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某高层住宅楼其中某一层部分剪力墙墙体混凝土强度不足,无法到达设计和使用要求,需要进行补强、加固。通过现场情况鉴定,对不同加固方案进行综合比较,采取置换加固施工技术进行处理。通过对原结构进行置换加固设计和置换加固施工,用强度等级高的混凝土置换掉原来强度等级低的混凝土,从而提高结构承载力,以达到设计和使用要求。 相似文献
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某工程由于预拌混凝土质量问题引起基础局部混凝土强度达不到设计要求,须停止上部结构施工进行基础加固处理.对加固部分基础采用钢支撑托换,凿除承台、地梁及底板混凝土,钢筋替换后重浇混凝土.加固期间加强监控,解决了质量事故问题,保证了上部继续施工. 相似文献
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混凝土结构工程加固方案的确定首先要保证安全,在此基础上,同时考虑方案的经济性和便于施工,最终设计出合理的加固方案,取得良好的社会效益和经济效益。只有施工技术先进,施工作业方便、加固效果好,经济社会效益高的方案才属于一个优秀的加固方案。文章首先对混凝土结构工程的加固技术进行介绍,在此基础上对结构加固的发展做了展望。 相似文献
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工程施工中由于设计原因、施工原因等造成工程结构构件强度不够或者构件出现质量事故,需对工程构件进行加固处理,本文中介绍了目前混凝土加固最新方法——碳纤维布结构加固。 相似文献
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不同加载路径下钢筋混凝土框架柱抗震性能的试验研究 总被引:1,自引:0,他引:1
本文对九根不同轴压比的钢筋混凝土悬臂柱进行了不同加载路径下静力周期反复荷载的试验研究。加载路径有单八字形、方形和圆形三种,并对变轴力加载情况作了初步探讨。主要讨论了加载路径和轴压比对构件强度和延性等抗震性能的影响。试验结果表明:加载路径对柱的强度和延性以及钢筋的粘结滑移等有明显影响;柱内存在明显的双轴耦合作用;变轴力加载使柱的延性和刚度比定轴力加载有所下降。 相似文献
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体外绕丝约束混凝土轴压特性的试验研究 总被引:1,自引:0,他引:1
通过16个体外缠绕不同间距细钢丝绳的混凝土圆柱体试件的轴心受压试验,研究了该类约束混凝土的受力特性。结果表明,体外绕丝约束混凝土的抗压强度和延性有很大程度的提高和改善,有望在钢筋混凝土受压构件加固中应用。 相似文献
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This paper presents the experimental results for a series of H steel columns under fire load. The width-to-thickness ratio of steel plates and the slenderness ratios of steel columns are two dominating factors linked to local buckling and global buckling of columns, respectively. To evaluate the influence of these two factors on the structural behavior of steel columns in fire conditions, a series of H steel columns were loaded to their limit states at specified temperature levels. The steady state method has been adopted in order to derive the structural behavior of steel columns at specified temperatures directly.On the basis of the experimental results, it has been found that steel columns with non-compact section are able to reach yield strength at elevated temperature. That is, the width-to-thickness ratio, designed in accordance with current ambient temperature specifications, is capable of preventing brittle failure of steel columns in fire conditions. Depending on the slenderness ratio, the failure of steel columns may change from global buckling at ambient temperature to local buckling at elevated temperature. For plastic section columns with a slenderness ratio greater than 50, column strength drops dramatically to 40% of its strength at ambient temperature. At temperature levels of 500 °C, the column retains more than 70% of its ambient temperature strength if the slenderness ratio of the column is less than 50. However, in the case of temperature levels exceeding 500 °C, or when the slenderness ratio is greater than 50, column strength drops significantly. On the basis of this study, it is tentatively suggested that 500 °C be adopted as the critical temperature for steel members subjected to compression in order to ensure that the column strength keeps higher than 2/3 of the ambient temperature yield strength. The slenderness ratio of steel columns should be limited to 50, so as to prevent brittle failure of steel columns under fire attack. 相似文献
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Required length of restraint for steel columns in concrete foundations. Steel columns are connected frequently bending resistant to concrete substructures. With this type of construction the required length of restraint must be specified and the load‐carrying capacity of the steel columns within the range of the concrete foundations has to be verified. In the report consistent load‐carrying models are presented, which are considering the ultimate plastic load‐carrying capacity of cross sections and new calculation models according to Eurocode 3 for locals verifications. The verification conditions are formulated for steel columns made of rolled and welded I‐sections, which are stressed by one‐ or two‐axial bending with compression normal force. For columns with rolled sections calculation adds are given, which makes it possible to read off directly the required length of restraint. 相似文献