钢管混凝土翼缘工字形梁弯扭屈曲和畸变屈曲理论与设计方法研究

In high-rise and long span structures, I-beam with concrete-filled steel tubular flange has many advantages. However, it has diverse composition (open–closed/solid) and different materials properties (steel/concrete), the design formulas of buckling for steel beam can not be copied directly. This project will ①Based upon the unified mathematical and mechanical method, establish the theory of flexure and torsion as well as the theory of elastic flexural-torsional buckling and distortional buckling for I-beam with concrete-filled steel tubular flange. And considering the influence of elastic restraint, and following the energy variational method model and differential equation model, the approximate analytical solutions for the equations of elastic flexural-torsional buckling and distortional buckling of simply supported beam and continuous beam can be obtained. Its correctness can be verified through the results of experiments and FEM analysis; ②Complete FEM numerical simulation research of elastic and elasto-plastic flexural-torsional buckling and distortional buckling for 600 model beams; ③Complete experimental research on elastic and elasto-plastic flexural-torsional buckling and distortional buckling for 36 specimen beams (24 for simply supported beams, 12 for continuous Beams with double equal spans); ④Considering the effects of material strength, ratio of steel, ratio of elastic modulus of materials, elastic constraint conditions and load conditions, put forward a set of simplified design formulas for the load of elastic and elasto-plastic flexural-torsional buckling and distortional buckling for I-beam with concrete-filled steel tubular flange. In conclusion, this project has significant academic value and practical application value.

在高层及大跨度结构中，钢管混凝土翼缘工字形梁具有很多优势，但其构成多元（开口—闭口—实体），且材料特性（钢/混凝土）各异，因而无法直接套用现有的钢梁屈曲设计公式。本项目将①基于统一的数学和力学方法，建立钢管混凝土翼缘工字形梁弯曲与扭转理论以及弹性弯扭屈曲与畸变屈曲理论，并考虑弹性约束的影响，依据能量变分法模型和微分方程模型的求解得到简支梁、连续梁弹性弯扭屈曲和畸变屈曲方程的近似解析解。通过试验和FEM分析结果验证其正确性；②完成600根模型梁弹性与弹塑性弯扭屈曲和畸变屈曲的FEM数值模拟研究；③完成36根试件梁（简支梁24根，双等跨连续梁12根）弹性与弹塑性弯扭屈曲和畸变屈曲的试验研究；④考虑材料强度、含钢率、材料弹性模量之比、弹性约束工况、荷载工况等参数的影响，提出一套钢管混凝土翼缘工字形梁弹性与弹塑性弯扭屈曲和畸变屈曲荷载的简化设计公式。综上，本项目具有重要的学术价值和实际应用价值。

在高层及大跨度结构中，钢管混凝土翼缘工字形梁具有很多优势，但其构成多元（开口—闭口—实体），且材料特性（钢/混凝土）各异，因而无法直接套用现有的钢梁屈曲设计公式。本项目将①基于统一的数学和力学方法，建立钢管混凝土翼缘工字形梁弯曲与扭转理论以及弹性弯扭屈曲与畸变屈曲理论，并考虑弹性约束的影响，依据能量变分法模型和微分方程模型的求解得到简支梁、连续梁弹性弯扭屈曲和畸变屈曲方程的近似解析解。通过试验和FEM分析结果验证其正确性；②完成560根模型梁弹性与弹塑性弯扭屈曲和畸变屈曲的FEM数值模拟研究；③完成36根试件梁和柱的约束扭转、弹性与弹塑性弯扭屈曲和畸变屈曲的试验研究；④考虑材料强度、含钢率、材料弹性模量之比、弹性约束工况、荷载工况等参数的影响，提出一套钢管混凝土翼缘工字形梁弹性与弹塑性弯扭屈曲和畸变屈曲荷载的简化设计公式。综上，本项目具有重要的学术价值和实际应用价值.