The possibility of further trouble-free operation of existing buildings and structures is determined by their technical inspection. The task of assessing the technical condition of an object is directly related to the determination of the wear of individual structural elements and the entire structure as a whole. To solve this problem, it is necessary to establish how the operability of a particular element of a building affects the operability of a building as a whole. This can be done by introducing the notion of the significance of individual constructive elements. The authors consider the variants of practical methods used to determine the coefficient of significance of constructive elements, compare them and propose to use a metрod based on the definition of the entropy of the system. An example is given of determining the significance coefficients of structural elements for an industrial building.

The purpose of this work was to identify the main problems associated with their compliance. Experimental studies of the strength of such elements. It turned out that, before the compression of the concrete core and the placement of a high-strength longitudinal reinforcement in it, it was possible to obtain a breakthrough of the investigated samples. Strength of improved samples compared with pipe-type samples of the classical design increased by 30 ÷ 50%. The above formulas are applicable for calculating the strength of both pre-compressed and uncompressed pipe-concrete elements.

The influence of the form of the functional dependence of the stresses on deformations on the accuracy of determining the deflections of a plate from a nonlinearly deformed material is investigated. The requirements that must be fulfilled when choosing an analytic expression for the description of the functional dependence "σ-ε" are established. According to experimental data, it is established that the basic building materials have nonlinearly deformed deformation diagrams. Linear, power, parabolic, hyperbolic, exponential, trigonometric functions used to describe the deformation diagrams of cement concrete under compression are considered. Graphical and numerical data indicate that analytical functions describe the experimental "σ-ε" diagram with sufficient accuracy. It is shown that the basic physical parameters that determine the physical nonlinearity of the concrete deformation diagrams are the temporary resistance, the modulus of elasticity and the relative deformation corresponding to the temporary resistance of concrete.

For many materials there is a correlation between the area, that determines the crack growth, and the size of the material structure, obtained on the basis of the theory of dimensions. During the study of the fracture surface the connection between profilogram’s parameters (taken from the sample fracture surface on a cement binder) and the material structure has been detected. Series of experiments shows, that the profilograms (taken from the fracture surface, that has been formed from stretching and processed by cellular methods) are described by fractal geometry methods. Мoreover the value of the fractal dimension of the profilogram is related with the tensile stress gradient.

Now the radon flux density from soil surface is the only criterion for the radon hazard of construction site. However, the radon flux density determination at the environmental surveys stage does not provide initial data for the design of buildings radon protection. In such conditions, a fundamentally new methodology is needed to ensure the buildings radon safety at the design stage, which based on the unified media system “soil-atmosphere-building” consideration. The paper proposes an approach to determining the required radon-protective properties of a building on the basis of an analysis the soil characteristics and building underground part construction. This approach not only takes into account the construction site radiation and geological characteristic, but also allows the selection of optimal design solutions for underground walling. Its use will reduce the cost of engineering and environmental research and avoid the buildings with excess or insufficient radon-protective properties commissioning.

Sound insulation of the multilayered interfloor overlappings is considered. It possesses the best technical and economic indicators than traditional overlappings with floors on elastic laying. Theoretical researches of isolation of shock noise are executed. It is established that in the low frequency region multilayer overlaps have high sound insulation properties and lead to a decrease in the level of shock noise by about 24 dB at each frequency doubling. The lowest value of shock noise isolation is achieved in the frequency bands corresponding to the second frequency of the floor eigenfrequencies. In the mid-to high-frequency region, the increase in additional shock noise isolation under multi-layer overlap slows down to 12 dB per octave. The experimental inspection of the received conclusions is carried out. The comparison of calculated and measured frequency characteristics of the impact noise reduction showed a good agreement between the results of theoretical and experimental studies. It is shown that at the same surface density multilayer structures of overlappings better isolate shock and air noise than traditional structures of floors with elastic pads.

In this article, various versions of air conditioning systems are considered, including heating and ventilation in the existing Orthodox churches in Crimea. Based on the studies carried out at these sites, which included a field survey and numerical measurements, it was found that the provision of a regulatory temperature and humidity regime is not carried out and faces a number of difficulties that require correct intervention. For this solution, it is necessary to determine the main sources of the violation of the temperature and humidity balance in the volume of the temple and to assess the efficiency of the climate systems in creating an optimal microclimate inside the building.

The estimation of the minimum required accuracy of calculations of temperature fields is carried out. Two main cases are distinguished. It is shown that the calculation of the reduced heat transfer resistance and specific heat loss is most sensitive to the accuracy of the temperature distribution. The source of error in mathematical transformations, which must be eliminated by the correct choice of the computational grid step, is given. The examples illustrate the features of calculations of temperature fields of enclosing structures. Errors in the choice of the computational grid for the finite difference method leading to unsatisfactory accuracy of calculations are shown. Recommendations are given to improve the accuracy of calculations for stationary and non-stationary cases. Examples of the influence of the computational grid step on the error of temperature and heat flow determination are considered. Examples of overestimation of accuracy in regulatory documents leading to false expectations of designers and experts are given.

The specific characteristic of the heat energy consumption for heating and ventilation which is the key indicator of the energy consumption of the building is considered. The factors considered in the calculation of energy consumption in earlier regulatory documents are shown. The main realized directions for improving the calculation of energy consumption in the current normative document SP 50.13330.2012 are shown. The basic directions of improvement of the considered calculation in the prepared Change No. 1 to the SP 50.13330.2012 are presented. The balance of supply and exhaust ventilation air for flats of residential buildings has been analyzed. The factor is revealed that is one of the most important reasons for underestimating of the evaluation of energy consumption for heating and ventilation. Recommendations are given for the main directions of the subsequent modernization of the calculation of specific ventilation characteristic within existing technological possibilities.

In the sanitary-hygienic assessment of the noise regime in places where people stay in masses, the sound levels determined in decibels A are used. The paper proposes a simplified technique for calculating sound levels in decibels A, generated by speech in places of mass congestion. The technique allows to significantly increase the speed of calculation of sound levels. The article specifies the limits of its application. Calculation of the sound levels of the speech of a congestion of people can be made directly in decibels A. This makes it possible to increase the speed of calculations by almost 8 times. The errors in the calculation of sound levels in decibels A, according to the proposed method, depend on the characteristics of the sound-absorbing properties of the enclosures. Errors are minimal in the case of low dependence of the noise absorption coefficients of fences on frequency, which is typical for most surfaces of enclosure fencing. The exception is made by sound-absorbing structures, the spectral characteristic of sound absorption of which varies greatly depending on the frequency of sound. When using such structures, it is necessary to perform calculations for all regulatory frequency bands.

To solve the problem of estimating the quality of composite building materials, it is proposed to use the method of multi-criteria comparative analysis. Several variants of compositions of the mixtures of composite building materials with the use of cement bonded particle board waste are considered, each of them is characterized by a certain set of properties - evaluation criteria. To determine the best variant of the composition, according to the evaluation criteria in question, it is possible to use weighting coefficients, reflecting the significance of a particular property. Practical use of the multi-criteria analysis method for the technical and economic estimate of composite materials allowed, with setting certain priorities, to perform the ranking of compositions with a single synthetic index. The proposed method of estimating quality can save time of searching for the optimal variant significantly and increase the objectivity of the estimate.

The measures of the creep of high-strength steel fiber concrete and the matrix of fine-grained high-strength concrete have been determined for different ages of loading (7 days, 28 days and 100 days) on the basis of elaboration of the experimental method applied to various levels of load. The correction of the formula of Prokopovich I. E. and Zastava M. M. to describe the linear creep measure applied to a new class of fine-grained high-strength concrete and steel-fiber concrete; the development of the experimental method of Prokopovich I. E. and Zastava M. M. in the case of determining the nonlinear creep measures for a new class of MVB and VSFB. The proposed dependence for the description of creep measures agrees well with the experimental data.

To increase the efficiency of reinforced concrete structures and increase the strength characteristics, discrete fibers (fibers) of various origins are introduced into the concrete composition. When calculating reinforced concrete structures for fire resistance, it is necessary to know the thermal physical characteristics of concrete.The paper presents the results of the experimental determination of the thermal conductivity and specific heat of specimens made of steel fiber-reinforced concrete with steel wire wavy fiber, depending on the percentage of fiber content in volume 1.5; 3.0 and 6.0%. The samples of the matrix (fiber content 0%) were also tested. A technique and a formula for determining the specific heat of steel-fiber-concrete samples using contact temperature recorders are proposed.The results of the research showed that the coefficient of thermal conductivity and the specific heat of steel fiber-reinforced concrete depend on the percentage of fiber and decrease with increasing percentage of fiber content by volume.