The paper attacks the problem of steel redundant structures reliability. In calculations the probabilistic method of limit equilibrium is applied. All possible mechanisms of structural failure are considered. The influence of each section on the work of the frame as a whole is taken into account. Stochastic strength and load characteristics are used in the calculations. The proposed method of calculation allows to obtain structures with a given reliability. The calculation provides an opportunity to take into account the existing reserves of frames. The numerical example uses the logic of probabilistic transformations. The graphs of specific contributions of individual sections and the most probable mechanisms of destruction are presented. The probabilistic method takes into account the correlation between the individual mechanisms of destruction. The developed method determines the limiting moments, but it is allowed to take into account the action of the longitudinal force. In this example, the task was to align the impact of the frame sections without reducing the specified reliability, but it is possible to obtain a design with the same specific contributions, which is most economically justified. Specific contributions are increased or decreased as necessary to obtain a design with equal probability of failure. In the design, the influence of destruction individual mechanisms is used, because the cross sections of the beam span or floor column do not change from the design conditions. The method provides an opportunity to obtain more optimal designs and the use of modern software systems for static calculation. Recommendations for the design of these structures have been developed. It is proposed to use the reliability coefficient of redundant steel structures.

No abstract

No abstract

No abstract

The aim of the work is probabilistic calculation and evaluation of steel statically uncertain frames reliability parameters and recommendations development for reducing their material content by controlling the reserves of the load bearing capacity of the.A method for evaluating the reliability parameters of steel statically uncertain frames by all able-bodied statens is developed. Logical  probabilistic methods of statically uncertain systems work are used. The probability estimation method of statically uncertain systems failure based on the boundary equilibrium method, taking into account the correlation of individual destruction schemes, is obtained. The method of calculating the significance and contribution of individual frame elements and their influence on the system failure probability as a whole is proposed. The practical method of designing steel statically unidentified frames with the use of steel statically uncertain constructions reliability coefficient γs is offered. The scientific novelty of the work is to develop a scheme for determining frames failure probability by estimating the working capacity. In particular, the fragile and plastic fracturing failures of the frame section are considered. The algorithms for calculating the steel frames failure probability are determined by the probabilistic method of graphical equilibrium. The steel frame separate elements significance indexes are determined. The numerical experiment on the developed programs on a PC is presented for estimation of steel frames failure probability of various sections. the of of steel statically uncertain constructions reliability coefficient γs is proposed for usage.The practical value is more complete consideration of the structures and the probabilistic nature of strength and load, the use of the reliability coefficient. The possibilities of obtaining more economical frames in the design of new ones as well as reconstruction of existing buildings and facilities are identified. Based on the proposed methodology, algorithms and developed programs on the PC for the probabilistic calculation of steel statically uncertain frames for various purposes are compiled.