Introduction. In manufacturing tubular concrete columns, attention should be paid to a technology of filling a steel tube with a concrete mixture. In practice when a concrete mixture is being fed into a tube from the top, a proper quality of concreting a structure is not guaranteed. In this study, the aim was to test the effectiveness of a technology of forming columns with a self-sealing concrete mixture by means of pressure concreting.

Materials and Methods. Experiments to study the effectiveness of the suggested technology for forming a tubular concrete column with a saturated content of longitudinal and spiral reinforcement were conducted on a transparent model. A self-compacting mix composition was selected that ensured the required workability, flowability, homogeneity, and absence of stratification. Through the course of the experiments, the process parameters were adjusted with the speed of filling the structure with the concrete mixture as the most important one. The uniformity of concrete distribution throughout the model was monitored.

Research Results. The experiment indicated that the concrete mixture easily reached all of the areas of the structure with no loss of quality. No air bubbles were observed on the surface of the structure, indicating high-quality compaction of the mixture. Concrete strength and density variations in the upper, middle, and lower zones of the structure were minimum. The resulting concrete is characterized by a homogeneous structure, with a uniform, evenly distributed composition with no significant voids or inhomogeneities throughout the entire volume.

Discussion and Conclusion. The absence of formwork, scaffolding, and other equipment, high speed of concreting significantly reduce the time and labor intensity of column installation. All of these, combined with the achieved concrete quality, open up avenues for a broad-scale use of the pressure concreting method in construction projects in the Russian Federation. Further work is needed in order to develop a method for ultrasonic quality control of concrete in tubular concrete columns.

Introduction. At the current stage of science and technology development, the issues of vibration protection of buildings are being intensively investigated, particularly for special structures of a high responsibility class. Various damper designs are also being developed and tested. Modeling the response of damper systems is an urgent task with both deterministic and stochastic approaches to solving it. This study demonstrates the features of the stochastic approach in a variant of the mathematical model of the generalized Ornstein-Uhlenbeck process. It is possible to the effect of using a nonlinear damper in a specific case can be evaluated by means of this model, and the conclusions can be made regarding its benefits.

Materials and Methods. The major research method is the solution of a stochastic differential equation. A numerical experiment is shown with a real example of analyzing the dynamic response of a turbo unit with a viscoelastic nonlinear damper to a random seismic impact. The application of the generalized Ornstein-Uhlenbeck process for mathematical modeling of the dynamic response of damping devices to seismic impacts on critical energy infrastructure is analyzed.

Research Results. A stochastic model is set forth that takes into account both the random nature of seismic excitations and the nonlinear rheological characteristics of dampers. The results of the numerical experiment confirm that while calculating by means of the described model, the use of a nonlinear damper is justified, the mean-square values of the displacement response are reduced by more than two times helping to reduce seismic risks for the turbine unit as well as to increase its dynamic stability and reliability of operation under the action of random impacts.

Discussion and Conclusions. The developed methodology provides a quantitative assessment of the effectiveness of a variety of classes of damper systems and allows for parametric optimization of their settings in order to maximize their protective capacity and to reduce the vibration and dynamic loads on energy equipment. The theoretical significance of the study is the suggested calculation methodology, while the practical significance is in the assessment and recommendations for making use of viscoelastic dampers for a high responsibility class of structures.

Introduction. Modern architecture is characterized by the extensive use of buildings with complex curvilinear forms that are high expressive yet require tackling new engineering challenges associated with ensuring their aerodynamic stability. Normative methods for calculating wind loads are largely focused on buildings with a simple geometric shape and fail to account for the flow characteristics of free-form shells. This highlights the need to systematize modern approaches to analyzing wind effects on such structures. The aim of the study is to summarize and compare normative, experimental, and numerical methods for assessing the aerodynamic stability of complex-shaped buildings.

Materials and Methods. The object of the study is a building with a biomorphic three-beam structure characterized by smooth contours and a complex spatial topology. In order to analyze its aerodynamic characteristics, numerical simulation of wind flow was performed using the RWIND Simulation software. The study was conducted in order to identify the flow characteristics and distribution of aerodynamic loads on the surface of a complex-shaped building.

Research Results. As a result of the calculations, distributions of the pressure, velocity, and pressure coefficients over a building surface were obtained. Zones of a local pressure increase and dilution were identified in the areas of volume junctions and roof recesses. It was found that the curvilinear form of a building contributes to a reduction in the overall aerodynamic drag; however, it also induces the formation of local vortex structures, which is to be considered in designing façade and roofing systems.

Discussion and Conclusion. The results confirm the effectiveness of applying Computational Fluid Dynamics (CFD) methods for analyzing the aerodynamic properties of complex-shaped buildings. The integrated use of normative, experimental, and numerical approaches ensures a more accurate assessment of wind effects and contributes to developing a cutting-edge methodology for designing aerodynamically stable architectural structures.

Introduction. The development of the construction industry in Russia involves both emerging technologies and materials and traditional construction methods. One of the well-known tools in this country is wooden housing construction. Apartment buildings are being built from wooden CLT panels, glued timber, beams made of unidirectional veneer, etc. are commonly employed. Modern architecture seeks to create large open spaces for free planning. In wooden buildings, it is not always possible to organize such spaces due to a limited length of lumber being produced. Studies aimed at designing extended panels from wood are thus gaining momentum. The aim of this study is to develop new designs of wooden panels for cladding and flooring of buildings from standard lumber, plywood and oriented strand boards with spans exceeding the standard length of boards, to identify the limits in the load-bearing capacity of such panels, as well as to conduct their geometric calculation.

Materials and Methods. Two types of box-shaped panels made of wooden planks, plywood and/or oriented strand boards are considered. The load-bearing capacity of the suggested structures is estimated by means of both traditional methods of material strength and computer models.

Research Results. The design of extended panels is described differing from the known overseas analogues and is free from the inherent disadvantages of the latter. Geometric calculation of the suggested structures is performed. The rational size ratios of the sizes of boards that make up the panels are identified. Design limitations for individual elements of products are established. Computer models of the panels are designed and employed in order to identify the applicability limits of the suggested structures.

Discussion and Conclusion. As a result of the research, new designs of wooden panels for flooring and cladding of buildings with possible spans exceeding the standard length of lumber and made with no use of costly materials have been developed. The simplicity of the design makes it possible to organize manufacturing of products in small-size industries with complex and costly equipment involved. The panels can be employed for long open spaces in wooden buildings and structures for a broad range of purposes.

Introduction. The calculation of cylindrical stone arches of historical buildings is often performed in a core setting. At the same time, the ratio of bending moments M and longitudinal forces N, as well as cracks has a major effect on the loadbearing capacity of arches. The latter does not allow the analysis of the load-bearing capacity of arches by means of the standard methods. The aim of the study is to develop a methodology for assessing the load-bearing capacity of cylindrical stone arches with cracks.

Materials and Methods. The experimental studies confirm that one or even a few cracks are not invariably a sign of exhaustion of the load-bearing capacity of arches. The upper limit of the load-bearing capacity is due to such a number of conditional hinges (cracks), which converts the arch into a kinematic mechanism. It is possible to analyze the operation of vaults with cracks up to their physical destruction by means of the so–called interaction dependencies reflecting the limiting ratios M_Rd–N_Rd.

Research Results. The interactive dependencies of M_Rd–N_Rd were identified experimentally. The experiments also revealed the mechanisms of destruction of the cylindrical vault depending on the ratio M_Rd–N_Rd. Thus, under the action of only the bending moment, the destruction of the sample occurred along an unconnected section of the masonry; under the action of only the compressive force, as a result of the formation of longitudinal cracks; under the combined action of the compressive force and the bending moment, nature of the destruction depended on the ratio of these forces. The numerical model have been verified that can be used in order to design interactive dependencies.

Discussion and Conclusion. A methodology has been developed for assessing the load-bearing capacity of cylindrical stone arches with cracks using interactive dependencies reflecting the limiting ratios M_Rd–N_Rd. It is shown that it is possible to directly design interactive dependencies with numerical solid-state models, having previously "fine-tuned" them to the results of a number of simple masonry tests. The actual values of M and N in the cross sections are identified using the rod models of the arches. The load-bearing capacity of the arches is evaluated by comparing a certain combination of M-N with the interaction dependence curve.

Introduction. In order to ensure earthquake resistance and to reduce seismic loads, a spatial calculation of the load-bearing structures of a multi-storey building of complex shape was performed. This article analyzes the design system, computational and dynamic model taking the main and special combinations of loads into account.

Materials and Methods. The calculations were performed by means of the analytical method and the finite element method (FEM) in the STARK ES software package.

Research Results. The results of dynamic calculation are obtained for basic and special combinations of loads and corresponding combinations of internal forces in the calculated structures of a multi-storey building of complex shape. A total of 53 loadings were used.

Discussion and Conclusion. The results of the calculation of a multi-storey building of complex shape have shown that the required strength, rigidity and stability of load-bearing structures are ensured in the design situation in question.

Introduction. Bamboo structures have become widespread in Asia, Africa, and Latin America. Bamboo is a gradient material with unequal cross-sectional properties and characteristic anisotropy: good properties in the longitudinal and weak transverse directions. The connection of bamboo rods thereby represents a weak point in the design, which is a scientific issue. In modern literature, the lack of the efficiency of various types of bamboo rod joints has been shown leading to a progressive collapse of a structure. The identified gaps in the existing research has enabled us to formulate the aim of the article, which is to develop new types of bamboo rod connections to ensure safe and reliable operation of the truss structure.

Materials and Methods. The object of the study is a bamboo truss with a wall thickness of at least 10 mm. The trusses were calculated by means of the advanced methods of cutting nodes, selecting cross-sections, and designing influence lines.

Research Results. A new design for connecting bamboo rods in the spatial case has been set forth. The advanced spatial hinge is a one-piece hot-forged steel sphere with 18 threaded holes and a machined support surface at angles of 45°, 60° and 90° in relation to each other. A conical steel section is attached at each end of the spatial structure element to transfer force from the bamboo joints to the nodal ones. Due to this tapering cone-shaped section, the nodal joints can be connected to lots of elements at once. The pedestrian bridge truss has been calculated for various load application options. It is shown that the suggested type of connection ensures efficient operation of the spatial structure. The actual reliability factor of 2.33 is 29% over the traditional value.

Discussion and Conclusions. The suggested options for ensuring a reliable connection of bamboo rods are of primary importance in the design and construction of bamboo truss structures of a spatial type. A spherical hinge and a conical attachment with a metal cable create a reliable connection, which is critical for bridge-type structures or residential buildings. The prospects of the work are focused on investigating the efficiency of the suggested compounds in dynamic tasks under a moving load and creep.

Introduction. The construction industry depends largely in compliance with the laws of the market with no in-depth analysis of its development trends as a system. Government regulation of the industry fails to make a full use of an evidence-based predictive analysis, but rather is more frequently guided by international experience in the form of small data. The aim of the study is to bridge this gap by means of a general overview of the research related to the general patterns of the development of construction technologies.

Materials and Methods. The research included the search for information from open sources, its analysis and synthesis in order to identify the general trends in the development of construction technologies. Materials from the authors’ research were employed. The analysis was conducted using the laws of the development of technical systems.

Research Results. The stages of the evolution of building technologies including prefabricated, monolithic, and precastmonolithic methods are discussed. Ways of improving building materials by means of increasing their physical and mechanical properties, reducing weight, and lowering harmful emissions and costs are also identified. It is noteworthy that the improvement of these materials by their direct relationship with structures results in their dynamic development. It is found that the improvement of materials due to the direct relationship in the system with structures also leads to their dynamic development, they become more durable, lightweight, multifunctional and influence architectural and planning solutions increasing useful selling space. Issues hindering the development of digital technologies for the manufacture of structures are noted: control of early hydration of 3D-printed concrete and a relationship with rheology, ensuring interlayer adhesion, strength, introduction of automated reinforcement and generally the relationship between technology, material and performance characteristics in terms of both structural strength and durability. The basic requirements for the design of buildings and structures and their parts are designed: saving space, materials and energy through integrated design, which includes the integration of all the building systems (structural, mechanical, hydraulic, air and electrical) into a single system. The development of the technology of large-block (modular) construction is considered including the research of SUSU employees on the technology of sinking concrete. Attention is paid to the global experience of modular construction and the direction of development of modular integrated systems.

Discussion and Conclusion. It is concluded that the general trends in the development of construction technologies include: acceleration of large-block (modular) and monolithic construction by improving materials (high-functional concretes, enlarged reinforced frames, fibers), use of automated efficient mechanisms, prefab elements, equipping modules with engineering networks; reducing the complexity and increasing the manageability of construction production by reducing labor costs in the proposed construction technologies, automation and digitalization of the major processes; use of information modeling technologies, neural networks, and rational layout of the interior of a building in complex design; improving the functionality and aesthetics of facade technologies.

Introduction. Risk assessment of early cracking during hardening of massive monolithic reinforced concrete foundation slabs due to temperature gradients enhances the relevance of studies of a host of factors related to a concreting technology given the technical capabilities of workers and suppliers of concrete mixtures, as well as weather conditions. While developing technological regulations for concreting with a calculation of the thermal stress state in the early period in order to reduce and control heat dissipation, studies in the field of assignment and regulation of time parameters of the process of forming the body of the foundation slab taking into account the prescription features of concrete mixtures and weather conditions are relevant. The aim of the study is to obtain new data for calculating the time parameters of concreting massive structures using concrete pumps with technical characteristics that are not available in the regulatory framework.

Materials and Methods. The paper presents the results of timing the process parameters of continuous concreting of a massive foundation slab with a volume of 1642 m³ in 13.6 h. The numerical values of the concrete mixture pumping speed, maneuvering time of concrete mixer trucks as well as the coefficients of transition from technical to operational performance of concrete pump trucks with a technical capacity of 170 and 180 m³/h are obtained. The use of concrete pumps with such a capacity at an actual unloading speed of concrete mixer trucks of up to 2.3 m³/min ensures an actual pumping performance coefficient of up to 0.81, which basically corresponds to normal operation.

Research Results. The values of the concrete pump utilization coefficient over a time period ranging from 0.478 to 0.841 with an average value of ≈ 0.66 were obtained. The actual average productivity of one concrete pump during the concreting period was ≈ 61 m³/h.

Discussion and Conclusion. With a distance from the concrete pump truck to the concrete mixer truck waiting area within 25–50 m, the maneuvering time does not depend greatly on the distance, according to 69 measurements, it is no more than 5.76 min with a reliability of 0.95 and is identified by the convenience of an area for maneuvering concrete mixer and access roads. The results can be used in developing process regulations for continuous concreting of similar massive structures.

Introduction. The Russian Federation has adopted a long-term program for the large-scale construction of highways, which will require the construction of a large number of bridges of small, medium and large spans. International experience shows that it is advisable to build road bridges from prestressed reinforced concrete. Moreover, the most effective ones are the span bridge sections of a box-shaped cross-section that are different from girder structures by better aerodynamics, lower labor costs during construction and more attractive external aesthetics. In the literature on numerical analysis of the stress-strain of monolithic reinforced concrete structures, very little information is provided on calculating span bridge structures taking into account concrete creep. The aim of the study was to develop a technique for finite element modeling of long-term deformation of a box section span using an authorized software package. The data from the computational experiments were verified using the ANSYS Mechanical software package.

Materials and Methods. The finite element method in the form of a displacement method in combination with the theory of linear viscoelasticity is employed as a mathematical tool for modeling prolonged deformation of the investigated reinforced concrete structure. In order to formalize concrete creep, S.V. Aleksandrovsky's elastic creeping body model was used. The computational process of numerical integration of the resulting operator-matrix equation is based on the principle of superimposition of effects and the use of the trapezoid formula. The computational experiments were performed on the Microsoft Visual Studio platform and the Intel Parallel Studio XE compiler with the built-in Intel Visual Fortran Composer XE text editor. In order to visualize the simulation results in the form of pictures of the distribution of displacement and stress fields, the descriptive graphics of the Matlab system are employed.

Research Results. A program has been developed and verified for the finite element calculation of reinforced concrete beam structures in a three-dimensional formulation using a discrete reinforcement scheme, according to which the reinforcing frame is modeled by means of two-node beams, and the concrete array is modeled by means of volumetric multilinear finite elements. It is found that for the considered typical box-shaped bridge sections, the adopted pre-voltage scheme is ineffective as it fails to provide the required bending.

Discussion and Conclusion. The results of the calculations of the box section in a linearly elastic formulation obtained using the developed software package and the ANSYS Mechanical software package are compared. A satisfactory coincidence of displacement and stress values at the investigated points has been identified. The stress-strain state of the box section at the stage of prestressing and subsequent loading is investigated. The conclusion is made on the expediency of scientific support at the design stage of such bridge sections in order to increase their load-bearing capacity.

Introduction. In modern conditions of the construction industry development, the concept of the life cycle of construction facilities encompasses not only the design and operation stages, but also the disposal of structural elements, particularly the components of wind turbines (hereinafter referred to as WT) with a service life of 20–25 years. Conventional methods of disposal of used elements of wind turbines display a low environmental efficiency. In the context of the circular economy, innovative solutions for integrating used WT components into construction practice are to be developed.

The aim of the study was to scientifically substantiate a possibility of using recycled wind turbine blades in the construction of children's playground complexes.

Materials and Methods. The study is based on a methodology for analyzing the life cycle of wind turbine blades, taking the specific features of their processing in the construction industry into consideration. The following methods were employed: a systematic analysis of the characteristics of wind turbine blades, a statistical assessment of their life cycle, a comparative analysis of recycling technologies and an assessment of the safety of structures made from recycled materials.

Research Results. As a result of the analysis and research conducted, a technology for processing blades into structural elements of a children's playground complex has been developed.

Discussion and Conclusion. The results confirm the fundamental possibility and practical expediency of employing recycled wind turbine blades as construction facilities in order to design safe and durable children's playground complexes. The developed technological solutions that take into consideration the full life cycle of materials – from operation as part of wind turbines to secondary use in building structures – enable transformation of the environmental problem of recycling into a resource for urban infrastructure development.