This paper deals with the study of stochastic parameters of external loads, which are used in the tasks of determining the level of reliability of steel storage capacities. To describe the random load process, the normal law and the double exponential distribution of Gumbel were used. It was formulated the technique of transition from the study of the entire random process to the consideration of its maximums. It was obtained quantitative values of the stochastic characteristics of snow and wind loads on the territory of Ukraine, without reference to the zoning maps. A general procedure for determining the probability of failure was formulated, depending from a given characteristic maximum. This index corresponds to the basic level of load. The average intersection of this level by a random load process is equal to one. Analytical formulas are obtained to determine the scale and position of the double exponential distribution of Gumbel, which depend on the characteristic maximum, as well as formulas, which help to calculate the statistical characteristics (standard, expected value and coefficient of variation) of the random value of the load maximums. The possibility of using this approach is theoretically confirmed when the density distribution of the ordinate of a random process follows the normal law. It was proposed expressions for the parameters of the distribution maximums of the random processes, which are described by the polynomial exponent and the Weibull law.

The paper deals with the features of silos calculations as shells of rotation under asymmetric semi-uniform load. In accordance with the equation of equilibrium by using the momentless theory, the expressions for maximum value of linear longitudinal efforts in radial and meridional (longitudinal) direction and linear shearing force have been obtained. Analysis of design factor series of linear efforts and shearing force has been carried out in the paper. The opportunity of using the momentless theory to evaluate changes of linear efforts in radial direction and shearing forces has been presented. The quantitative assessment of a normal tension in laminas of silo body from the influence of maximum linear efforts and their connection with the tension from the pressure of the bulk material at the top of the capacity have been given. Full radial and contacting displacements of the capacity in the plane of cross section from the element of the wind load have been defined.

The article is devoted to the study of geometric characteristics of corrugated sheets of railway grain hopper. In particular, the problem of finding the optimal parameters of a corrugated sheet of a given length, such as the height and width of the corrugation shelves, is solved. The optimality condition in this problem is determined by the minimum mass of the corrugated sheet. Because of analytical calculations, it was found that, regardless of the angle of tip of the corrugation wall, there will always be such a value of optimum height at which the corrugation area will be the smallest. For the analysis of this parameter, a series of curves of dependence of the corrugation cross-section area on the height for different angles of tip were constructed. The study also provided concise and engineering-friendly equations to determine the optimum height and width of corrugation shelves for wall angles up to 60º. These expressions can be applied to the case of corrugated sheet with a limited number of erection joints. For other cases of jointing of the corrugated sheets with each other (complete or partial overlapping of the lower part), additional studies should be performed similar to the procedure presented.

This paper deals with the investigation of work of the vertical steel cylindrical storage silos for grain with the different thickness of casing sheets and stiffeners at different height sunder the asymmetric wind load. Construction is designed using the analytical method involving decomposition of load into the completed trigonometric series and adding separate stress-strain states of k influence. The construction design model is a thin-walled cylindrical shell reinforced with vertical stiffeners. According to the shell theory, all unknown elements of the stress-strain states from the wind load components are expressed by unknown function ξk (x). In the analysis, the introduced hypotheses were used, which provides for using exponential dependence to describe the thickness changing law of the casing sheets and stiffeners and the equality of the change rate of these characteristics. The obtained results for silos with corrugated wall showed that the desired function which characterizes the stress-strain state of the construction is determined by ratio of the total cross-section area of all stiffeners to the cross-sectional area of the silo provided this ratio is constant at all heights. Represented calculation formulas for radial, circular and longitudinal displacements, and for strains in cross-sections are simple enough for using in the engineering practice.

No abstract