Study On Out-of Plane Stability Of High-strength Welded I-section Circular Steel Arch

The out-of plane stability of Q460 high-strength welded I-shaped steel circular arch was researched in this paper. The analytical models built by finite element software ANSYS first were compared to the tests result to verify the usability of the analytical method.First of all, the large deflection elastic-plastic finite element method, considering the geometric nonlinearity, material nonlinearity, were used to analyze the influence of parameters such as initial geometric imperfections, residual stress, ratio of rise and span and slenderness ratio on circular arch in-plane stability bearing capacity, to comprehend the main influence factors and regularity of steel circular arch.Secondly, Large deflection elastic-plastic finite element method were used to analyze the initial geometric imperfections and residual stress effect on the circular arch that bear axial compression force only. By comparing the Q235 common steel arch, the impact of steel strength grade on the overall stability of the circular arch under pure compression were analyzed. The results shows that compression stability coefficient of Q460 circular arches had greatly improved than that of Q235 in the normalized slenderness ratio coordinates. Combined with the column curves of codes for design of steel structure in China and Europe, the stability curve formula of Q460 high strength steel welded I-section circular arch is proposed and it has good accuracy and can be used for engineering use.At last, Large deflection elastic-plastic finite element method were used to analyze the effect of initial geometric imperfections, residual stress and moment gradient on the circular arch in bending only. By comparing the Q235 common steelarch, the impact of steel strength grade on the overall stability of the circular arch under pure moment were analyzed. The results shows that compression stability coefficient of Q460 circular arches had greatly improved than that of Q235 in the normalized slenderness ratio coordinates. Combined with the stability curve of bending straight beam proposed in ECCS code, the modified formula of Q460 high strength steel welded I-section circular arch is proposed and it has good accuracy and can be used for engineering use.