再生混凝土质量控制及梁时变可靠度分析
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摘要
基于再生骨料来源复杂、具有变异性等特点,考虑由此引起的再生混凝土的变异性和时变性,对再生混凝土梁的时变可靠度进行研究,为再生混凝土受力构件的设计提供理论依据。基于时变可靠度计算方法,分析了再生混凝土梁的抗弯安全时变可靠度。案例分析表明,再生混凝土梁初始可靠指标为3.30,随着服役时间的增长,可靠指标逐渐降低,对应的失效概率逐渐增加。当服役时间为50年时,失效概率为0.0012,可靠指标为3.03,下降8.18%;当服役时间为100年时,失效概率为0.0114,可靠指标为2.28,下降30.91%。变参数分析结果表明,再生混凝土强度、配筋率和保护层厚度对时变可靠度的影响显著。提高再生混凝土强度,提高配筋率和增加保护层厚度,都可以提高时变可靠指标,保证再生混凝土梁满足可靠度要求。
Recycled aggregates are reclaimed from multiple sources and thus the variability of properties needs to be concerned. Therefore, the time-dependent reliability of recycled aggregate concrete(RAC) beams was analyzed considering the variability and time-dependent properties of RAC caused by recycled aggregates, which can provide design guidelines for RAC components. Based on the existing methods, the safety time-dependent reliability of RAC beams subjected to bending moment was analyzed. The case study shows that the initial reliability index is 3.30, and it decreases with the increase of service time and the corresponding failure probability increases. When the service time is 50 years, the failure probability is 0.0012 and the reliability index is 3.03, which is decreased 8.18%. When the service time is 100 years, the failure probability is 0.0114 and the reliability index is 2.28, which is decreased 30.91%. The parametrical analysis shows that the RAC strength, reinforcement ratio and the thickness of concrete cover have obvious influence on the reliability. Increasing the RAC strength, reinforcement ratio and the thickness of concrete cover can make the RAC beam meet the requirement of reliability.
Recycled aggregates are reclaimed from multiple sources and thus the variability of properties needs to be concerned. Therefore, the time-dependent reliability of recycled aggregate concrete(RAC) beams was analyzed considering the variability and time-dependent properties of RAC caused by recycled aggregates, which can provide design guidelines for RAC components. Based on the existing methods, the safety time-dependent reliability of RAC beams subjected to bending moment was analyzed. The case study shows that the initial reliability index is 3.30, and it decreases with the increase of service time and the corresponding failure probability increases. When the service time is 50 years, the failure probability is 0.0012 and the reliability index is 3.03, which is decreased 8.18%. When the service time is 100 years, the failure probability is 0.0114 and the reliability index is 2.28, which is decreased 30.91%. The parametrical analysis shows that the RAC strength, reinforcement ratio and the thickness of concrete cover have obvious influence on the reliability. Increasing the RAC strength, reinforcement ratio and the thickness of concrete cover can make the RAC beam meet the requirement of reliability.
引文
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[7]李秋义,李云霞,朱崇绩.颗粒整形对再生粗骨料性能的影响[J].材料科学与工艺,2005,13(6):579-581.
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[11]江见鲸,李杰,金伟良.高等混凝土结构理论[M].北京:中国建筑工业出版社,2007.
[12]WANG L,MA Y F,ZHANG J R,et al.Probabilistic analysis of corrosion of reinforcement in RC bridges considering fuzziness and randomnesss[J].Journal of Structural Engineering,2013,139(9):1529-1540.
[2]LIN Y H,TYAN Y Y,CHANG T P,et al.An assessment of optimal mixture for concrete made with recycled concrete aggregates[J].Cement and Concrete Research,2004,34(8):1373-1380.
[3]SILVA R V,DE BRITO J,DHIR R K.Properties and composition of recycled aggregates from construction and demolition waste suitable for concrete production[J].Construction and Building Materials,2014,65:201-217.
[4]XIAO J Z,LI W G,CORR D J,et al.Effects of interfacial transition zones on the stress-strain behavior of modeled recycled aggregate concrete[J].Cement and Concrete Research,2013,52:82-99.
[5]LI W G,XIAO J Z,SUN Z H,et al.Interfacial transition zones in recycled aggregate concrete with different mixing approaches[J].Construction and Building Materials,2012,35:1045-1055.
[6]SHI C,LI Y,ZHANG J,et al.Performance enhancement of recycled concrete aggregate-a review[J].Journal of Cleaner Production,2016,112:466-472.
[7]李秋义,李云霞,朱崇绩.颗粒整形对再生粗骨料性能的影响[J].材料科学与工艺,2005,13(6):579-581.
[8]裴永刚,谭文辉.工程结构时变可靠度理论的发展与应用[J].工业建筑,2005,35(S1):135-138.
[9]张俊芝.服役工程结构可靠性理论及其应用[M].北京:中国水利水电出版社,2007.
[10]贡金鑫,赵国藩.考虑抗力随时间变化的结构可靠度分析[J].建筑结构学报,1998,19(5):43-51.
[11]江见鲸,李杰,金伟良.高等混凝土结构理论[M].北京:中国建筑工业出版社,2007.
[12]WANG L,MA Y F,ZHANG J R,et al.Probabilistic analysis of corrosion of reinforcement in RC bridges considering fuzziness and randomnesss[J].Journal of Structural Engineering,2013,139(9):1529-1540.