Research of change stiffness function of cross section round arch of welded i-section

Purpose. Search rational cross-sectional shape of arch structures of welded I-sections remains uncharted theme and has a number of tasks requiring clarifications and further research. These tasks have estimated: the effect of combinations of loads on the search for a rational function changes the stiffness of arch design of welded I -sections described the circle function. In addition, it is a search for a rational section, in terms of costs of steel, for each point of the arch, and the structural features encountered in the design of the arches of variable stiffness. The purpose of the article is define the types of loads that have a major impact on the distribution of forces in the round arches. In addition, it is obtain the distribution function of bending moments and longitudinal compressive force by various combinations of loads. At last, it is the establishment of the function changes the stiffness of the arch to the arc length. Methods. Methodology for solving the problems of numerical studies has conducted in the program complex "LiraCAD 2013 ACADEMIC Set?, as well as analyzes of functions distribution efforts and changes in the stiffness of the cross section along the length of the arch. Results. The types of loads that have a major impact on the distribution of the maximum effort in the round arches. Shows the search procedure of stiffness changes obtained by the function of the arch length of action maximum design load combinations. Presents options for the possible design solutions arches of variable stiffness. Scientific novelty. Shows changes the stiffness of the arch, which allows the rational design using different variants of design solutions in the field reducing section. These examples the stiffness changes in the upper third of arches which are not only economic and technically feasible in terms of manufacture and mounting frame diameters, but such that the expression does not violate architectural and building construction in general. The practical significance. Presents design solutions arches of variable stiffness and point placing assemblies of the constituent elements of the arch. Developed the method of searching for optimal cost of steel constructions of round arches of variable stiffness of welded I-beams, which opens the way to further development of the theoretical approaches and the design of this type of structures.