J]. 振动与冲击, 2011, 30(8): 230-236

Deng Yang;Ding You-liang;Li Ai-qun. Quantitative evaluation of variability in modal frequencies of a suspension bridge under environmental conditions[J]. Journal of Vibration and Shock, 2011, 30(8): 230-236