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Grouted connections are intensively used in offshore rigs, platforms as well as jacket and monopile offshore wind turbine structures. Being located in remote offshore conditions, these connections can experience considerable adverse loading during their lifetimes. Degradation was reported inside similar connections, which were installed in the last three decades. Grouting in the offshore sites may often be proven difficult, which eventually leads to reduced load-bearing capacity of connections in the long run. Thus, repair and rehabilitation of such connections should be planned ahead to minimize operational delays and costs. In this study, scaled grouted connections were manufactured using a novel mould, whose integrity were monitored using digital image correlation (DIC). The connections were loaded under static load to visualize the main failure pattern using distributed fibre optic sensors and acoustic emission (AE) analysis. Grouted connections were then repaired using a cementitious injectable grout. The effectiveness of the grout injection was monitored using dye penetration technique. Finally, specimens are reloaded to identify the potential of such repair for grouted connections. 相似文献
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It has been proposed that grade A should be replaced with a tougher steel for ship construction. This recommendation is not supported by casualty statistics. Brittle fractures have decreased from once every 10 ship years at the time of the Liberty ships, to once every 100 ship years in the 1950s, and now stand at around once every 10,000 ship years. The authors have developed a probabilistic fracture mechanics approach indexed to the Charpy 27 Joule temperature, T27J. This is used here to analyse the Liberty ship failures. Comparison with a databank of T27J values for grade A steel spanning 1920 to 1995 suggests that the Liberty ship steel was unusually brittle. The probability analysis shows good agreement between predicted and observed fracture casualty rates for the Liberty ships and helps explain why brittle fractures are now uncommon in grade A steel ships. 相似文献
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由于混凝土材料抗拉强度低的特点,单坡型桥梁钢筋混凝土护栏通常是带裂纹工作的。为了研究裂纹对于单坡型桥梁钢筋混凝土护栏防撞性能的影响,总结了单坡型桥梁钢筋混凝土护栏裂纹特点,并进一步分析了单坡型桥梁钢筋混凝土护栏裂纹的类型。在此基础上,本文采用文献资料调研、理论分析以及计算机仿真方法分析了单坡型桥梁钢筋混凝土护栏裂纹对其防护能力的影响,认为虽然混凝土材料在裂纹处不连续,但由于钢筋的存在,不会影响护栏作为纵向的连续结构整体发挥安全防护作用,因此裂纹对单坡型桥梁钢筋混凝土护栏的防护能力没有影响。本文最终通过实车碰撞试验对分析结果进行了验证。 相似文献
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文章简要介绍了福建省三明市南口岭公路隧道的病害情况、产生病害的原因分析,以及对病害的综合整治方案,对整治后的隧道衬砌受力进行了分析,提出的整治方案可供同类隧道病害整治中参考。 相似文献
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碳纤维布在连拱隧道衬砌裂缝病害治理中的应用 总被引:1,自引:0,他引:1
延安至安塞高速公路墩山连拱隧道主体工程完工后,衬砌出现了不同程度的裂缝和渗漏水等病害,通过对衬砌裂缝特征、产生原因的分析,并根据裂缝的开裂程度与发展规律,采用碳纤维布对隧道衬砌裂缝进行了局部修复和整体加固补强。由于在施工过程中严格控制施工工艺和施工质量,达到了预期效果。通过碳纤维加固模拟和监测表明:衬砌裂缝得到了有效控制,支护受力处于安全状态,围岩稳定,碳纤维布加固效果显著。 相似文献
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铁路桥梁墩身表面裂纹整治及安全性分析 总被引:1,自引:1,他引:0
《铁道标准设计通讯》2015,(6):93-96
针对某铁路特大桥在施工过程中出现的部分墩身表面裂纹,分析裂纹发生原因,应用静、动力分析方法对桥墩结构进行安全性评估,得出墩身表面裂纹对墩身强度及刚度等设计控制因素影响较小、不影响桥墩正常使用的结论,提出结构加固整治措施并付诸实施。建成后进行的行车检测表明,桥梁结构安全,完全满足运营要求。 相似文献