The Analysis On Optimum Structural Design Of Steel Trussed Arch Bridges

Steel trussed arch bridges have the advantage of grand and sublime externality, large-span power and strong carrying capacity. In the researching field of bridge engineering, people attach importance to the optimum structural design more and more, however, the application area and extent is not perfect, the theory of optimization based on the reliability is an important developmental one. For the question of the analysis on optimum structural design of steel trussed arch bridges, paper does work as following:(1) Based on a large quantity of reference, paper looks back the development of steel trussed arch bridges systematically, summarizes the existing research results of the optimum structural design and lists some problems, which should be studied further, aiming at the optimum structural design of steel trussed arch bridges based on the reliability theory.(2) On account of the structural style of deck type steel trussed arch bridges and mechanical characteristic of this type, paper builds model of the deck type steel trussed arch bridge by ANSYS.(3) With the secondary development APDL of ANSYS FEM software, paper makes the influence lines of the space structure come true, calculates the influence lines of the vertical deflection and axial stress in springing, l/8, l/4, 3l/8 and mid-span, and the most unfavorable position of load on the five points.(4) With the highway-I motor vehicle loading at the most unfavorable position of load of the five points, paper analyzes the characteristics of the bridge and checks the rigidity, the strength and the degree of stability.(5) Paper analyzes the dependability of bridge system with the motor vehicle loading, calculates the degree of reliability, analyzes the sensitivity on the degree of reliability of the steel trussed arch bridge and ascertains the reliability of every sectional dimension to the bridge as a result. (6) Paper restrains the bridge with maximal axial stress and maximal vertical deflection, defines the sectional dimension with larger sensitivity as design variables, aims at minimal own weight of the bridge. Paper ascertains the optimal alterative of sectional dimensions from the results taking into account of holistic and symmetrical loading response and checks the rigidity, the strength, the degree of stability.