高强圆钢管超高强混凝土柱三维本构模型及承载性能

The increase in the material strength of steel and concrete highlights the buckling problem of steel members and the brittle behavior of concrete. A reasonable application of the high strength materials with properly handling those byproducts of high strength will result in the saving of cost and materials. Ultra-high strength concrete (UHSC) filled circular high strength steel (HSS) tube is recognized as one of the best member type to take advantage of the high tensile strength of steel and high compressive strength of concrete, however, its application is limited by lacking of theoretical support and experimental research. This project will measure the autogenous shrinkage of UHSC to determine the mix design of concrete additive, and establish a hydrostatic pressure, deformation history and loading path dependent constitutive model of UHSC. The model parameters will be determined by a serious of uniaxial, biaxial and triaxial concrete test. Then, short column tests and long column tests (concentrically and eccentrically loaded) will be carried out and the test results will be used to verify the developed numerical model with implementation of the propose constitutive model of UHSC. A systematic parameter analysis will be performed by using the verified numerical model. Based on the analysis of the deformation capacity of UHSC filled circular HSS tubular columns, the criterion of failure mode will be proposed. The strength compatibility check between steel and concrete material will be carried out and the recommended combinations, which can achieve ductile failure and semi-ductile failure will be summarized. Finally, the design method of the ultimate resistance of UHSC filled circular HSS tubular columns will be proposed.

钢材和混凝土的高强化会导致钢构件稳定问题和混凝土脆性问题更严重。合理应用高强材料避免高强化带来的问题可节约建设成本与自然资源。高强圆钢管超高强混凝土是一种有效发挥两种高强材料性能的构件形式，但其设计和应用尚缺少理论依据和研究成果支持。本项目拟进行自收缩试验以确定超高强混凝土添加剂配比，构建静水压力、变形历程及加载路径相关的超高强混凝土本构模型，通过混凝土单、双、三轴系列试验确定模型参数；进行高强圆钢管超高强混凝土轴压短柱试验与长柱轴压、偏压极限承载力试验，通过试验结果与数值结果的对比验证所建超高强混凝土三维本构模型的有效性，采用验证的数值模型进行系统参数分析；归纳分析试验与参数分析结果，基于变形性能分析提出高强圆钢管超高强混凝土受压构件的破坏类型判定准则，确定可达延性、半延性破坏的不同牌号钢与混凝土强度匹配关系，建立高强圆钢管超高强混凝土柱受压极限承载力计算理论和设计方法。

合理应用高强材料可避免钢材和混凝土的高强化导致的钢构件稳定问题和混凝土脆性问题，达到有效节约建设成本与自然资源的效果。高强圆钢管超高强混凝土是一种有效发挥两种高强材料性能的构件形式。针对其设计和应用尚缺少理论依据和研究成果支持的问题，本项目进行自收缩试验优选了超高强混凝土添加剂配比，构建了静水压力、变形历程及加载路径相关的超高强混凝土本构模型，通过混凝土单、双、三轴系列试验确定了模型参数；进行了高强圆钢管超高强混凝土轴压短柱试验与长柱轴压、偏压极限承载力试验，通过试验结果与数值结果的对比验证了所建超高强混凝土三维本构模型的有效性，采用验证的数值模型进行了系统参数分析；通过归纳分析试验与参数分析结果，提出了基于变形性能的高强圆钢管超高强混凝土受压构件的破坏类型判定准则，确定了不同牌号钢与混凝土强度匹配关系，建立了高强圆钢管超高强混凝土柱受压极限承载力计算理论和设计方法。