Modern designs of water heating systems are saturated with different types of regulators, but their use is more often justified not by a systematic approach, but by solutions necessary for the operation of the system in its individual parts. The objectives of the presented work are to obtain and systematize experimental data to study the variable hydraulic mode of operation of horizontal water heating systems using apartment stations. In this paper, a problem in the field of development of modern water heating systems that needs to be solved is formulated. The analysis of the schematic solution of the heating system, as well as possible design options, was carried out. A simulation of the multivariate hydraulic mode of operation of the heating system of an apartment building was carried out on the simulator stand. The results of an experimental study are presented, and based on changes in design costs and the value of the adjustable pressure drop in parts of the system, proposals are made to reduce the cost of water heating systems for buildings under construction, as well as suggesting an increase in the ease of setup and quality of system regulation.

Keywords: balancing fittings, hydraulic characteristics research, water heating system, automatic regulators

The article presents the results of a study aimed at forming tables for a preliminary assessment of the load-bearing capacity of a running meter of a centrally loaded wall of various thicknesses, heights and strengths made of masonry with elastic characteristics α = 1000, 1200, 1500.The results of calculating 540 different variations of a centrally loaded stone element with different types of stone and mortar material are analyzed. The results of the study make it possible to exclude the use of a software package for preliminary determination of the bearing capacity of a centrally loaded stone structure and can become part of a practical guide for engineers involved in the technical inspection and design of masonry structures.

Keywords: bearing capacity, wall, stone structure, elastic characteristic of masonry, centrally loaded element, stone, brick, block, masonry mortar, coefficient of longitudinal bending, flexibility

The development of methods for calculating structures made of ultra high-performance steel fiber-reinforced concrete (UHPC) in terms of strength and deformations is an important step towards the introduction of this innovative material into the practice of design and construction. This paper presents the results of finite element modeling of the operation of UHPC I-beam in the area of action of shear forces. The SMM model integrated in the OpenSees framework application is used for the walls of beams under conditions of flat stress. The authors have added new classes of materials that implement the averaged deformation laws of UHPC (with and without fiber) and the reinforcement placed in it. The calculations showed good convergence with the authors' own test results of the UHPC I-beams, as well as with the results of experiments by other researchers.

Keywords: shear strength, shear force, ultra high-performance steel fiber-reinforced concrete, I-shaped beams, OpenSees

The choice of the method of force calculation of building structures is preceded by an analysis of the static determinacy and immutability of the rod system using structural formulas, while for different types of structures - for beams, trusses, frames, arches, etc. - sources offer different formulas. It is shown that for the structural analysis of all rod systems it is sufficient to determine the degree of structure anomaly using the formula of P.L. Chebyshev. The development of the linear-monad theory of structure makes it possible to formalize the dependence of the number of rods and hinges on the number of external and internal contours in the synthesis of both normal and anomalous structures

Keywords: beam, truss, frame, arch, structure, analysis, synthesis, immutability, definability, degree of anomaly, rods, system, contour, monad, hinge

Review of fresh patents on nuclear power station cooling systems and current problems & future of nuclear power stations.

Keywords: nuclear power station, cooling systems, patents

The situation of occurrence, identification and management of risks arising during the construction process is analyzed. Uncertainty of decision-making in construction projects involves the creation of methods that ensure the reliability of decisions and their effectiveness. Such a method was developed in the Russian Project Management Association. The paper provides an example of using this method on a real construction site. An analysis of risks arising during the implementation of a construction project was conducted, a risk map was created for this project and the PERT method was applied when creating a calendar plan.

Keywords: uncertainty, risk event, probability, risk, damage, danger, reliability, risk analysis, investment and construction project, PERT method

Based on the results of experimental studies of the propagation of bending waves, the ability of the developed technique to assess the strength of a brick treasure is considered. A comparative analysis of the strength of the masonry was carried out using different methods (L.I. Onishchik formula, Eurocode 6). According to the correlation dependencies between the velocity of propa-gation of elastic waves and the strength of masonry, the presented practical data made it possible to prospectively evaluate the method using bending waves in the survey of buildings and struc-tures.

Keywords: experimental studies, brickwork, elastic waves, bending wave velocity, strength

The method of determining the stress-strain state of metal poles of power transmission lines during the technical examination of electric grid facilities is analyzed. An example of a calculation using the automatic LIRA software package is given. The most stressed sections of structures are determined. The calculated method confirms the hypothesis that the triangular cross-section of the traverse of the portal intermediate support of the 500 kV overhead line is more economical (more efficient) than a tetrahedral (classical) cross section.

Keywords: building structures, metal structures, energy facilities, stress-strain state, technical expertise

Providing the population with comfortable housing has always been a pressing issue. However, there are very few formalized criteria for this, apart from the regulation of minimum floor areas. In this context, the article deals with the problem of evaluating the efficiency of residential space design solutions in terms of their logistical comfort. For this purpose, a method is proposed that uses the apparatus of graph theory and allows to calculate the time cost of an "idle" move for a representative of a given social group in relation to the evaluated design solution. An idle move is a user's movement between characteristic functional zones of the layout. A special matrix is used to model the links between these zones, the construction of which is similar to that of the incident matrix in undirected graphs. As an example of the applicability of the proposed approach, several variants of layouts of one-room, two-room and three-room flats are considered. The comparison of the obtained results for different types of layouts, including those that existed 15-20 years ago and modern ones, indicates a tendency to increase the logistic comfort of modern layouts.

Keywords: planning solution, logistic comfort, idling, graph theory

Advanced nuclear power technologies such as small modular reactors (SMRs) and micro-reactors, a subset of SMRs, have the potential to play a key role in the coming nuclear power expansion. Connect with technical innovators, manufacturers, designers, and government regulators to discuss advancements and gain insights on the latest AMR and SMR projects in the UK and globally. 2024 year's world patents are presented.

Keywords: nuclear technology, small modular reactor, micro-reactor, modern patents

Authors considered the thermal inertial properties of some building envelope constructions which included the changes of internal surface layer materials. Researchers described the thermal and physical characteristics of 6 building surface layer materials. It has been determinate the radiant temperature of building envelope inside surface with changes of wall construction after 225 hours cooling process and initial temperature equal to +23 оС. Authors defined the cooling time of building envelope inside surface to 0 оС at different types of surface layer materials. Numerical experiment was done with modern program complex “Stf”. Modeling process was completed in program which was realized with finite difference method and constant heat transfer coefficient. There are new experimental results which were determinate during the research and realizing the mathematical model of non-stationary element’s cooling process. Results could be interested for researchers of thermal phenomena in building envelopes and designers of microclimate engineering systems in buildings and structures.

Keywords: air temperature, radiation temperature, stationary regime, non- stationary regime, building envelope, emergency regime, thermal inertia, inside surface layer, program, building materials

The article shows the importance of analyzing the state of strength properties of old wood during restoration work and monitoring the state of the structure. In particular, the physical and mechanical properties of wood during long-term use in an aquatic environment are analyzed. Changes in the chemical composition of wood as a result of use in the water of the Gulf of Finland are determined. Using the example of logs of the crib foundation of the Kronshlot fort, it is described how a change in the chemical composition of the material affects its strength properties.

Keywords: Mechanical properties of wood, long-term strength, chemical composition of wood, water-soluble extractive substances

Slag-alkali binder (SAB) is obtained by polymerization of granulated blast-furnace slag (aluminosilicate component) ground in a ball mill with an alkali activator, resulting in an environmentally friendly hydraulic polymer binder. Slag-alkali concrete (SAB) based on SAB has become an alternative to traditional concrete based on portland cement (PTC). Reinforcement bars in combination with SAB make it possible to obtain concrete structures with high adhesion properties to reinforcement compared to concrete based on portland cement. However, due to differences in the production process of SAB, there are obvious differences in technical properties, including adhesion characteristics. However, proper standardization is needed for its production and operational testing to limit contradictory results in the laboratory and on the construction site.

Keywords: metallurgical waste, granulated slag, crushing, chemical activation, reinforcement, adhesion, strength

The rocks that form a natural geological reservoir for underground gas storage, during the operation of UGS, are exposed to prolonged cyclic loads caused by periodic injections and withdrawals of natural gas. At the same time, it is possible to develop and accumulate residual deformations in rocks that cause irreversible changes in the properties of rocks and this must be taken into account when designing and operating UGS.

Keywords: underground gas storage, geomechanical modeling, cavern, salt massif, deformations

the work is devoted to a comparative analysis of various calculation and mathematical models among themselves. The calculation of the frame joint of reinforced concrete structures is performed: a pylon and a cantilever beam. Three methods for performing the calculation of this joint are proposed: an analytical method, a rod FEM model and a volumetric FEM model. The analysis of the calculation results is performed: a comparison of internal forces and calculated reinforcement. The consequences of a superficial analysis of the structure and simplification of calculation models are shown using the example of damage to a real structure under the action of operational loads.

Keywords: reinforced concrete console, structure calculation, node calculation, Lira 10, Russian software, optimal design of reinforced concrete structures, reinforcement analysis

Geopolymers and alkali-activated materials are cement-free composites formulated by activating alumino-silicate materials, such as fly ash, meta-kaolin, and silica fume, and calcium-rich materials. The Geopolymer Materials Market grew from USD 12.48 billion in 2023 to USD 15.69 billion in 2024. It is expected to continue growing at a CAGR of 29.46%, reaching USD 76.07 billion by 2030. Today we found about 750 patents of USA, China, Japan and other countries. The selected last year patents have emerged on the usage of geopolymeric mortars for 3D printing, grouting, sewage lining, and wastewater treatment.

Keywords: geopolymers, alkali-activated materials, market of geopolymers, patents on geopolymers, application in in civil engineering

The stability calculation of a П-shaped hinged frame is considered. The concept of r-like frames is introduced as frames with the same ratio r of the linear stiffnesses of the transom and the strut. It is shown that the parameter vcr , which determines the critical load on the frame, is the same for r-like frames. Approximate formulas allowing to determine the critical load parameter vcr and design lengths of compressed bars with an error not exceeding 2% are obtained.

Keywords: flat frame, stability, critical force, reduced length coefficient, r-like frames, approximation, least squares method

The article is based on modelling several variants of information diagrams of a corrugated monolithic ceiling of an industrial building. The information model has been transformed into an analytical model. The comparative analysis of all calculation models was carried out visually and in numerical aspect. The efficiency of BIM-technologies in design with the application of software complexes «Renga», «CAPFIRR-3D» and «LIRA-CAD» is also considered in the calculation and construction section. The comparative analysis of three variants of the joints of the beams and the slab of the covering was carried out. The analysis of the stress-distorted state of the calculation circuit was also performed.

Keywords: ribbed slab, industrial building, design of buildings and structures, BIM-technologies, calculation scheme, information model, rigid insert, stress-strain state, finite element method

The article discusses issues of improving the quality and safety of pedestrian and vehicle traffic in underground linear structures. The main parameters of traffic safety in tunnel-type transport structures are considered. The scope of application of luminescent and retroreflective materials in the construction and operation of concrete and asphalt concrete pavements has been determined. Recommendations are given for the use of special luminous materials in construction practice.

Keywords: concrete, asphalt concrete, reflective coatings, luminescent materials, traffic safety

In this article the existing principles of application of the illusion technique in architecture are considered. The classification of objects by purpose is presented, the key features of classification groups are highlighted. Examples of already existing constructed buildings with different typology are given and analyzed. The target direction of the article is based on the creation of the concept of volume (building) with the use of optical illusions to form a complex solution to clarify the overall concept of the object and achieve the effect of paradox in the viewer. The article also describes in detail the art-architectural and constructive solutions of the proposed concept with the definition of the exact location of the building in relation to the view and approach to it.

Keywords: Illusion, architectural volume, complex solution, paradox, dematerialization, visual perception, structural element, mirrored surface, hovering effect, tilt angle, master plan organization

The article describes the main problems associated with the principles of calculation and design of building structures of buildings and structures in seismically active areas in accordance with the provisions of the regulatory document SP 14.13330.2018. The difficulties that may arise when using foreign regulatory requirements in terms of design and calculation are noted. The calculation of a flat steel multi-story frame for the main and special combination of loads and impacts is considered. The frame calculation for a special combination is performed according to SP 14.13330.2018 with and without taking into account the additional requirements of foreign design standards ASCE / SEI 7-22, ANSI / AISC 341-22. The requirements of foreign standards were not taken into account in full, but only in terms of increasing the reliability of the structure, for certain positions. The change in the parameter of the frame metal consumption for various calculation options is analyzed. Conclusions are formulated and recommendations are given on how to reduce the metal consumption when calculating for seismic impact, taking into account the increase in the reliability of building structures.

Keywords: finite-element schemes, columns, crossbars, seismic action, steel frames, flat frames, design, limit states, material consumption, optimization, reliability, special combinations, combination factors

The article provides an analysis of the state of the rationing issue in terms of performing the calculation justification and design of reinforcement of reinforced concrete structures using external reinforcement systems based on carbon fibers. The normative documents of the Russian Federation and foreign ones are considered, the analysis of the use of external reinforcement based on composite materials for structures of various types of work is carried out, the disadvantages of existing calculation and design methods are highlighted. In conclusion, recommendations are given on the appropriate improvement of calculation and design methods.

Keywords: external reinforcement, carbon fiber, reinforcement, restoration

The article presents the results of the laboratory test and finite element modeling of the facade basket design for the outdoor unit of the split system. A comparative analysis of the obtained data is performed. During the modeling, the main possible design situations were taken into account and the perilous zones were determined, in which destruction is expected. To confirm the obtained design values, a full-scale test was carried out, in which wind pressure was modeled using two horizontally applied loads. Based on the test results, it was determined that the modeling method used corresponds to reality, and the nature of destruction and maximum permissible loads were also established. Based on this, a conclusion was made about the suitability of using the facade basket design option considered in the article for the specified operating conditions.

Keywords: finite element model, testing, load-bearing capacity, reliability, deformability, air conditioner basket, bracket, destruction

The article examines the two-dimensional flow around rectangular cylinders with an aspect ratio from 0.1 to 2.0 using the k-Realizable turbulence model with a Reynolds number of 2×E5. Numerical calculations in the ANSYS Fluent program have obtained changes in the coefficients of drag, transverse force and the Struhal number depending on the size of the prism section. The calculations were carried out at the intensity of turbulence of the incoming flow 2% and 4%. According to the results of calculations, it was found that with turbulence 4%, there is a good coincidence of the total aerodynamic characteristics with the available experimental data.

Keywords: flow around a rectangular cylinder, k-e Realizable turbulence model, aerodynamic characteristics of a rectangular cylinder

The architecture of multifunctional residential complexes (MFRC) is considered in the aspect of “resistance” to external factors and influences. There are four levels of formation of the MFRK: the level of urban planning structure; level of volumetric-spatial organization; level of functional and architectural planning structure; the level of compositional organization and search for the expressive appearance of the MFRK. At each of the identified levels, the “target” indicators of “sustainable architecture” are achieved. The process of forming the MFRC is considered as a sequence of combinatorial search stages and procedures based on modeling the geometric parameters of the visual model of the MFRC in order to get as close as possible to the “stability indicator”. Four methods of combinatorial search modeling are proposed: the method of “overlaying” planning frames; method of “tracing” the formative contour; method of “collaging” functional planning elements; a method of combining “regular grids” in the public, business and residential parts of the MFRK. To intensify combinatorial search procedures, it is proposed to use digital design technologies.

Keywords: university complex, transit urban spaces, scenario approach, functional-thematic zones, architectural and environmental modules