Mechanical Properties Research On Wide Deck City Bridge With Leaning Tied-Arch Using CFST

Leaning concrete filled steel tube arch is a type of complicated spatial bridge, it is a space force system which is consisted of two vertical main arches in the middle and two inclined arches. In this system, the main force structure include main arches, inclined arches, steel box girders and main girders, the others are all secondary structures. Under the influence of live loads, the loads from motor way and parts of super way and sidewalks were born by main arches, then horizontal loads were delivered to main girders to form a arch bridge without thrust at supports. Main arches and inclined arches are connected by lateral ties to form an entirety with strong lateral stiffness and good stability. Such bridge is suitable for city bridges with higher requirements of landscape and wider deck.Based on the preliminary design of Guiyang Road Twelve Nanming Bridge, the leaning concrete filled steel tube arch was researched and analyzed. First of all, full bridge finite element model was established using MIDAS/Civil software to analyze the static performance of main force components of leaning CFST arch in the construction stage and operational stage. Factors such as span ratio, arch beam stiffness ratio, structural system were studied. The dynamic performance and stable performance of the bridge were analyzed, especially the stability of the bridge in the construction stage and operational stage were researched. The influence rule of some parameters such as the dip angles of main arches and inclined arches, the stiffness of lateral beams, the number and location of lateral beams, structural system and construction sequences on spatial stability of leaning CFST arch. In the preliminary design of the bridge, the CFST arch was designed as a two-hinged arch, in which the arch hinge was with cylindrical contact surface to make it consolidated at first and then articulated during the construction process, the locality of arch hinge with complex structure and force belonged to contact problem. The local stress of the hinge using common software ANSYS were analyzed and were compared with the theoretical results calculated by Hertz. After that the mechanical properties of cylindrical hinge were compared with spherical hinge under dead load axis force. The influence of different radius of the hinge on mechanical performance was analyzed, according to the results some reasonable measures were came up with.The results indicates that the internal force, dynamic characteristics and stability characteristics of leaning arch entirely meet regulatory requirements, the result of second method also indicates this kind of hinge totally meets the require of the structure and the bearing capacity. The mechanical properties of leaning CFST arch were analyzed comprehensively, and the influence of this type arch on force characteristics and parameters were summarized. Preliminary references and suggestions for the design of leaning concrete filled steel tube arch were provided.