Introduction. In order to give geometric immutability to load-bearing structures that accept horizontal loads from the wind, it is necessary to introduce rigid nodes into the design scheme. The insufficiency of the regulatory framework for calculating nodes with glued joints leads to a separation of calculations from company to company. This paper proposes a method for designing and calculating a ridge assembly of wooden structures with glued washers.

Materials and methods. Engineering calculation of the ridge node and its elements, modelling and calculation of the considered connection, as well as analysis of the possibility of its application on the example of an existing building, calculated in the SCAD software.

Results. A constructive solution for a new type of rigid assembly was developed based on the use of steel washers glued into wood. A numerical and theoretical analysis of each element of the joint for the forces transmitted by neighboring structures is carried out. Estimation of the numerical order of the bending moment perceived by the proposed design. The bearing capacity of the proposed solution eliminates ductility and increases the strength of the entire joint.

Conclusions. The proposed assembly is lighter than its counterpart on glued rods, and the lack of a regulatory framework for such structures forces designers to make standard decisions. The proposed method for calculating the nodal connection can improve reliability, as well as increase the economic efficiency of the entire structure. The possibility of using the proposed node has been confirmed by numerical modelling methods.

Introduction. The use of mixed binders with an increased content of active mineral additives allows improving a number of the most important physical and mechanical properties of concrete. However, a decrease in the proportion of clinker for structural concrete may negatively affect the durability of the reinforced concrete product and the structure as a whole, due to a potential decrease in the pH of the pore liquid of the concrete. Gypsum cement-pozzolanic binders are materials with a small clinker fund, since gypsum binder, which has an acidic environment, predominates in their composition. Therefore, when introducing load-bearing products and structures into production, it is necessary to check the protective properties of concrete in relation to steel reinforcement.

Materials and methods. To prepare the gypsum-cement-pozzolanic binder, we used gypsum binder of grade G-5, cement binder of grade CEM I 42.5N and pozzolanic mineral additives: natural zeolite, microsilica and fly ash. The pH and ionic concentration values of hydrated suspensions with various active mineral additives, both mono- and binary modifications, were studied using potentiometric and conductometric methods. Compressive strength was estimated after 7, 28 and 90 days of hardening in accordance with GOST 10180–2012; water absorption — according to the method of GOST 23789–2018; water resistance was estimated by the softening coefficient.

Results. As a result of the experiments, a composition of gypsum-cement-pozzolanic binder with high protective and physical-mechanical properties was obtained, which can be used for the production of structural quick-hardening concrete.

Conclusions. The obtained results indicate sufficient protective properties of concrete based on gypsum-cement-pozzolanic binders in relation to steel reinforcement: a pH of at least 12 and a composition containing 60 % gypsum binder, 25 % Portland cement and a binary active mineral additive based on microsilica and natural zeolite in a ratio of 2:1 by weight.

Introduction. In practice, standard technical characteristics (such as cone slump, mixture spread diameter, etc.) are used as indicators of the efficiency of plasticizing additives. However, these characteristics make it difficult to judge the rheological properties of cement systems. This paper is devoted to analyzing the correlation between mobility indicators and rheological characteristics, as well as the regulation of rheological parameters of cement mixtures considering electro-surface phenomena.

Materials and methods. Fine fillers (quartz, marble) with different electro-surface properties (Ssp = 300 and 600 m2/kg) were used. The binder was CEM I 42.5 N produced by CJSC “Oskoltsement”; chemical additives included the superplasticizer Polyplast SP-1 and the superplasticizer Sunbo 2021. Rheological characteristics of the dispersions were determined using a Rheotest RN 4.1 rotational viscometer, and mobility was assessed with a mini-cone. Surface microanalysis was conducted using a TESCAN MIRA 3 LM scanning electron microscope. Specific surface area was measured with a PSKh-10a device, and the electrokinetic potential of particle surfaces was measured using a Zetasizer Nano ZS.

Results. It was shown that the greatest thinning effect was observed in suspensions where the predominant surface charge of mineral filler particles was opposite to the charge of the functional group of anionic plasticizing additives, and vice versa. It was revealed that the type of mineral filler had a stronger impact on mobility indicators than on rheological characteristics. A correlation between plastic viscosity and mobility (spread diameter) was established. Based on the analysis of the obtained rheological data and mobility, flow regions of cement dispersions were identified.

Conclusions. The use of fine powders positively influences the flowability of cement dispersions, with marble filler being more effective than quartz. In the region of moderate dispersion thinning (spread diameter = 60–170 mm), the cone spread is consistent with the rheological properties of cement systems. Practical application of the research results presented in this paper will enhance the efficiency of superplasticizers and superplasticizers and simplify the assessment of the rheological flow regime of dispersions.

Introduction. The present paper shares new results of research devoted to improving the operation of conventional reverse osmosis. A new technological solution is proposed to escape scaling on the membrane surface. Applications of nanofiltration membranes provide a reduction of operation costs connected with chemical purchases to ensure pretreatment and chemical cleaning and also to pay for concentrate discharge into the sewer.

Materials and methods. In the paper, the experimental methods developed earlier were used, such as the evaluation of membrane rejection and control of permeate quality as a function of the initial feed water volume reduction coefficient K; evaluation of calcium carbonate scaling rates and organic fouling rates in membrane modules. The experimentally obtained relationships are presented: dependencies of calcium concentrations and TDS values on the initial volume reduction coefficient K values and product flow reduction with K value relationships. Also, the second series results are presented that demonstrate dependencies of calcium carbonate growth rates on K.

Results. Results of the required numbers of membrane modules are obtained to tailor the 3 cubic metres per hour capacity membrane facility and the results of economic calculations are also obtained.

Conclusions. The use of nanofiltration membranes on each stage of water treatment allows for the escape of deposition of sparingly soluble salts on the membrane surface and excludes antiscalant dosing and routine membrane cleanings. The use of the developed technology featured by the low operational cost due to reduced reagent consumption and concentrate discharge into the sewer.

Introduction. In the context of modern construction, where the requirements for energy efficiency and sustainability are growing every year, the need for an integrated approach to modelling the subjects of engineering systems is becoming especially relevant.

Materials and methods. To develop a mathematical model of the life cycle of building engineering systems, a method for compiling a closed directed graph was used. Mathematical and graphical processing of the obtained results was carried out.

Results. An approach to modelling the processes of degradation and restoration of engineering systems is presented, taking into account the dependence on time and the current state to reduce the costs of routine and scheduled repairs. The relationship of each engineering system as a full-fledged complex is established. Problems affecting the operability of building engineering systems are identified. In order to model the dynamics of system performance change, a coefficient considering instantaneous deterioration and gradual deterioration Сloss is proposed. A practical forecast of the research results for the life cycle of a complex of engineering systems of a capital construction project is presented.

Conclusions. The obtained results can be used to design building engineering systems and assess their functionality throughout the entire life cycle of the building. A mathematical model of flow distribution in the engineering systems of the building was developed. A unique coefficient is proposed that takes into account the probability of occurrence of various types of negative impacts. In the future, the proposed system will allow to abandon the calculation of annual expected losses caused by hazards and instead focus on assessing the combined impact of several hazards in the context of the life cycle of engineering systems.

Introduction. The author analyzes average price changes in primary and secondary segments of the Moscow housing market, spanning from 2010 to 2024, with a breakdown into mediocre, better-quality, and luxury apartments, and presents price projections for quarterly periods of 2025–2027 per square meter of apartment space.

Materials and methods. The study is backed by the official data available from the Federal Service of State Statistics and covering the period of 2010–2024. Winter’s exponential smoothing models were applied to make projections that encompassed linear trends and additive seasonality.

Results. In 2010–2024, the average annual price growth rate was 4.8 % for all types of apartments on the secondary Moscow market, and 6.5 % for all types of apartments on the primary Moscow market. As for “mediocre quality” (standard) apartments, the average annual price growth rate was 5.3 % for the secondary market and 7.1 % for the primary market. As for better-quality apartments, the average annual price growth rate was 4.8 % for the secondary market and 8.1 % for the primary market. As for luxury apartments, average annual price growth rates were 6.5 % for the secondary market and 6.2 % for the primary market. The author’s projections for the secondary housing market suggest a 2.5 % increase in the average price per square meter of all types of Moscow apartments as of the year-end 2025 relative to the year-end 2024. The same value will reach 5.3 % as of the year-end 2026, and 8.2 % as of the year-end 2027. For the primary market, the author suggests a 6.7 % price increase as of the year-end 2025; a 11.3 % price increase as of the year-end 2026, and a 15.9 % price increase as of the year-end 2027 relative to the same value for 2024.

Conclusions. If the same trends persist, the greatest price growth rate is anticipated for luxury housing on the secondary housing market, and the smallest price growth rate is projected for mediocre and better-quality apartments on the secondary
housing market.

Introduction. The relevance of the study is explained by the fact that the issues of calculation, assessment of the bearing base, and structural design of piles have been worked out in sufficient detail, while the issues of evaluating the effectiveness of pile work at the stages of new construction and various types of repairs have not been sufficiently investigated. The aim of the study is to identify the most significant factors affecting the complexity of pile foundations with the development of a model of their impact on the resulting indicator. The objective of the study is to determine and calculate the weight of factors affecting the complexity of pile work and to develop a mathematical model that takes into account the nature of the influence of the most significant factors.

Materials and methods. To achieve the goals and objectives of the study, expert assessment, statistical processing methods, and information evaluation were used, which made it possible to identify the relationship between variables and quantify their accounting.

Results. A mathematical model has been developed to assess the complexity of work in the construction of pile foundations, which makes it possible to identify the nature of the influence of significant factors on the resulting indicator. As the most rational and universal, according to the set of advantages, the study adopted the method of “pile pressing”, with the technology of work supplemented in this study.

Conclusions. The conducted study made it possible to identify and study the most significant factors affecting the efficiency of pile work. The developed mathematical model (regression equations) allowed to comprehensively take into account the degree of influence of each factor on the resulting indicator Yt (labour costs), which will allow to effectively plan the work on the construction of foundations.

Introduction. Construction companies around the world are striving to implement tools for the comprehensive optimization of their business processes, while adopting the principles of “lean production”, the development of which is reflected in “lean construction” technologies. Within the framework of such tools, issues of both organizational and technological nature are considered, aimed at reducing or localizing losses, improving coordination between subjects of the construction process, achieved in a digital environment.

Materials and methods. The paper analyzes scientific papers on the topic of lean construction by Russian and foreign scientists reflected in the bibliographic catalog of scientific publications reflected in OpenAlex and ResearchGate, uses data from a historical case of the construction of the fourth power unit of the Kalinin NPP, and analyzes individual public documents of the authorities of the Russian Federation and the Republic of Belarus. In the course of completing the tasks, the following scientific research methods were used: historical analysis; synthesis; generalization and formalization, which made it possible to form a set of tools and determine approaches to the implementation of lean construction technologies.

Results. Resolving contradictions and optimizing processes in the subject area of the study is built taking into account the available lean construction technologies, which should be integrated into the current activities of the organization, subject to their availability and economic feasibility. “Integrated Project Management” (IPD), “Job Order Contacting” (JOC), hybrid models integrating the above models; and the prospects for their development are defined.

Conclusions. The implementation of lean construction technologies and related tools in Russia has not yet become a mass practice, despite significant scientific and practical interest in this topic among large construction organizations, divisions and infrastructure companies. The obtained research results allow us to formulate a comprehensive approach to managing losses and creating value within the framework of the project approach.

Introduction. The authors of the paper studied the matter of expediency and efficiency of the use of the technologies of information modelling or building informational modelling (BIM-technologies) during the implementation of investment-and-construction projects. The attention of the authors was concentrated on the stage of dismantling of buildings and structures as well as on management of the waste which is formed at the same time.

Materials and methods. The works by domestic and foreign authors and also the maintenance of the official sites of the construction organizations, the data describing experience of dismantling of buildings, which are contained in printing editions, scientific publications, practical research, Internet, materials of academic-and-research conferences, seminars and forums, publications of Rosstat served as the materials of the research. During preparation of the paper the authors used the system and process approaches, such methods of scientific research as observation, the description, quantitative and statistical analysis, the comparative and comparative analysis.

Results. The authors studied the innovation technologies, which can be introduced in the activities for dismantling of buildings and structures. Domestic and foreign experience of the use of information technologies for dismantling was analyzed, benefits of BIM-technologies were revealed.

Conclusions. As the result of the conducted research the authors made the conclusion, that the implementation of the BIM-technologies in organization activity performing dismantling of buildings and structures allows to gain some positive effects: to reduce terms of works, to reduce their cost, to increase security, to reduce impact of negative factors on an ecological situation and on the comfort of accommodation, to improve waste management. Nevertheless, there are several barriers of introduction and effective use of BIM technologies in the dismantling activity. Thus, the most perspective directions of further researches were formulated.

Introduction. For assessing the cost of construction project, cost estimates are developed, and then the project budget is used as one of the cost control tools for contracting organizations. The construction project budget in contracting organizations is used to assess the profitability of project implementation, improve the efficiency of material and financial resource management, and assess the potential of project solutions. It is developed on the basis of cost estimates, but has differences in structure and content, which are given in this paper.

Materials and methods. The paper provides a comparative analysis of the structure and content of the estimate calculation and budget of an investment and construction project in a contracting organization. The application of lean approaches and methods in planning the implementation of a project by contracting organizations is considered, in particular, in assessing and budgeting a project in contracting organizations.

Results. The paper provides the concept of a project budget in a contracting organization, as well as a description of the process of its creation, and considers the functions of the project budget. During the study, fundamental differences between the estimate calculation and the project budget, their structure and functions were identified and described. Using the example of a heating network construction project in Moscow, a comparative analysis of the estimate calculation, project budget and actual data on the implementation of the project was made.

Conclusions. The development of a budget for each project is necessary for internal control of project implementation costs in a contracting organization, and the use of a lean construction approach offers effective tools for reducing costs and achieving the planned profitability for contracting organizations.