【作者】 朱美春；

【导师】 王清湘；

【作者基本信息】 大连理工大学 ， 结构工程， 2006， 博士

【摘要】 为了更好地适应当代工程结构向大跨、高耸、重载方向发展和工业化生产施工的需要,本文将钢骨混凝土、方钢管混凝土与高强高性能混凝土技术结合起来,提出了一种重载柱设计的新模式,即钢骨-方钢管自密实高强混凝土组合柱。该组合柱是在方钢管内填充自密实高强混凝土和型钢而形成。本文结合国家自然科学基金项目《钢-混凝土组合重载柱设计的新模式》(50078008),主要开展了以下几方面的工作: 1、成功配制出立方体抗压强度分别为73.2MPa和103.8MPa的两种自密实高强高性能混凝土,完全实现了试件的免振成型。 2、进行了14根轴心受压钢骨-方钢管自密实高强混凝土短柱的试验研究。试验结果表明:钢骨-方钢管自密实高强混凝土短柱试件的破坏形态与不含钢骨的方钢管自密实高强混凝土试件的破坏形态明显不同;经过振捣的试件与自密实试件的变形曲线和极限强度均没有明显差异;混凝土的强度、方钢管的宽厚比和钢骨的用量都对组合柱的受力性能有着显著影响;核芯混凝土的存在改变了方钢管板件的局部屈曲模式,使方钢管混凝土的宽厚比限值提高为空方钢管宽厚比限值的1.6倍。 3、在试验研究的基础上建立了钢骨、方钢管和核芯自密实高强混凝土的单轴应力-应变模型,其中方钢管的模型考虑了双轴效应,核芯混凝土的模型考虑了方钢管的约束作用和钢骨对其延性的影响。然后利用纤维模型法对轴心受压短柱荷载-变形性能进行分析,理论分析结果与试验结果吻合良好。最后在试验和理论研究的基础上,提出了可供工程设计参考的钢骨-方钢管自密实高强混凝土短柱轴压承载力计算公式。 4、进行了8根轴心受压钢骨-方钢管自密实高强混凝土长柱的试验研究。试验前,用超声法对内填自密实高强混凝土的质量进行检测,超声检测结果表明核芯混凝土的密实性与质量均匀性良好,表明本文配置的自密实高强混凝土可以在组合柱构件中实现自密实的效果。试验结果表明:长细比是影响组合长柱轴压受力性能的最主要因素。随着长细比的增大,试件的承载能力、极限纵向变形率以及延性明显降低。 5、利用切线模量理论,对轴心受压钢骨-方钢管自密实高强混凝土柱的稳定承载力进行了理论分析。与试验结果的对比表明,该方法可以对轴压组合柱的稳定承载力给出良好的预测。最后在试验研究和理论分析的基础上,给出可供工程设计参考的组合柱轴压稳定承载力的实用计算公式。更多还原

【Abstract】 Adapting to the development of modern structures toward big-span, high-rise, heavy-load and the need of industrialized production and construction, a new design model of heavy-loaded columns is proposed by combining the steel-reinforced concrete, concrete-filled steel tube and high-strength high-performance technology together, that is square steel tube columns filled with steel-reinforced self-consolidating high-strength concrete. In this type of composite columns, steel section is inserted into steel tube and self-consolidating high-strength concrete is filled into the void between them. According to the project of National Natural Science Foundation named "a new design model of steel-concrete composite columns" (No. 50078008), investigations are carried out as follows:1. Two classes of self-consolidating high-strength concrete with cubic compressive strength of 73.2MPa and 103.8MPa respectively are successfully compounded, which achieve the cast of specimens without vibration.2. Fourteen composite stub columns are tested under axial compression. The experimental results show that failure mode of the new type of composite columns is quite different from that of composite columns without steel section; the ultimate strength and deformation behavior of self-consolidated columns and vibrated columns are almost the same; concrete strength, width-to-thickness ratio and the area of encased steel section have significant effect on the bearing-capacity and ductility of the columns; the existence of the core concrete changes the local buckling mode of the square tubes, which contributes to improve the width-to-thickness ratio limit of the composite columns to be 1.6 times that of the empty square steel tubes.3. Based on the experimental results, the axial stress-strain models for steel section, square steel tube and confined core concrete are proposed, in which the model of square steel tube considers the biaxial effect and the model of the core concrete considers the confining effect from the tube and the effect of steel section on its ductility. The models are used to calculate the load-deformation relationship for composite stub columns under axial load by fiber model method. The calculated ultimate strength and postpeak response agree well with the test results. Finally, the formula for predicting the axial bearing-capacity of the composite stub columns is proposed.4. Eight composite long columns are tested under axial compression. Before loading, the ultrasonic method is used to test the quality of the core self-consolidating high-strength concrete.It shows that the quality of the core concrete is uniform and no segregation occurs during casting and placing. The experimental results indicate that the slenderness ratio (Lq/B) has the most significant effect on the behavior of the composite long columns. Maximum axial load and its corresponding strain of specimens decrease with the increase oiLJB.5. The stability capacity of the composite long columns under axial load is analyzed by tangent modulus theory. Comparison between the theoretical and experiemtal results shows that this method can give a favorable prediction for the stability capacity of the composite long columns. Based on the experimental and theoretical results, formulas for estimating the axial stability capacity of the composite long columns are proposed.6. Three composite flexural specimens are tested under pure bending. The test results indicate that the deformations of square steel tube and steel section during bending are approximately consistent. Superposition method and ultimate state design method are used to derive the flexural capacity of the composite members. Both methods can give a conservative prediction for flexural capacity of the the composite members.7. Fourteen composite column specimens are tested under constant compressive axial load and cyclic lateral load. Test results show that steel section and concrete filled in it compose a core column which prevents the formation of fracture plane in concrete, thus improves the collapse-resistance ability of the newly proposed columns; axial load ratio, width-to-thickness ratio, strength of concrete, and the content of steel section have significant effect on strength, ductility, energy dissipation and stiffness of the composite columns, among which axial load ratio is the most important factor; to ensure that the composite columns have good ductility, it is necessary to limit the axial load ratio.8. The calculation formulas for cross-section bearing-capacity of the composite columns are derived by superposition method. The calculated results agree well with the results obatian by fiber model method, and tend to safety when compared with the test results. The proposed method is suitable to be used in engineering design.更多还原