Vol 15, No 3 (2019)

Introduction. Prospective transition of CIS to the European design standards in the construction industry requires development of new and modification of known engineering methods for calculation and design of construction. Creation and development of such methods should be based on fundamental research that can become the basis for the development of principally new, innovative technologies. Methods. The paper consists of basis and practical application of the method of full discretization. This method is a special modification of finite element method for the solving of problems of the creep. Practical application of the method is illustrated with modeling and applied tasks. Results. The paper presents a joint calculation of the “structure - foundation - soil” system using the example of a reservoir of a modular biological wastewater treatment plant designed for filtration fields in the village of Tasboget, Akmola region, the Republic of Kazakhstan. The full picture of the evolution of the stress-strain state of structures is gained, taking into account the material creep and the history of construction. There is a comparison of result calculations with and without technology of erection of structures.

The aim of the research is to numerically determine the effect of wind loads on the roof of the rolled profiles of the MIC-120 system. Methods. There were made some calculations in this article of wind load, acting on rolled metal thin-sheet profiles arch and a comparison of computer modeling and buildings requirement such as Building Rules “Loads and Actions” results. The research was carried out by means of modeling of a virtual wind tunnel with the placement to it a metal thin-sheet profiles arch in consideration of different wind actions such as acting on the arch’s butt end (along a generatrix), as well as athwart on the arch and angularly on it with the arch’s width change from 12 to 24 m. The arch modeling as well as the virtual wind tunnel modeling was based on the COSMOSFloWorks software package by means of the method, stated in the previous publications [2; 11]. The theoretical and methodological basis of the research is the Navier - Stokes equation and the equation of the condition of the fluid medium’s components. Results. The results are, first of all, the calculation of the wind pressure on the arch depending on the trajectory, wind speed in different regions and directions of wind flow, secondly, the comparison of the wind pressure, getting with the help of computer modeling with Building Rules 20.13330.2011 “Loads and Actions” and, finally, matching of results of wind pressure for a plain and ribbed arch with equal geometrical parameters, getting by computer modeling. In compliance with the generated calculations there was drawn a conclusion, that the standard pressure according on Building Rules does not change from arch span, but results of the computer modeling show us a change of the wind pressure from the arch’s span.

Introduction. Optimization is a criterion, on the ground of which, comparative estimation of possible alternatives and selection of the best decisions is carried out. Cost of a shell, its minimum weight, absence of bending moments and tensile normal stresses, given stress state for acting external load, given bearing capacity when optimal shallowness, maximum external load, minimum weight under limitation on the value of natural frequencies of vibration and maximum displacements, absence of bending moments with taking into account internal pressure, dead weight, and centrifugal forces; maximum of critical force and something else can be criterion of selection of optimal shape of shell of revolution. Methods. The main criteria of optimality for shells of revolution and information sources for the 1970-2019 periods are presented in a paper. It will help to study previous results devoted to using optimizations and to set about further investigation. But there is no single approach to the definition of optimal shell of revolution and obviously will not be, because own optimizations are necessary for every concrete case of loading, or distribution of stresses along the thickness, or under the demands to the ratio of the volume and area of considered shell, or with due regard for different kind of expenses, and other demands. Results. For the first time, 24 criteria of optimality only for shells of revolution were discovered. The names of scientists offered presented criteria of optimality and the 45 references dealing with this question are pointed out. It is shown that principles put in the basis of optimal design and criteria of optimality must be given with the help of language quite naturally for computer. Having used optimi- For citation Krivoshapko S.N. (2019). Optimal shells of revolution and main optimizations. Structural Mechanics of Engineering Constructions and Buildings, 15 (3), 201-209. http://dx.doi.org/ 10.22363/1815-5235-2019-15-3-201-209 zations presented in the paper, designers can choose the criterion for their own design of optimal shell shape. Study of the prerequisites of the structural solutions in building and machine-building, the history of the development and perfecting of technologies of erection of shells of revolution will permit to generalize the experience accumulated by designers and to develop new fundamental solutions. Otherwise, architects, structural engineers, and designers will be repeating the achieved solutions in building, architecture, and machine-building.

Aims of research. Research and analysis assessing the risk of hazards (in particular earthquake hazardous) at hazardous industrial and classified sites industry. Methods: analytical, mathematical, operational-tactical, mechanical-statistical, study of deformation of seismic diaphragms. The analysis of risk through seismologist at hazardous production facilities of the industry in conjunction with the secondary fires. This circumstance, which often coincides with the joint vector, is proposed to be used as a mechanism to ensure the safety of industrial facilities from seismic fire hazard, including aspiration flows as an impact factor. Risk analysis is viewed taking into account the algorithm to ensure the safety of complex technical and social systems, which shows the degree of universality of the algorithm. This security mechanism is most important to take into account for architectural General plans of buildings and structures, as well as in operational and tactical actions of units in the aftermath of emergencies, crisis and extreme events. Results. The analysis is accompanied by the necessary mathematical calculations and experimental assessments of the security process.

Relevance. During the operation process (first of all, long-term operation) of hydraulic structures, it becomes necessary to strengthen their reinforced concrete structures. In recent years, reinforcement of reinforced concrete structures has been used in industrial and civil construction by external reinforcement systems made of composite materials (for example, carbon materials). In this case, in hydraulic engineering construction there are only isolated examples of such amplification. Aims of research. Experimental studies of reinforced concrete structures of hydraulic structures strengthened with external reinforcement from carbon materials presented in the article were carried out in order to substantiate the use of external reinforcement based on carbon materials (tapes and lamellae) to reinforce reinforced concrete structures of hydraulic structures. Methods. In order to carry out an experimental study of the strengthening of hydraulic structures with external reinforcement, reinforced concrete models of hydraulic structures of a beam type were made of carbon materials. At the same time, reinforced concrete structures with characteristic features of hydraulic structures, such as low concrete classes and reinforcement percentages (less than 1%), were adopted for modeling. Reinforced concrete models were strengthened with carbon ribbons and lamellae. Experimental studies were carried out under the action of a bending moment using standard methods. The increase in the strength of reinforced concrete structures due to their reinforcement with carbon ribbons and lamellae was determined. Results. The results of experimental studies of the strength of reinforced concrete structures of hydraulic structures without reinforcement and reinforced with carbon ribbons and lamellae under the action of a bending moment are presented. On the basis of the comparison carried out, the increase in the strength of reinforced concrete structures is determined by their reinforcement with carbon ribbons and lamellae.