钢管橡胶混凝土柱约束机理及力学性能研究

Rubberized concrete filled steel tubular columns are one of the most successful solutions to tackle the construction problem concerning the lower ductility of thinner high-strength steel tubes using in concrete filled steel tubular columns.They can take advantage of both the structural performance of concrete filled steel tubular columns and the improved ductility and energy dissipation capacities of rubberized concrete. The replacement of natural aggregates by rubber particles also allows the construction industry to solve the sustainability problems of recycling scrap tyres. However, there is a lack of information on the confinement mechanism and mechanical properties of rubberized concrete filled steel tubular columns. In view of this, the applicant intends to carry out some push-out tests and establish the bond-slip model between rubberized concrete and steel tubes. The experimental and numerical analysis method will be adopted to study the stiffness, load carrying capacity, ductility and capacity of energy behavior on rubberized concrete filled steel tubular columns under axial compression, eccentric compression, pure bending and cyclic loading. The influence of various parameters, such as rubberized concrete strength, rubber replacement and rubber particle size on the static and dynamic behavior will be investigated. Based on the current design guideline, the practical prediction methods to load bearing capacity under static load, the restoring force model of moment-curvature and load-displacement under cyclic load will be proposed accordingly. It is expected to form the corresponding design rules so that they can provide scientific evidence for real rubberized concrete filled steel tubular structures and design regulations.

钢管橡胶混凝土结构能够充分利用钢管混凝土柱的结构优势及橡胶混凝土良好的延性和耗能能力，不仅可以解决薄壁高强钢管混凝土塑性性能下降的工程问题，也为废旧橡胶的处理提供良好出路。目前，对钢管橡胶混凝土柱约束机理及力学性能的试验及理论研究还不够系统。鉴于此，申请人拟进行钢管橡胶混凝土柱的推出试验，确定钢管与橡胶混凝土界面的粘结滑移模型。通过对钢管橡胶混凝土长柱轴压、长柱偏压、构件纯弯和构件往复荷载作用下的试验和数值模拟研究，分析其在单调和滞回荷载作用下的柱刚度、承载力、延性和耗能能力，探讨橡胶混凝土强度、橡胶粉体积取代率、橡胶粉粒径等重要参数对其静力、动力性能的影响规律。并基于现有规范，提出钢管橡胶混凝土柱在静力荷载作用下承载力计算方法和往复荷载作用下弯矩—曲率和荷载—位移恢复力模型。以期为钢管橡胶混凝土的工程应用提供科学依据。

本研究基于橡胶混凝土具有较好的延性和耗能能力的特点，将橡胶混凝土填入钢管中，组成钢管橡胶混凝土构件，以期解决钢管塑性性能不强和废旧橡胶的处理等问题。主要研究内容和成果如下：(1) 进行了橡胶混凝土基本力学特性的试验。获得了橡胶混凝土的抗压强度、抗拉强度、弹性模量、拉（压）应力与拉（压）应变关系。(2) 进行了典型钢管橡胶混凝土构件力学性能试验研究。探讨了橡胶混凝土强度、橡胶粉体积取代率、橡胶粉粒径等试验参数对钢管橡胶混凝土构件破坏模态、承载力、刚度及抵抗变形能力等影响。混凝土内掺入橡胶粉后，钢管橡胶混凝土构件的破坏模态与普通钢管混凝土的类似，极限承载力虽有所下降，但刚度和抵抗变形能量均有所提高。在橡胶混凝土替代率合理的情况下，钢管橡胶混凝土构件可以应用于对塑性性能要求较高、强度性能要求不高的结构中。(3) 在有限元分析和系统参数分析基础上，利用日本规程AIJ（2008）、英国规程BS5400（2005）、欧洲规程Eurocode4（2005）及我国规程GJB4142-2000、DB21/T1746-2009和GB50936-2014等现有规程对钢管橡胶混凝土构件在各种荷载作用下的承载力进行计算，结果表明以上6种规程均能用来计算钢管橡胶混凝土构件的承载力，计算结果偏于保守，其中欧洲规程Eurocode4（2005）计算所得的承载力与试验结果、有限元模拟结果最为接近。通过以上研究，给出钢管橡胶混凝土构件的合理的构造措施和设计建议，以期为有关工程应用提供理论依据。