複合環境促進装置による構造物の劣化機構の解明と耐久性設計法の確立

本研究项目对钢结构和混凝土结构的劣化机理和耐久性进行了为期3年的研究。主要研究内容是对结构构件进行环境加速试验。对公路桥面和桥面进行了疲劳试验。同时，对锈蚀钢构件的承载能力进行了分析研究。主要内容和研究成果如下：(1)焊接钢结构腐蚀环境试验：通过对实际结构的腐蚀调查，发现焊接构件比平面构件更容易发生腐蚀。因此，利用焊接模型进行了大量的环境加速试验，以验证这一趋势。通过与暴露试验结果的对比，阐明了其机理和加速速率。(2)锈蚀钢构件的屈曲强度：采用有限元方法编制非线性计算程序，对剩余荷载…进行了计算。对更多锈蚀钢构件的承载能力进行了研究，并推导出了计算公式。(3)钢筋在混凝土构件中的锈蚀：通过改变试件参数来研究钢筋在混凝土中的锈蚀情况。此外，混凝土涂层的可变性也通过了相同的环境试验。(4)拉索桥斜拉索的腐蚀机理：对水泥灌浆拉索的腐蚀进行了实验研究，指出拉索的温度重复是其腐蚀的主要原因。(5)预应力混凝土结构中的钢筋锈蚀：证实锈蚀是由于水泥灌浆锚索的相同原因造成的。(6)公路桥面板钢筋锈蚀与劣化面板疲劳寿命：通过电势腐蚀试验，研究了混凝土保护层剥落与钢筋锈蚀的关系。在此基础上，讨论了劣化板材的疲劳寿命和修复问题。(7)桥梁鞋的劣化：鞋上的主要现象之一是鞋下混凝土的劣化。通过疲劳试验，确定其主要原因为水环境下的疲劳破坏。较少

In this research project, researches on the mechanism of deterioration and durabily of steel and concrete structures were carried out for 3 years term. The main research was environmental accelerate tests for the structural members. Fatigue tests were carried out about deteriorations of the highway bridge slabs and shoes. Also, the load-carrying capacity of corroded steel members were investigated analytically. The main themes and their research results are as follows: (1)Environmental tests on Corrosion of Welded Steel Structures: From a survey about corrosion of actual structures, it is clear that welded parts are apt to corrode earlier than plane parts. So, many environmental accelerative tests were carried out to prove the trends using welded models. In a comparison with the exposure test results, the mechanism and acceleration rate were clarified. (2)Bucking Strength of Corroded Steel Members: By making a non-linear computer program by finite element method, residual load-carrying … More capacity of corroded steel members were investigated and an evaluation formula was derived. (3)Corrosion of Reinforcements in Concrete Members:Corrosion of reinforcements in concrete was investigated by changing the parameters of specimens. Also, varidity of concrete coat ings were approved through the same environmental tests. (4)Corrosion Mechanism of Stay- Cables in the Cable-Styed Brides: Corrosion of the cement grouted cables was reproduced experimentally and thermal repetiton of the cables was pointed out to be the main cause. (5)Corrosion of Tendon in Prestressed Concrete Structures: The corrosion were verified to occur due to same reason of the cement grouted cables. (6)Corrosion of Reinforcements in Highway Bridge Slabs and Fatigue Life of the Deteriorated Slabs: An potential corrosion test were carried out to investigate a relation between spalling of concrete cover and corrosion of reinforcements. Then, fatigue life and reparing of the deteriorated slabs were discussed. (7)Deterioration of Bridge Shoes:One of the main phenomena on shoes is the deterioration of concrete under the shoes. The main cause was proved as fatigue failure under water environment through the fatigue tests. Less