Analysis of Spatial Stability of Long Span Steel Box Basket Handle Arch Bridge

With the increase of span length of basket handle arch bridge,the problem of spatial stability of the bridge becomes even more prominent.For analysis of the stability and the factors having influence on the stability of long span basket handle arch bridge,two methods of the linear buckling analysis and nonlinear buckling analysis may be used.The Chaoyang Rebuilt Bridge in Chongqing is a half-through steel box basket handle arch bridge with a main span 274 m.The linear elastic stability and geometric nonlinear stability of the structure are analyzed,using the spatial finite element models.The results of the analysis show that as the geometric nonlinear factors are taken into account,the 1st order stability coefficient of the structure apparently decreases and the influence of the geometric nonlinearity on the stability of the structure is apparent.The factors having influence on the global stability of the structure are also calculated and analyzed.The results of the calculation show that the influence of variations of the leaning angle of arch rib on the stability is great.As the leaning angle of the basket handle arch increases,the 1st order stability coefficient increases,however,the too big leaning angle will result in the torsional instability of the rib and as the rise-to-span ratio(width-to-span ratio) increases,the 1st order stability coefficient increases(decreases).The influence of the arrangement ways of lateral bracings and hangers on the stability of the structure is little.