基于监测样本的大跨索桥疲劳应力概率分布函数的参数估计和检验

疲劳应力监测是大跨桥梁结构健康监测和安全评估的关键环节。为了对桥梁实际运营状态和应力水平有总体而全面的认识，就需要对采集的大量数据进行统计分析获取其概率分布函数。以润扬大桥结构健康监测系统记录的悬索桥钢箱梁应变时程数据为基础，分析了润扬悬索桥半年内疲劳应力谱的特征．基于监测得到的应力谱样本进行了疲劳应力幅概率密度函数的参数估计和检验，拟合得到疲劳损伤增量的概率密度函数。研究结果表明：目前润扬桥应变监测部位的等效应力幅较低，最大应力幅远未达到引起疲劳损伤的阎值：半年应变样本的相对疲劳损伤增量服从对数正态分布或者Weibull分布；且以监测数据分析得到的相对疲劳损伤增量所得到的可靠度指标较高，失效概率较低，与当前工作应力状态较低的现状相吻合。

Parameter Evaluation in Probability Density Function of Fatigue Stress of Long Suspension Bridge Based on Monitoring Data

The monitoring of fatigue stress is a key issue of structural health monitoring and safety assessment of long-span bridges.In order to acquire roundly actual state and stress level,statistical analysis of vast data recorded to obtain probability distributing function is needed.This paper aims at investigating the feature of fatigue stress amplitudes on the steel box-girders under service loading on the basis of strain history data recorded by structural health monitoring system installed on Runyang Suspensi...