严寒地区冻融混凝土内钢筋应力滑移模型及OpenSEES有限元模拟

在严寒地区冻融混凝土与钢筋局部粘结滑移模型的基础上,基于冻融混凝土内钢筋沿锚固长度的受力机理分析及迭代过程分析,建立了冻融混凝土内钢筋应力滑移计算方法,提出了冻融混凝土内钢筋的应力滑移关系骨架曲线。基于有限元计算软件OpenSEES,将推导的冻融混凝土内钢筋应力滑移关系曲线嵌套于零长度截面单元,并将该单元应用于梁柱纤维模型,对3根既有的冻融钢筋混凝土框架柱进行模拟,与试验结果进行对比分析。结果表明,冻融钢筋混凝土柱有限元模型的模拟结果与试验结果的符合程度良好,从构件层次验证了推导的冻融混凝土内钢筋应力滑移关系曲线具有较好的精度和可靠性。研究成果可为严寒地区冻融混凝土内钢筋应力滑移推导及有限元模拟提供理论参考。

Stress-Slip Model of Steel Bar for Freeze-Thaw Concrete in Severe Cold Regions and OpenSEES Finite Element Simulation

On the basis of the local bond-slip model of freeze-thaw concrete and steel bar in severe cold regions, based on the analysis of the force mechanism of steel bar along anchorage length in the freeze-thaw concrete and the analysis of the iterative process, a calculation method for the steel bar stress-slip in the freeze-thaw concrete was established. The skeleton curve of stress slip relationship for steel bar in freeze-thaw concrete was proposed. Then, based on the finite element calculation software OpenSEES, the deduced stress-slip curve of steel bar in the freeze-thaw concrete was nested in the zero-length section element, and the element was applied to the beam column fiber model. The three existing freeze-thaw reinforced concrete frame columns were simulated and then compared with the test results. The results show that the numerical results of the freeze-thaw reinforced concrete column finite element model are in good agreement with the test results. It is verified from the component level that the deduced stress-slip curve of steel bar in the freeze-thaw concrete has good accuracy and reliability. The research results provide a theoretical reference for the derivation and finite element simulation for the stress slip of steel bar in freeze-thaw concrete in severe cold regions.