Research On The Stability, Static And Dynamic Characteristics Of The Steel Truss Beam And Flexible Arch Bridge

First of all, the development situation and structure characteristics of the steel truss beam and flexible arch bridge is briefly introduced, due to it has beautiful and lightsome, strong spanning ability, flexible construction methods and material utilization rate higher characteristics, in recent years, it developed rapidly in railway bridges in our country. However, the scholar’s understanding of the steel truss beam and flexible arch bridge both in theory and practice is not comprehensive enough, the research data for the study of it currently is rarely informed. The large finite element software Midas Civil 2012 which can establish the finite element model of the whole bridge is used in the paper, Nanping Bridge is taken as the engineering background, according to the basic theory and the general steps of the finite element modeling, The analysis and research on the design scheme of double rigid truss beam flexible arch bridge with the span of 48+120+48m is mainly about the static performance, dynamic characteristic and full bridge stability aspect.Six kinds of load including dead load, moving load, temperature load, wind load and so on were taken as the necessary loading factors to analyze mechanical properties of the steel truss beam and flexible arch bridge. As for dynamic property, natural vibration period and model of vibration of bridge under completed phase were studied based on subspace iteration method. Parameter sensitivity analysis was also carried out to state the dynamic property of structure composed of rigid girders and flexible arch. It is summarized that the basic types of stability problems, the main unstable form of arch bridge and the method of calculating the instability in the paper, the elastic stability of Nanping Bridge was studied by using finite element method, and the influence factors of stability were analyzed, the paper mainly study the influence of the local bars(vertical web member, oblique web member) stiffness failure on full bridge stable performance, to find out the influence on the stability of the key web member, and analysis the key web member stiffness change on full bridge stable performance, discuss the structure as a whole bar(vertical web member, oblique abdominal member, deck transverse contact, arch rib) rigidity change stability safety coefficient of variation trend and the corresponding buckling mode, and the influence degree of the overall stability of the whole bridge is calculated. Finally, the influence of the change of the structure design parameters(the form of the arch rib and the width span ratio) on the stability of the whole bridge is studied.Mechanical characteristic of the steel truss beam and flexible arch bridges were summarized systematically and key points of calculation on these bridges were mastered. The static, dynamic characteristics and stability of the bridge structure are fully understood, so as to provide reference for the design and construction of the bridge with the same structural characteristics.