The influence of an aggressive environment affects the appearance of physico-mechanical and physico-chemical corrosion processes, which in turn affects the depreciation of concrete properties, the redistribution of internal forces in sections and the depreciation of the working conditions of the reinforcement. The article discusses issues related to the degree of influence of environmental aggressiveness on building structures. It was shown that steel corrosion in concrete occurs due to a change in its passivity, which is associated with a decrease in alkalinity to pH <12 during carbonation of concrete. Data on the average rate of destruction of the material (metal and concrete) are given in case of corrosion. Types of solutions to extend the life of buildings and structures are presented. Methods for calculating physical wear are highlighted. The physical depreciation of the building is shown graphically, considering repair work. The definition of physical depreciation of buildings based on the calculation of the physical depreciations of its individual structural elements is given. An example of calculating the physical depreciation of a building is considered. A formula has been developed for determining the degree of damage to structural elements of a building object. The results of calculations of the degree of damage and the degree of physical depreciation of structural elements of the building are presented.

An algorithm has been developed to optimize the reinforced concrete beams in removing the supports based on an adapted genetic algorithm and RBDO approach. Multiple cross-sectional dimensions of elements, concrete class, class and diameter of the reinforcements vary. Avoiding significant changes in the geometry of the structure after emergency actions is considered as the main active constraints. It is believed that this constraints provides the required structural resistibility in an emergency situation. The value terms of material losses risk in case of a possible structure failure as a component of the objective function is considered. The proposed genetic algorithm includes an adapted mutation operator and the elitism strategy for selecting the best solutions. The algorithm presented allows obtaining design solutions of high operational reliability for rectangular reinforced concrete beams, taking into account the optimal ratio of a structure costs and the risks of its failure in an accident.

MATEC Web of Conferences, open access proceedings in Materials science, Engineering and Chemistry

The article is devoted to improving the calculation of reinforced concrete slabs, taking into account the deformation under prolonged load and spatial design work. As a reference for the calculation of the impact study is taken shape, size and location of the holes in the circuit boards of fracture, as well as the proposed expression for calculation of deflections for one of the cases. Use of the deformed scheme allows to develop a settlement unit, approximating to the actual calculation of the plates, as well as to achieve a significant reduction in materials. We consider the continuous slab, supported on a loop and a plate having a square hole in the center. For practical basis for calculating the deflection plates, it was created in the design scheme of the complex system Ing + Gen_3dim 2014.

This article provides an example of the calculation of eccentrically compressed reinforced concrete elements operating under dynamic loads and fire effects. Dynamic coefficient depending on temperature and strain rate, the results of experiment varies widely from 0.4 to 0.8. It is possible to reveal the influence of the dynamic effect on the reduction of the bearing capacity of the pylon and fire and columns of 40%.

Some examples of failures of structures, buildings, where the lack of robustness was recognized, are analyzed. Several author’s definitions for robustness are presented and discussed. Special emphasis is given to the fact that define robustness as an intrinsic structural property and the other hand it as a property of the structure and its environment. Some related concepts are presented and discussed.The most important proposed measures for robustness are also present-ed including some illustration examples. Finally, a comparison between them is made and the respective shortcomings are identified. After anal-ysis of the robustness nature, a new structural oriented definition is pro-posed. Based on the highlighted shortcomings of the existing measures, in particular those related with the application to deteriorated structures, a conceptual framework for robustness assessment is proposed.