Behavior of bearing reinforced concrete panels in the process of combined action

This research of has important significance in the constructive solution, manufacturing technology and labour costs. The irreversible changes in mechanical properties occur in reinforced concrete elements, decrease in compressive and tensile strength, additional deflections. In this paper, the goal was to assess the behavior of the bearing reinforced concrete panels with a combined action (fire and force) as close as possible to the actual effect in a fire. It was necessary to solve the following tasks: to determine the dependence of deflection and deflection rate on the heating of the plate and the load acting on the panel, to determine the amount of concrete falling before breaking the integrity of the panel (the formation of through cracks, determine the degree of heating of the panel from the duration of fire and force

Conceptual problems of high-rise construction and differentiation of research within the urban environment system

The subject of this article is increased growth of the city construction with high-rise buildings of different functions. It is possible to distinguish two periods: the period of the differentiated participation of representatives from various fields of knowledge, characterized by traditional approaches and methods of each of the fields of science, and the period of integration of cross-disciplinary research, characterized by general understanding of the city as the complicated system. With respect to the system approach it is possible to distinguish several levels of hierarchy of the subsystems forming the urban environment, which provides the implementation of needs of a person and requirements of the state economy for the effective development of natural wealth and human resources. Chambers or groups of chambers, which are functionally connected depending on the way of their use in the daily cycle of multifunctional architectural – planning complex maintenance, are subdivided into four groups; each of them correspond to a special type of accumulation and movement of human flows. The analysis of movement dynamics of «entrance-exit» human flows in buildings of various types is presented. The given regularities of time dynamics of the urban population attendance of enterprise of various groups are described in the article. The lack of the aforesaid dependences, as well as the lack of necessary input data results in the inefficient project solutions, their adjustment during the maintenance requires considerable economic-and-organizational costs otherwise it is impossible in practice

Improving Fire Protection of Pontoon Tanks or Floating Roof Tanks

The paper presents research of new solutions to improve fire protection of pontoon tanks or floating roof tanks. Extinguishing efficiency of the subsurface supply system is boosted by a different configuration of the pontoon or floating roof, and also with a cooling system used for oil product evacuation. Efficiency of the proposed methods is more than doubled compared to the existing subsurface extinguishing method

The consideration of the turbulence influence on the gas explosion expansion in non-closed areas

In the gas explosions simulation practice in non-closed areas there is a common opinion of burning rate increase at turbulization of initial gas mixture stream. The article shows that in conditions of turbulization there is no increase of the burn rate, but of the flame front area. A wording change of pressure rise reason does not lead to a change of the calculation results, but gives the opportunity to look at the problem differently and interpret a physical process correctly. In order to prove it there are results of the vibrational combustion modeling in terms of gas explosion in the cylinder with an opening on the side. The results show that along with the pressure fluctuation there is burning area size fluctuation that occur synchronous and with the same amplitude. The modeling basis is the system of differential equations, that describe the adopted in gas dynamics fundamental conservation laws, the equation of state, written in the so-called Euler’s form. The system is supplemented with flame spread conditions. The system solution is based on the Russian method of the numerical approximation of this system-the large-particle method

Improving Fire Protection of Pontoon Tanks or Floating Roof Tanks

The paper presents research of new solutions to improve fire protection of pontoon tanks or floating roof tanks. Extinguishing efficiency of the subsurface supply system is boosted by a different configuration of the pontoon or floating roof, and also with a cooling system used for oil product evacuation. Efficiency of the proposed methods is more than doubled compared to the existing subsurface extinguishing method

Conceptual problems of high-rise construction and differentiation of research within the urban environment system

The subject of this article is increased growth of the city construction with high-rise buildings of different functions. It is possible to distinguish two periods: the period of the differentiated participation of representatives from various fields of knowledge, characterized by traditional approaches and methods of each of the fields of science, and the period of integration of cross-disciplinary research, characterized by general understanding of the city as the complicated system. With respect to the system approach it is possible to distinguish several levels of hierarchy of the subsystems forming the urban environment, which provides the implementation of needs of a person and requirements of the state economy for the effective development of natural wealth and human resources. Chambers or groups of chambers, which are functionally connected depending on the way of their use in the daily cycle of multifunctional architectural – planning complex maintenance, are subdivided into four groups; each of them correspond to a special type of accumulation and movement of human flows. The analysis of movement dynamics of «entrance-exit» human flows in buildings of various types is presented. The given regularities of time dynamics of the urban population attendance of enterprise of various groups are described in the article. The lack of the aforesaid dependences, as well as the lack of necessary input data results in the inefficient project solutions, their adjustment during the maintenance requires considerable economic-and-organizational costs otherwise it is impossible in practice

Experimental Evaluation of Fire Resistance Limits for Steel Constructions with Fire-Retardant Coatings at Various Fire Conditions

The experimental evaluation of fire resistance limits for steel constructions with fire-retardant coatings consists of a lot of experiments on the heating of steel structures of buildings by solving a heat engineering problem at various fire conditions. Building design implies the assessment of compliance of actual fire resistance limits for steel constructions with the required limits. Fire resistance limits for steel constructions are determined for “standard” temperature mode, and this can lead to overestimated fire resistance and underestimated heat influence for a real fire. Estimation of the convergence for “standard” temperature mode and possible “real” fire mode, as well as of the compliance of actual fire resistance limits with real fire conditions, was realized in the following stages: mathematical modeling of real fire development by the field model in software package Fire Dynamics Simulation (FDS) with various fire loads and mathematical modeling of steel construction heating for the standard temperature mode obtained by modeling “real” fire modes (the finite difference method of solving the Fourier heat conduction equation at external and internal nonlinearities was used for modeling the process of steel structure heating with the implementation in the ANSYS mechanical software package). Experiments of the assessment of fire-protective paint’s effectiveness were carried out for standard temperature mode and obtained by modeling “real” fire modes. The equivalent fire duration dependence on fire load type was determined. This dependence can be taken into account in determination of fire resistance limits for steel constructions in warehouse building roofing. Fire-protective paint effectiveness was estimated for “standard” temperature mode and various other temperature modes

Problems of the dynamic test method for individual protection equipment (shock absorbers)

This paper examines issues of safety of high-altitude works, using individual protection equipment to prevent falling from a height. In particular, the paper reviews personal protective equipment - shock absorber, its dynamic characteristics and related test methods to meet the requirements of Technical Regulations 019/2011 “Safety of Individual Protection Equipment”. The paper discusses the differences between the Russian and European standards for dynamic characteristic testing of shock absorbers, even as the former are harmonized texts of the latter, and the effect of such differences on protective performance of shock absorbers and ultimately on safety of works on heights. It have been shown that tests, conducted in accordance with the Russian regulative documents for dynamic performance of the shock absorbers, entail decreasing in safety usage of such type of IPE and increasing in injuries during falls from a height. It has been defined necessity to actualize the range of the testing system of shock absorbers, and to admit its larger value that will cause increase in protective properties of shock absorbers

Efficiency evaluation criteria of communication paths structure in a complex of buildings of maternity and child-care institutions

The communication paths form the network of areas that connect the public spaces of the building among themselves and with external (in relation to the building) sources and accumulators of crowd flows. The spaces can have different purposes of use. The function of the communication paths is always the same – ensuring the safe movement of crowd flows. That’s why communication paths are one of the security systems of buildings, constructions and associated areas under various application conditions. The areas of communication path can be different types: horizontal, stairs down, stairs up, ramps, openings. Its effective size is determined in accordance with values of crowd flow movements. They can vary depending on numerous factors, but represent the result of invariant patterns of connection between parameters of flows which have different composition. The article considers the calculated values which determine the criteria of optimality of the size of communication paths of buildings using the buildings of maternity and child-care institutions in their multifunctional use as an example