针对混凝土结构在太阳辐射和气温变化等环境因素的影响下容易产生不均匀温度分布,从而引起结构静动力性能变化的问题,设计、制作了混凝土板温度效应实验模型,安装多个温度传感器测试结构的温度梯度和环境温度,并测量了一整天的温度变化状况及结构的动力特性.基于模态测试理论开发了模态识别程序包,以识别结构的频率、振型和阻尼比等动力特性参数.实验结果表明,温度对结构的自振频率造成了一定的影响,结构温度升高1℃时引起的第1阶和第2阶频率分别减小0.074和0.228 Hz.
Numerous long-span bridges have been built throughout the world in recent years.These bridges are progressively damaged by continuous usage throughout their long service life.The failure of local structural components is detrimental to the performance of the entire bridge,furthermore,detecting the local abnormality at an early stage is difficult.This paper explores a novel damage detection method for long-span bridges by incorporating stress influence lines(SILs)in control charts,and validates the efficacy of the method through a case study of the Tsing Ma Suspension Bridge.Damage indices based on SILs are subsequently proposed and applied to hypothetical damage scenarios in which one or two critical bridge components are subjected to severe damage.The comparison study suggests that the first-order difference of SIL change is an accurate indicator for location of the damage.To some extent,different levels of damage can be quantified by using SILs incorporating with X-bar control chart.Results of this study indicate that the proposed SIL-based method offers a promising technique for damage detection in long-span bridges.
