蔡健, 魏沐杨, 罗赤宇, 陈庆军, 蚁原野, 张帆. 弯曲荷载与氯盐侵蚀共同作用下的预应力混凝土梁耐久性能研究[J]. 工程力学, 2018, 35(7): 208-218,242. DOI: 10.6052/j.issn.1000-4750.2017.03.0256
引用本文: 蔡健, 魏沐杨, 罗赤宇, 陈庆军, 蚁原野, 张帆. 弯曲荷载与氯盐侵蚀共同作用下的预应力混凝土梁耐久性能研究[J]. 工程力学, 2018, 35(7): 208-218,242. DOI: 10.6052/j.issn.1000-4750.2017.03.0256
CAI Jian, WEI Mu-yang, LUO Chi-yu, CHEN Qing-jun, YI Yuan-ye, ZHANG Fan. DURABILITY OF PRESTRESSED CONCRETE BEAMS UNDER SIMULTANEOUS FLEXURAL LOAD AND CHLORIDE EROSION[J]. Engineering Mechanics, 2018, 35(7): 208-218,242. DOI: 10.6052/j.issn.1000-4750.2017.03.0256
Citation: CAI Jian, WEI Mu-yang, LUO Chi-yu, CHEN Qing-jun, YI Yuan-ye, ZHANG Fan. DURABILITY OF PRESTRESSED CONCRETE BEAMS UNDER SIMULTANEOUS FLEXURAL LOAD AND CHLORIDE EROSION[J]. Engineering Mechanics, 2018, 35(7): 208-218,242. DOI: 10.6052/j.issn.1000-4750.2017.03.0256

弯曲荷载与氯盐侵蚀共同作用下的预应力混凝土梁耐久性能研究

DURABILITY OF PRESTRESSED CONCRETE BEAMS UNDER SIMULTANEOUS FLEXURAL LOAD AND CHLORIDE EROSION

  • 摘要: 当前在进行海工混凝土结构受氯盐侵蚀的耐久性研究时往往忽略了混凝土力学损伤的影响,这可能会导致高估结构的耐久性能。该文提出了在数值分析中引入损伤因子实现综合考虑结构损伤影响及氯盐侵蚀共同作用的分析方法,通过干湿循环的氯盐侵蚀试验与数值模拟分析,研究遭受氯盐腐蚀且受到长期荷载作用的预应力混凝土梁的耐久性能。结果表明,数值分析结果和试验结果吻合良好。参数分析结果表明:0.2mm宏观裂缝的出现对氯离子浓度有着较为显著的影响,未出现宏观裂缝时,拉应力对氯离子输运的影响较为有限;荷载比的大小影响结构的损伤范围和程度,进而影响氯离子在混凝土内的传输;梁构件施加预应力后,在15%和30%两种低荷载比状态下延缓其力学损伤(裂缝)的开展,减小荷载作用对氯离子扩散系数的增大效应,有效提高构件的抗氯盐侵蚀性能,当荷载比增加到45%以上,普通钢筋混凝土梁相对于预应力梁的氯离子浓度增比降至10%以内,这表明较高应力比下预应力对梁抗氯盐侵蚀能力的影响减弱。

     

    Abstract: Damage mechanics of concrete are often ignored in the durability study on chloride corrosion tests of offshore engineering structures, hence the durability of structures is overrated. This paper presents a study on introducing a damage factor to combine load and corrosion in numerical analysis of the durability of offshore structures. The wetting-drying tests were carried out, and the finite element model was established in order to study the durability of prestressed concrete beams under the chloride corrosion environment and long-term loadings. The results obtained from numerical analysis agreed well with test results. The finite element parametric analysis showed that 0.2mm macro-cracks have a significant influence on the chloride ion concentration, and the effect of tensile stresses on the chloride transport is limited when macro-cracks are not present. The loading ratio affects the damage range and the extent of the structure, which in turn affects the transfer of the chloride ions in concrete. The prestress delays the development of the mechanical damage in beams at 15% and 30% loading ratios, and reduces the loading effect on the coefficient of chloride ion diffusion, which improves the chloride resistance of the member. When the loading ratio increases to greater than 45%, compared to the prestressed beam, the increase in chloride ions in the normal reinforced concrete beams of chloride ion concentration is less than 10%, which means the influence of the prestress effect on the chloride resistance of the beam is weakened with higher loading ratios.

     

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