考虑海洋环境损伤的钢筋混凝土梁抗火性能试验研究

发布时间：2018-04-12 10:43

  本文选题：火灾 + 钢筋混凝土梁　； 参考：《青岛理工大学》2013年硕士论文

【摘要】：钢筋混凝土结构在遭受火灾后，构件的承载力、变形等都会受到不同程度的损伤，从而影响整个结构的耐久性和安全性，严重时会导致结构整体倒塌。对于处于海洋环境中的钢筋混凝土结构，氯离子侵蚀会造成其钢筋锈蚀，对构件抗火性能有何影响很少有人研究。 本文以快速氯离子侵蚀后的混凝土裂缝宽度作为损伤指标，建立损伤指标ω和混凝土构件抗火性能退化规律之间的关系，探究由于氯离子侵蚀引起的裂缝对混凝土截面温度场畸变的影响，具体研究的内容如下： （1）对国内外关于钢筋混凝土耐久性和抗火性能的研究成果进行总结，概括考虑海洋环境钢筋混凝土结构的研究进展，为考虑海洋环境钢筋混凝土梁的火灾试验研究提供理论基础。 （2）本文共设计5根钢筋混凝土梁试件，先进行快速氯离子侵蚀试验，使其产生最大宽度为0.05mm、0.10mm、0.15mm、0.20mm的侵蚀裂缝，试验中箍筋比纵筋锈蚀严重，氧气浓度显著影响侵蚀速率。对带有不同侵蚀损伤（即裂缝宽度）试件进行火灾试验，通过对比各试件变形特点、温度分布规律，得出不同试件相同位置测点升温趋势大致相同，但截面历经最高温度相差较大，最大温差达到300℃；裂缝宽度越大，试件历经最高温度越高，挠度增长越快。 （3）对试件进行加载破坏试验得到各构件受火后的残余承载力，通过截面等效的简化办法计算得到各试件高温后承载力理论值。通过高温承载力实测值与理论值作对比，检验该简化模型的可行性。通过对未损伤试件与损伤最大试件的高温后残余承载力作对比，得出受氯离子侵蚀试件的承载力退化幅度较大，表明侵蚀损伤对试件的高温承载力有显著的影响，，有必要对受氯离子侵蚀的混凝土结构或构件进行进一步的抗火研究，为海工、海岸钢筋混凝土结构抗火设计提供理论依据。
[Abstract]:After the fire, the bearing capacity and deformation of the reinforced concrete structure will be damaged to varying degrees, which will affect the durability and safety of the whole structure, and will lead to the collapse of the whole structure.For reinforced concrete structures in marine environment, chloride ion erosion will cause corrosion of steel bars, and how to influence the fire resistance of members is rarely studied.In this paper, the crack width of concrete after rapid chloride ion erosion is taken as the damage index, and the relationship between the damage index 蠅 and the degradation law of fire resistance of concrete members is established.The effect of cracks caused by chloride ion erosion on the temperature field distortion of concrete cross-section is investigated. The specific contents of the study are as follows:1) summarize the research achievements on the durability and fire resistance of reinforced concrete at home and abroad, and consider the research progress of reinforced concrete structures in marine environment.It provides a theoretical basis for the fire test of reinforced concrete beams in marine environment.In this paper, five specimens of reinforced concrete beams are designed, and the rapid chloride erosion tests are carried out to produce corrosion cracks with a maximum width of 0.05mm / 0.10mm / 0.15mm / 0.20mm. In the test, the stirrups are more serious than the longitudinal bars, and the oxygen concentration has a significant effect on the erosion rate.The fire test was carried out on the specimens with different erosion damage (i.e. crack width). By comparing the deformation characteristics and temperature distribution of the specimens, it was concluded that the temperature rising trend of the same locations of the different specimens was roughly the same.However, the maximum temperature difference reached 300 鈩

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