Effect of Fill Materials and their Filling Method on Strength and Ductility of Filled Steel Tubes

尽管人们为钢管混凝土的发展付出了巨大的努力，但钢管内填充的普通水泥混凝土存在一些缺陷或局限性，这些缺陷和局限性并不是钢管所能缓解的（如抗拉强度和粘结强度低、耐久性低、收缩率高、密度大、反应性高），从而阻碍了钢管混凝土的多样化应用。此外，水泥混凝土不适合建筑的特定要求，例如，在钢管柱的改造中，需要高延性增加和低强度增加，以及低密度，水泥混凝土不适用。即使对于目前使用的普通水泥钢管混凝土构件，由于不同国家或机构提出的设计规范存在很大差异，仍然需要广泛的数据库。主要目的是通过实验和分析研究填充钢管构件的结构响应，填充不同性能的聚合物和聚合物基材料，并承受几种形式的加载。聚合物或聚合物基材料在建筑行业引起了越来越多的关注，因为它们具有混凝土的补充和/或互补特性，即更高的抗压、抗拉和粘接强度，更低的重量和收缩率，高延展性和回弹性，以及抗物理和化学侵蚀。研究了几种填充型钢短柱和短梁的压弯性能、钢管与填充材料的界面相互作用、模拟多向荷载对钢柱的影响以及填充型钢短柱的循环性能。

Despite enormous efforts devoted to the evolvement of concrete filled steel(CFTs), the ordinary cement concrete used in filling the steel tube has certain drawbacks or limitations that are not mitigated by the encasing steel tube (e. g. low tensile and bond strengths, low durability, high shrinkage, high density and high reactivity), thus presenting a hindrance to the diverse application of CFTs. Further, cement concrete is not amenable to specific requirements of construction e. g. in retrofitting of steel tubular columns where high increase in ductility combined with low increase in strength, as well as low density are needed cement concrete is not applicable. Even for the currently used ordinary cement concrete filled steel tubular members(CFT)extensive data-base is still required since wide discrepancies exist between the design codes that have been proposed by different countries or institutions.The main objective was to experimentally and analytically study the structural response of filled steel tubular members, filled with polymers and polymer-based materials of varied properties and subjected to several forms of loading. Polymers or polymer-based materials are attracting increased attention in the construction industry due to the supplementary and/or complementary properties to concrete that they posses viz higher compressive, tensile and adhesive strengths, lower weight and shrinkage, high ductility and resilience, and resistance to physical and chemical attack. The study investigated the compressive and flexural behaviors of several types of filled steel stub columns and beams, interface interaction between the steel tube and fill material, effects of simulated multi-directional loads on steel columns and cyclic behavior of filled steel tubular columns.