随机性验证荷载对既有建筑结构构件可靠度的影响分析  

Research on influence of random proof load on reliability of existing building structural members

作　　者：蒋利学 白雪 王卓琳 Jiang Lixue;Bai Xue;Wang Zhuolin(Shanghai Key Laboratory of Engineering Structure Safety,Shanghai Research Institute of Building Sciences Co,Ltd,Shanghai 200032,China)

机构地区：[1]上海市建筑科学研究院有限公司上海市工程结构安全重点实验室,上海200032

出　　处：《土木工程学报》2022年第7期39-46,共8页China Civil Engineering Journal

基　　金：国家重点研发计划(2017YFC0806100);上海市科学技术委员会科研计划(19DZ1202400)。

摘　　要：对既有建筑结构构件进行安全性评定时,容易推断其在已服役时间内的随机性验证荷载。以混凝土受弯、大偏压和轴压三类构件为例,研究了随机性验证荷载作用下结构构件可靠指标的时变规律。不考虑抗力退化时构件可靠指标和失效概率的时变规律分析表明:(1)经5年左右的验证荷载作用后,构件的失效概率均趋于与服役时间成正比;既有结构评定时的构件失效概率回复至零,且失效概率增长速率基本与原设计构件相同;(2)评定时的已服役时间越长、评估使用年限越短、永久荷载占比越大,验证荷载引起的构件可靠指标基本增量越大,而三类构件之间的可靠指标基本增量差异不大;(3)验证荷载引起的可靠指标综合增量由可靠指标基本增量和评估使用年限缩短引起的可靠指标增量构成,且后者大于前者;(4)评估使用年限不超过5年和已服役时间的一半时,验证荷载的有利作用较显著,采用基于良好结构状态的评定方法评定既有结构构件的安全性时应限定评估使用年限和已服役时间。完整的结构构件时变可靠指标分析应同时考虑抗力退化、验证荷载作用以及评估使用年限缩短的影响,验证荷载作用及评估使用年限缩短可抵消部分因抗力退化引起的可靠指标降低。While evaluating the safety of structural members in existing buildings,it is easy to deduce the random proof load in the service time.Taking concrete flexural members,compression members with large eccentricity and axial compression members as examples,the time-varying rule of the reliability index of the structural members under the proof load were studied.The time-varying rules of reliability index and failure probability of the structural members when the resistance degradation is ignored are analyzed.The results shows that:(1)After the proof load of about 5 years,the failure probability of members increases proportionally with the service time.When the existing structure is evaluated,the failure probability of the members returns to zero,and the growth rate of the failure probability is basically the same as that of the original design members.(2)The longer the service time,the shorter the assessment service life,the larger the proportion of the permanent load,the basic increment of reliability index of the structural members caused by the proof load is larger,and the difference among three types of structural members is little.(3)The comprehensive increment of reliability index caused by the proof load consists of the basic increment of reliability index and the increment of reliability index caused by the shortening of assessment service life,and the later is bigger than the former.(4)When the assessment service life is less than 5 years and one half of the service life,the beneficial effect of the proof load is significant.When the assessment method based on good structural state is adopted to evaluate the safety of the existing structural components,the assessment service life and service time should be limited.In the complete analysis oftime-varying reliability index of structural members,the influence of resistance degradation,proof load effect and the shortening of the assessment service life should be considered simultaneously.Proof load effect and the shortening of the assessment service life can of

关 键 词：验证荷载 既有建筑结构 可靠度 评估使用年限 失效概率 

分 类 号：TU312[建筑科学—结构工程]