Economic development directly depends on the creation of a network of roads of the highest category. Major road construction requires large capital investments and less funds are allocated for the operation of existing roads and infrastructure. Instead of replacing bridge structures, it is necessary to use their reconstruction. The article discusses the problem of reconstruction of bridge structures, namely the restoration of carrying capacity, which has decreased during many years of operation. The relevance of the study, its goals and objectives are noted. A classification of reinforcement structures according to various criteria is proposed. The types of bridge reinforcements often used in practice, their advantages and disadvantages, are analyzed. The presented material is illustrated with photographs of objects. Successful reconstruction directly depends on the qualifications of designers and contractors, since with insufficient reinforcement, the span continues to work and is overloaded and gradually collapses. A modern method of reinforcement based on the use of carbon composite is presented. Significant disadvantages of this method for strengthening bridges and its modification using a tensioning device to secure and tension the carbon lamellas have been noted. The use of a tensioning device allows the superstructure to be partially unloaded from permanent and temporary loads. The main conclusions are presented.

Keywords: bridge, strengthening, reconstruction, truss, carbon composite, lamella, load-carrying capacity, load-bearing capacity, tension

The object of research is C-shaped elements made of thin-walled cold-formed profiles. The subject of the study is the stability of C-shaped rod elements from thin-walled cold-formed profiles. Research goal: development of the calculation process by the finite element method and determination of coefficients of loss of the overall stability of thin-walled cold-formed rods. Method. A numerical-analytical research method is used to reduce the time and volume of settlement operations. The buckling coefficients are determined by finite element analysis of the buckling of the overall stability of cold-formed elements of light steel thin-walled structures using the software package. Result. This analysis results in a table of total weight coefficients for cold-formed thin-walled rods, which can be presented as a table for calculations on medical indicators—a comparative analysis of the inverse numerical-analytical calculation method with the finite element method using the computer program.

Keywords: stability, finite element method, thin-walled cold-formed profiles, steel, coefficients, software package, construction

The paper describes a model of behavior of the connection of wooden structures with glued rods when exposed to negative temperatures. The results of determining the resistance of wood to punching of a glued rod of reinforced joints of wooden structures at temperatures of -30°C, -70°C and +22°C are given. The characteristic features of the destruction of the reinforcing bar and the connection as a whole are revealed.

Keywords: wood, glued rods, extreme temperature and humidity conditions, indentation strength of adhesive bonding of metal rods

This article discusses the process of collecting initial data for the cadastral assessment of cultural heritage objects. It has been revealed that cultural heritage objects have a number of features among other real estate objects, so special attention should be paid to the methodology for assessing such objects. The purpose of the study is to analyze and identify problematic issues in collecting initial data on cultural heritage objects during the state cadastral assessment. The results of the study showed a number of problematic issues related to the type of cultural heritage object, its binding to the cadastral number and the possibility of interpreting the information received to bring it to automatic data processing.

Keywords: state cadastral valuation, cultural heritage object, collection of initial data, interdepartmental interaction, status of cultural heritage object

The paper considers the opportunities and obstacles to the integration of renewable energy sources (RES) in megacities on the example of Moscow. The paper analyzes the applied RES-based generation technologies, taking into account their applicability in large cities. Special attention was paid to the conversion of unused historical dams into small hydroelectric power plants (SHPP) as an integration of RES in megacities. Based on the results of the technical and economic analysis, it was found that the conversion of an unused dam on the Yauza River into a SHPP is justified.

Keywords: small hydropower, unused dam, megacity, renewable energy integration

One of the actual problems in the field of analysing loads and impacts on bearing structures is their identification. It means the point of application, the type of action and its intensity in cases where there is an impact result, but the parameters that caused this result are not determined. For example, it is an accident action, as a result of which the structure is deformed and collapsed. The solution of such problems arises when analysing accidents on load-bearing structures in construction, as well as when monitoring the deformed state of structures in time. The paper proposes to use the principles of neural network modelling to solve the problem of identifying the impact in the form of a concentrated force on the example of beam systems. The values of linear and angular nodal displacements at some action are considered as input data to neurons. As an example, the linearly deformable beam of constant stiffness is considered, the material of which is a continuous isotropic medium.

Keywords: neural network, deflections, load-bearing structure, displacement, deformation, identification

he article considers a plane problem of calculating the interaction of a culvert of different outlines with a soil embarckment, taking into account the constructive nonlinearity. Due to the impossibility of the soil to work in tension, the interaction of the pipe and soil is assumed to be uniulateral. In the problem, the outline of the pipe is changed, other parameters being equal. As the results of the calculation, the area of contact / separation and adhesion / slippage of the pipe with the soil is considered. Based on the results of calculations, recommendations are given for choosing the outline of culverts.

Keywords: constructive nonlinearity, frictional contact, unilateral constraints, linear complementarity problem, numerical models, finite element method

On the example of the beams, the dynamics of systems with unilateral constraints are considered. The algorithm for calculating such systems as a combination of the step method of Newmark and the Lemke algorithm that determines the work scheme of the beam in each time step is proposed. Model tasks are considered with a harmonic exciting force, suddenly applied force, impulse exposure. The numerical convergence of the solution was investigated during the thickening of the temporary grid. It is shown that the accuracy of the solution significantly depends on the determination of the moment of changing the working schemes, since the error of the solution increases with an increase in the events “inclusion/off” of unilateral constraints.

Keywords: constructive nonlinearity, unilateral constraints, linear complementary problem, Lemke's algorithm, structural dynamics, Newmark's method

The article disrible a lot of novel patents in Civil Engineering, more of them from China

Keywords: patent's description, civil Engineering

Steel roof trusses are the main type of load-bearing structures used in the roofing of industrial buildings. Among them, trusses of the “Molodechno” type have become widespread, in which closed bent-welded profiles of square and rectangular cross sections are used as rods. The use of this type of rolled product makes it possible to create structures without gussets and connecting strips, with a maximum degree of process automation, which significantly reduces labor intensity and reduces the cost of their production. Another feature of the coatings under consideration is their non-running solution. The trusses are located in 4m increments, supported by rafter structures. However, in such a situation, the loads on the truss and the forces in the elements are small, and therefore, and also taking into account the limited range of bent-welded profiles, understressing of the truss elements and excessive consumption of metal are likely. Three variants of coatings with different pitches of trusses were considered, and the metal consumption per square meter of coating was determined. It has been proven that with increasing pitch of trusses, the metal consumption of coatings decreases.

Keywords: "Molodechno", rafter truss, sub-rafter truss, continuous purlin, lattice purlin, truss pitch, metal consumption

The article discusses the possibility of using the ANSYS WORKBENCH software package to calculate the uneven settlement of building foundations. The heterogeneity of the physical and mechanical properties of the soil, the difference in the thickness of the bearing layer and other factors lead to uneven development of settlement. This causes the appearance of cracks in the supporting structures, and in the worst case, the destruction of part of the building or the building as a whole. Methods for calculating settlements are very complex, but using the capabilities of modern computers and computer simulation programs makes it possible to obtain a simple and accurate solution to such problems. To evaluate the deformations of the foundation on heterogeneous soils the ANSYS software package was be used. The proposed method can be used to quantify the uneven settlement of the foundations of real buildings and structures.

Keywords: ANSYS WORKBENCH, foundation, uneven settlement, skew, computer modeling, deformation, finite element method

Studies of a circular cylindrical mesh shell with additional rods and increased rigidity of the supporting ribs were carried out. As part of the search for the optimal design, the criterion of rational material consumption was used. According to the results of the conducted studies, the regularities of the distribution of force factors and deformation parameters were revealed. An assessment of the degree of activity of the work and vulnerability to deformations was carried out. Dangerous areas of surfaces are analyzed, mosaics of forces and displacements are obtained. The contribution of reinforcing elements is determined and the influence of the stiffness of the supporting ribs is revealed. A significant unloading of the spatial structure was achieved and a high level of impact resistance was recorded. A significant decrease in calculated indicators was obtained.

Keywords: cylindrical mesh shell, reinforcement with rods, stiffness of support ribs, optimization, forces, displacements, material consumption

A review of studies of photovoltaic chromatic devices for regulating the transparency of glass and simultaneous generation of electrical energy through an internal photoelectric effect is given. Devices based on thin-film heterostructures with kesterite as a photocell are considered in detail. Kesterite is an absorbing material consisting of copper, tin, zinc, sulfur and selenium, a new promising material for creating "smart" glazing with adjustable transparency. The energy characteristics of coatings based on kesterite are compared with coatings of other types. The prospects of kesterite as a basis for creating effective autonomous photovoltaic windows of adjustable transparency are shown.

Keywords: photoelectric effect, transparency, glass, kesterite, perovskite, silicon, window, energy efficiency, electrochromic effect

The safety of hazardous production facilities is directly related to the reliable operation of pipeline systems, as a failure occurring in the elements of such systems can lead to serious consequences for production facilities and the environment. Since the greatest number of failures is associated with faults caused by corrosion, to increase reliability it is necessary to increase the corrosion resistance of metal of pipeline elements. The article gives an overview of materials for manufacturing parts, the influence of different climatic conditions on the mechanical properties of steels. The developed rotary gate designed for automatic prevention of reverse flow of working medium is also presented. To confirm the serviceability of the design, strength calculation of the structure was carried out, where its stress-strain state under the given loading conditions is considered. As a result, the values of maximum equivalent stresses, maximum deformations and displacements were obtained, which are lower than the maximum permissible ones.

Keywords: pipeline system, pipeline, shut-off valves, swing back gate, mathematical modelling, finite element method

A new building structure is proposed - a welded steel I-beam with a prestressed perforated wall. The prestress in the beam is created by stretching the web and subsequent welding with chords. Before prestressing, holes are cut in the wall. Using the LIRA-SAPR software package, a model is proposed that can be used to study the operation of a prestressed perforated beam (PNPB) structure. The influence of various forms of voids in the wall on the change in the stress-strain state of steel I-beams prestressed by the wall drawing is studied. A preliminary assessment was made of the favorable effect of prestressing in a conventional perforated beam on the stress-strain state of beams with different forms of perforations in the web.

Keywords: steel structures, prestressing, numerical experiment, normal and shear stresses, bearing capacity

The problem of quality in construction and installation works at intermediate stages is being discussed. The role of technical supervision in the construction process is outlined. A proposed indicator, the "Quality Index," is presented for consideration, which reflects not only the quality of the works but also the effectiveness of the technical supervisor's work during the construction process.

Keywords: quality, construction quality, construction quality index, quality coefficient, regulations, technical supervisor engineer

The paper presents the study of the effect of multiple cyclic humidification on the compressive strength across the grain edgewise of laminated veneer lumber (LVL), long-term sustained in conditions with high humidity. A significant decrease in its strength properties during cyclic humidification (up to 18% in three cycles) has been proved. The dynamics of crack growth due to the influence of the humidity factor is given.

Keywords: laminated veneer lumber, timber structures, strength, cyclic dampening, drying cracks, hygrostalness

This article defines the necessary characteristics of the collapse of a group of 10 vertical steel tanks with volumes of 15,000 and 20,000 m3

Keywords: oil industry, petroleum products, accidents, vertical steel tanks, collapse

The article discusses modern approaches to the calculation of embedded parts using the most common computing systems in the design environment. The main purpose of the work is a comparative analysis of the stress-strain state of the support plates and anchor rods when calculating in various computing complexes in order to obtain the most reliable and complete results necessary for the designer to ensure reliability when designing components of building structures. In addition to the above, the article focuses on ensuring the rigidity of the support plates, in case of compliance with which, the nodal structural element is able to withstand a single impulse impact.

Keywords: computing complexes, embedded parts, calculation methods, calculation situations, dynamic coefficient, strength indicators

The paper presents a method for calculating the stress-strain state of composite metal-wood beams, taking into account the compliance of bonds in a nonlinear setting using the SCAD software. In the course of the calculation, the pattern of stress and strain distribution, which is close to the real one, was determined. The concentrations of stresses that are capable of initiating the destruction of the structure are determined. Dangerous areas have been identified that make it possible to predict the mode of destruction of the structure, in order to organize measures to strengthen it. The results of the numerical experiment are confirmed by the materials of physical tests.

Keywords: wooden structure, composite beam, pliable connection, calculation, finite element method, stress-strain state, connection, metal-wood beam

The paper presents a study of the water resistance of joints of load-bearing laminated timber structures using domestic melamine-urea-formaldehyde adhesives (MMFC). The high relative strength of samples dried after soaking and boiling above that established for the increased water resistance group is shown. An assessment of water resistance for three formulations is given, the dynamics of crack growth due to the influence of the moisture factor of MMFC.

Keywords: melamine-urea-formaldehyde adhesives, wooden structures, water resistance of adhesive joints, strength

To create composite building materials with a polymer matrix, various fillers of both plant (wood-polymer composites - WPC) and mineral (mineral-polymer composites - MPC) origin can be used. The article evaluates the feasibility of using twelve different minerals in MPC from the standpoint of strength, cost and weight of the resulting materials in comparison with similar indicators of WPC. By sequentially considering each of the evaluated parameters, the sample of fillers is reduced by excluding combinations with characteristics worse than those of the reference material - a wood-polymer binary composite consisting of wood flour and polypropylene. It has been shown that one of the most effective mineral fillers can be waste from construction industry enterprises, as well as structures recycled during the demolition of buildings and structures.

Keywords: composite, matrix, filler, mineral, wood flour, dust, cost, volumetric weight, strength, elastic modulus, Poisson's ratio

The process of determining the most effective design solution from the point of view of metal consumption for the dome structure of the designed exhibition complex in Rostov-on-Don with a plan diameter of 100 m is considered. Three different dome design options are analyzed. Calculation models were created in the Lira-SAPR software package and calculations of various coating options were performed. The obtained results were compared in terms of rigidity and conclusions were drawn about the possibility and feasibility of using each of the considered design solutions. The most efficient design option in terms of metal consumption was selected.

Keywords: metal structures, dome, metal consumption, material consumption

The provisions on the choice of vehicles for the transportation of prefabricated reinforced concrete structures are considered. Transportation can be carried out using general-purpose and specialized vehicles. The existing rules for loading onto road transport are aimed at eliminating the formation of defects in structures. For loading onto vehicles in structures, various devices for slinging are used - mounting loops, holes, or other elements provided for by working drawings for specific structures. Ensuring the safety of transported structures is possible only when studying the complex system "road - vehicle - transported structures". Factors that should be taken into account when calculating for transport effects: type of product (columns, slabs, panels, etc.) and its design features; type of vehicle (column carrier, panel carrier, etc.) with its characteristics; type of road and speed of transportation.

Keywords: transportation, road transport, loading, precast concrete, slab, truss, column, beam

The article is devoted to the topic of secondary use of oil industry waste, namely drilling mud, as an additive in the production of building bricks. In the article, the most used methods of drilling mud processing in the oil production industry are discussed. To date, there is no ecologically effective method of processing, utilization and neutralization of drilling waste. Processing technologies that involve the use of drilling waste as secondary raw materials are gaining popularity, but are not fully developed. Special attention in the article is devoted to consideration of the use of drilling mud waste as a secondary raw material. The laboratory studies of the application of drilling mud in the production of ceramic bricks are presented, the main purpose of which is to reduce the negative impact on the environment, reduce the costs of transportation, storage, processing of drilling waste, as well as the economy of natural resources.

Keywords: drilling, oil industry waste, drill cuttings, sludge pits, negative impact on the environment, recycling, secondary resource, component composition, construction