本文選題：火災 + 鋼筋混凝土梁��； 參考：《青島理工大學》2013年碩士論文

【摘要】：鋼筋混凝土結構在遭受火災后，構件的承載力、變形等都會受到不同程度的損傷，從而影響整個結構的耐久性和安全性，嚴重時會導致結構整體倒塌。對于處于海洋環(huán)境中的鋼筋混凝土結構，氯離子侵蝕會造成其鋼筋銹蝕，對構件抗火性能有何影響很少有人研究。 本文以快速氯離子侵蝕后的混凝土裂縫寬度作為損傷指標，建立損傷指標ω和混凝土構件抗火性能退化規(guī)律之間的關系，探究由于氯離子侵蝕引起的裂縫對混凝土截面溫度場畸變的影響，具體研究的內容如下： （1）對國內外關于鋼筋混凝土耐久性和抗火性能的研究成果進行總結，概括考慮海洋環(huán)境鋼筋混凝土結構的研究進展，為考慮海洋環(huán)境鋼筋混凝土梁的火災試驗研究提供理論基礎。 （2）本文共設計5根鋼筋混凝土梁試件，先進行快速氯離子侵蝕試驗，使其產生最大寬度為0.05mm、0.10mm、0.15mm、0.20mm的侵蝕裂縫，試驗中箍筋比縱筋銹蝕嚴重，氧氣濃度顯著影響侵蝕速率。對帶有不同侵蝕損傷（即裂縫寬度）試件進行火災試驗，通過對比各試件變形特點、溫度分布規(guī)律，得出不同試件相同位置測點升溫趨勢大致相同，但截面歷經(jīng)最高溫度相差較大，最大溫差達到300℃；裂縫寬度越大，試件歷經(jīng)最高溫度越高，撓度增長越快。 （3）對試件進行加載破壞試驗得到各構件受火后的殘余承載力，通過截面等效的簡化辦法計算得到各試件高溫后承載力理論值。通過高溫承載力實測值與理論值作對比，檢驗該簡化模型的可行性。通過對未損傷試件與損傷最大試件的高溫后殘余承載力作對比，得出受氯離子侵蝕試件的承載力退化幅度較大，表明侵蝕損傷對試件的高溫承載力有顯著的影響，，有必要對受氯離子侵蝕的混凝土結構或構件進行進一步的抗火研究，為海工、海岸鋼筋混凝土結構抗火設計提供理論依據(jù)。
[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

本文編號：1739398