The fatigue of concrete structures will gradually appear after being subjected to alternating loads for a long time,and the accidents caused by fatigue failure of bridge structures also appear from time to time.Aiming...The fatigue of concrete structures will gradually appear after being subjected to alternating loads for a long time,and the accidents caused by fatigue failure of bridge structures also appear from time to time.Aiming at the problem of degradation of long-span continuous rigid frame bridges due to fatigue and environmental effects,this paper suggests a method to analyze the fatigue degradation mechanism of this type of bridge,which combines long-term in-site monitoring data collected by the health monitoring system(HMS)and fatigue theory.In the paper,the authors mainly carry out the research work in the following aspects:First of all,a long-span continuous rigid frame bridge installed with HMS is used as an example,and a large amount of health monitoring data have been acquired,which can provide efficient information for fatigue in terms of equivalent stress range and cumulative number of stress cycles;next,for calculating the cumulative fatigue damage of the bridge structure,fatigue stress spectrum got by rain flow counting method,S-N curves and damage criteria are used for fatigue damage analysis.Moreover,it was considered a linear accumulation damage through the Palmgren-Miner rule for the counting of stress cycles.The health monitoring data are adopted to obtain fatigue stress data and the rain flow counting method is used to count the amplitude varying fatigue stress.The proposed fatigue reliability approach in the paper can estimate the fatigue damage degree and its evolution law of bridge structures well,and also can help bridge engineers do the assessment of future service duration.展开更多
对圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)系泊锚链的面外弯曲(Out-of-Plane Bending,OPB)问题进行深入分析,对OPB发生风险和可能导致的疲劳损伤进行详细计算。分析结果显示,圆筒型FPSO系泊系统存...对圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)系泊锚链的面外弯曲(Out-of-Plane Bending,OPB)问题进行深入分析,对OPB发生风险和可能导致的疲劳损伤进行详细计算。分析结果显示,圆筒型FPSO系泊系统存在OPB影响,第一个自由链环是整个系泊系统中最关键和脆弱的环节。计算结果表明,系泊锚链的疲劳寿命为43.7 a,满足系泊系统的可靠性需求。研究提出的评估方法可为后续类似工程提供参考,对提高FPSO的可靠性与安全性具有参考意义。展开更多
文摘The fatigue of concrete structures will gradually appear after being subjected to alternating loads for a long time,and the accidents caused by fatigue failure of bridge structures also appear from time to time.Aiming at the problem of degradation of long-span continuous rigid frame bridges due to fatigue and environmental effects,this paper suggests a method to analyze the fatigue degradation mechanism of this type of bridge,which combines long-term in-site monitoring data collected by the health monitoring system(HMS)and fatigue theory.In the paper,the authors mainly carry out the research work in the following aspects:First of all,a long-span continuous rigid frame bridge installed with HMS is used as an example,and a large amount of health monitoring data have been acquired,which can provide efficient information for fatigue in terms of equivalent stress range and cumulative number of stress cycles;next,for calculating the cumulative fatigue damage of the bridge structure,fatigue stress spectrum got by rain flow counting method,S-N curves and damage criteria are used for fatigue damage analysis.Moreover,it was considered a linear accumulation damage through the Palmgren-Miner rule for the counting of stress cycles.The health monitoring data are adopted to obtain fatigue stress data and the rain flow counting method is used to count the amplitude varying fatigue stress.The proposed fatigue reliability approach in the paper can estimate the fatigue damage degree and its evolution law of bridge structures well,and also can help bridge engineers do the assessment of future service duration.
文摘对圆筒型浮式生产储卸油装置(Floating Production Storage and Offloading,FPSO)系泊锚链的面外弯曲(Out-of-Plane Bending,OPB)问题进行深入分析,对OPB发生风险和可能导致的疲劳损伤进行详细计算。分析结果显示,圆筒型FPSO系泊系统存在OPB影响,第一个自由链环是整个系泊系统中最关键和脆弱的环节。计算结果表明,系泊锚链的疲劳寿命为43.7 a,满足系泊系统的可靠性需求。研究提出的评估方法可为后续类似工程提供参考,对提高FPSO的可靠性与安全性具有参考意义。
