哑铃型钢管混凝土拱肋极限承载力研究

为了研究哑铃型钢管混凝土拱肋的力学性能,基于统一强度理论和等效梁柱法,考虑中间主应力和材料拉压比的影响,推导了其极限承载力的新公式。采用梁单元建立哑铃型钢管混凝土拱肋的有限元模型,对其受力全过程进行双重非线性分析。将理论分析结果和数值计算结果与相关文献的试验结果进行比较,吻合良好,验证了本文理论分析方法和有限元计算方法的正确性。采用有限元方法,对荷载工况、长细比、矢跨比、截面形式和腹腔混凝土等参数的影响特性进行分析,研究结果表明,荷载工况对哑铃型钢管混凝土拱肋的极限承载力影响显著,荷载越对称、均匀,拱肋的极限承载力越高,竖向变形越小;拱肋的极限承载力随长细比的增大而显著降低,随矢跨比的增大先提高后略有降低;截面形式对拱肋的强度和刚度均有较大影响,而腹腔混凝土对其强度和刚度几乎没有影响。

Study on ultimate bearing capacity of dumbbell shaped concrete filled steel tubular arch rib

To study the mechanical properties of dumbbell shaped concrete filled steel tubular(CFST) arch rib,a new formula of ultimate bearing capacity was deduced according to unified strength theory and equivalent beam-column method,considering the impacts of the intermediate principal stress and tension-compression ratio of materials.Additionally,the finite element model of dumbbell shaped CFST arch rib was established by using beam element and the whole loading progress was analyzed with consideration of both geometrical and material nonlinearities.Through comparing the theoretical analysis results and numerical simulation ones with those of experiments in the related literature,the validity of the method is proved.Moreover,influencing characteristics of such factors as load cases,slenderness ratio,rise-span ratio,section types and concrete filled in web space were studied by using finite element method.The results show that:the load cases have significant influence on the ultimate bearing capacity of dumbbell shaped CFST arch rib;the more symmetric and uniform the load is,the higher the bearing capacity is,the smaller the vertical displacement is.The ultimate bearing capacity of arch ribs decreases significantly with the rise of slenderness ratio,and increases at first and then decreases slightly with the growth of rise-span ratio.The section types have great impact on both strength and stiffness of arch ribs,while the concrete in web space has little effect.